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On the Lighter Side => New Theories => Topic started by: Andrew K Fletcher on 23/04/2005 12:07:06

Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/04/2005 12:07:06
Osmosis Capillary action and root pressure are accepted as the driving force for lifting water to the canopy of a giant Californian Redwood, towering a hundred metres and more? And these forces are producing flow rates up to and in excess of a 1000 litres a day in a single tree?

Another theory is that the leaves, which are porous, can somehow suck water from the soil and evaporate it through the pores of the leaves? Ever tried sucking on a straw with a hole in it?


Maybe there is another explanation:

Herald Express, July 6, 1995, page 19.   (local paper in Torbay, Devon)

Eureka!

Cliff experiment pulls plug on 300 year old law of physics

A Revolutionary breakthrough claimed by a Paignton man is to be investigated by top scientists.
Ideas man Andrew K Fletcher claims he has disproved a fundamental law of physics dating back to the 17th century.
And impressed by the historic experiment at Overgang cliff, Brixham, to raise water 78 feet without the support of any artificial aids,
John Hunt, Senior forestry Officer for Devon and Somerset who witnessed the experiment's success last Friday said: 'It was quite impressive.

The rule that water will only rise 32 feet under atmospheric pressure when in a column was effectively disproved."

But Mr Hunt explained that he is a professional forester not a scientist and a report on the experiment would be sent to the Forestry commission 's Alice
Holt Research Station, near Farnham in Surrey, for further investigation.
Mr Fletcher's experiment involves a long water filled plastic tube, strung up the cliffside with both open ends placed in two filled demijohns.
A small amount of a salt solution is added at the top of the tube before it is completely filled with water, this acts as a liquid pulley says
Mr Fletcher, lifting water from one demijohn to the other, thereby disproving Torriceli's 17th century law.
This explains how trees can raise water to their tops beyond the 32 feet limit."
said an ecstatic Mr Fletcher. He believes that the discovery also suggests a mechanism by which all life on earth has evolved from the ground.

The Experiment at Brixham Overgang Cliffs where water flowed vertical up a single 6 mm bore tubing using 10 mils of salt solution, demonstrating that a tiny amount of denser solution can lift effortlessly many thousands of times it’s own volume in water without any artificial aids, demonstrating clearly a non living physical cause of bulk flow in plants trees, animals and humans. The 10 metre limit for lifting water clearly needs some serious revision. View The Historic Event on Youtube as it unfolded all those years ago and ask why has this important discovery been ignored for so long.

Radio Interview with Patrick Timpone on One Radio Network
https://www.youtube.com/watch?v=x68PLE8MXJE (https://www.youtube.com/watch?v=x68PLE8MXJE)
20 years ago Andrew made a phenomenal discovery in circulation and how gravity acts upon fluid density changes that take place in all fluids where water is evaporated. In trees (Where this theory began) evaporation from the leaves alters the density of sap. In the body, the warm lungs and airways provide the same density changes in the blood and other fluids. It was not long before it became obvious that posture was incredibly more important than anyone could imagine. To make use of these density changes and allow them to assist the circulation all we needed to do was to manage our posture.
This was a Eureka moment of such magnitude it went off the scale for Andrew and instantly gave birth to Inclined Bed Therapy.
Show Highlights:
-Andrew explains how learning about how trees uptake water led him to understand the benefits of inclined bed therapy

Video of the Brixham Experiment on Youtube:
Video introduction to density flow on Youtube:
Video of a scaled down version of the Brixham Experiment on youtube:
Video of a simple experiment to show density flow in boiling sugar syrup.

http://andrewkennethfletcher.blogspot.com/


Andrew K Fletcher


Medical Physics Newsletter publications:

http://groups.iop.org/ME/archive_newsletter2002010.htm

http://www.iop.org/activity/groups/subject/med/Newsletter/2003_Archive/page_8262.html

 
Let's start with Osmosis
The work Of Professor H.T.Hammel:
EVERYTHING YOU WERE TAUGHT ABOUT OSMOSIS IS WRONG.


Osmosis is the reason that a fresh water fish placed in the ocean desiccates and dies. Osmosis is the reason that blisters form on fiberglass boat hulls. Osmosis is how waste products of metabolism enter and leave the blood stream. Osmosis determines how you, me and every living thing lives and dies. One would think that a civilization that spends billions of dollars every year on medical research would understand something as basic as osmosis. Wrong, wrong, wrong.
Source: http://www.yarbroughlaw.com/Osmosis.htm
 
Or what about Root Pressure?

Roots can squeeze water to the tops of trees? You what?. ROFLMAO. Sorry but every time I read about root pressure it makes me cringe.

Or maybe capillary action? In other words, a tree is a giant sponge capable of blotting water from below ground level to heights in excess of a hundred metres at flow rates that can exceed a thousand litres of water a day in a single tree.

Does the cohesion tension theory suck? How can leaves create suction when there are pores in them open to the air? Is it not like trying to suck water through a straw with holes in it? And what about when the leaves have fallen in Autumn, where is this magical cohesion generated when there are no leaves?

And then there is the problem with Strasburger's experiments, where he killed all of the living cells in a tree suspended vertically in a bath of picric acid with the roots removed and observed the continued evaporation of the poison several weeks after the death of the tree.


Andrew
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Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 23/04/2005 12:51:55
There is a copy of this in the science trivia section, it might make sense to post comments there, as otherwise the discussion will get fragmented.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/04/2005 17:47:04

l_kryptonite
 
[Another theory is that the leaves, which are porous, can somehow suck water from the soil and evaporate it through the pores of the leaves? Ever tried sucking on a straw with a hole in it?]

I don't get it
Is there a typo here or am I terminally thick?
 
 
Andrew K Fletcher
 
I don't get it either!

 
Andrew K Fletcher

Strange, I thought everyone would be rushing in to defend these pathetic substitutes for common sense
 
l_kryptonite

 Posted - 17 Apr 2005 :  10:16:38    
 
I think you'll find that is supposed to read, "...leaves, which are porous, can somehow suck water from the air and evaporate it..."

This is true. Plants absorb nutrients from a liquid foliar feed faster than from the root system. it is even possilbe to force feed too much by this method.
Imagine, if you will, the effect and absorption rate of a drug which is spread over the entire surface of one's skin, compared to that ingested. the differences would be radical.
 
 
Andrew K Fletcher

 Posted - 17 Apr 2005 :  15:38:34          
 
Nope, the cohesion theory states the long thin threads of water are drawn up to replace the evaporated water,

But there is definately a mechanism for trees to draw water from the atmosphere. I removed a budlia. The trunk had virtually rotted in half and the small shrub like tree fell with very little effort. It remained on my drive throughout the end of last summer and appeared to be dead. The drive is concrete btw. I removed it a few weeks ago to the tip and was amazed to find that it had began growing vertically, despite having no root system and had been thoroughly dehydrated during the summer. I was also amazed at a new species of magnolia, which came from a seed found in a grain storage container, found buried in one of the Egyptian Pyramids.

The bit about absorption though the skin is something I am familiar with and have used to good effect a freshly squeezed lemon, rubbed over my body when I feel a cold coming on, it either vanishes or does not infect me, even though the people around me have it :)

Still does nothing for the conventional theories.

Good point though

 
Andrew K Fletcher

 Posted - 23 Apr 2005 :  11:48:42          
--------------------------------------------------------------------------------
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 24/04/2005 15:20:35
What is the purpose of the massive loss of water in the transpiration process? 98% all water drawn through the roots is evaporated through the leaves and trunk. So what is the purpose of this? And what about the massive loss of moisture from the respiratory system, eyes and the skin, Anyone shed some light on its function?

Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 24/04/2005 20:42:52
There is a really good link that explains a lot about water transpot in plants here:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/X/Xylem.html

Plants do appear to waste a whole lot of water, I guess that is because they have to move a certain amount of minerals up the tree each day.

The xylae must be at a considerable negative pressure, so to move water etc from them into the leaves there must be much more salts and sugars in the leaves to draw the water by osmosis out of a xylem. this means that to get a decent difference you must need a very dilute solution in the xylem. So to move a given amount of nutrients up the tree you need to use lots of water.

I expect there are much more efficient ways of moving nutrients but they would involve changing an awful lot of evolution. Also if water is cheap but energy is expensive, why waste sugar moving the nutrients when you can do it with water and a bit of heat...
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/04/2005 09:29:36
Hi David

I agree that there may be a density change at the leaf, due to the very high evaporation rates from the sap, which contains sugars produced by the leaves and minerals drawn up in dilute form from the soils? In fact, it would be impossible for this massive loss of moisture to not alter the density of the sap at the leaf, would you agree with this statement?

Andrew

Leaves do after all look more like washing hung out to dry than effective solar panels.



Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/04/2005 09:45:24
GCSE Basic Physiology and water transport.

OSMOSIS ?

"I have chosen to relate to the following text book because it is written by a person who like myself is not entirely satisfied by the explanations put forward in the relevant subjects".

 
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi209.photobucket.com%2Falbums%2Fbb31%2FAndrew_K_Fletcher%2FImage13.gif&hash=5d320b82c77a2e862d6689868c726019) Figure C’s results raise the questions; What is osmosis and how are its qualities explained in the text books.

For the currently accepted view of osmosis and all other views on water transport I will refer to one of the standard GCSE text books entitled GCSE BIOLOGY, D.G. Mackean. ISBN 0-7195-4281-2 first published in 1986.

Page 34 fig 3 Diffusion gradient

Page 36 OSMOSIS

Osmosis is the special name used to describe the diffusion of water across a membrane, from a dilute solution to a more concentrated solution. In biology this usually means the diffusion of water into or out of cells Osmosis is just one special kind of because it is only water molecules and their movement we are considering. Figure 3 showed that molecules will diffuse from a region where there are a lot of them to a region where they are fewer in number; that is from a region of highly concentrated molecules to a region of lower concentration. Pure water has the highest possible concentration of water molecules; it is 100% water molecules, all of them free to move.

Figure 9 shows a concentrated sugar solution, separated from a dilute solution by a membrane, which allows water molecules to pass through. The dilute solution, in effect contains more water molecules than the concentrated solution. As a result of this difference in concentration, water molecules will diffuse from the dilute to the concentrated solution. The level of the concentrated solution will rise or, if it is confined to an enclosed space, its pressure will increase. The membrane separating the two solutions is often called selectively permeable or semi-permeable because it appears as if water molecules can pass through it more easily than sugar molecules can.

Osmosis then is the passage of water across a selectively permeable membrane from a dilute solution to a concentrated solution.

This is all you need to know in order to understand the effects of osmosis in living organisms, But a more complete explanation is given below.

ALTERNATIVE EXPLANATION FOR OSMOSIS

The current text book explanation for osmosis appears to have ignored the effects of gravity on liquids. The constant pull of gravity acts differently on concentrated solutions than dilute solutions i.e. The concentrated solution is heavier than the dilute solution and will always settle at the bottom of a reservoir or in this case a vessel.

 
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi209.photobucket.com%2Falbums%2Fbb31%2FAndrew_K_Fletcher%2FImage4.gif&hash=1f55b2e1610350e6fd4294a4fc2ff44c) To see this clearly, picture Fig 9 without the membrane; the result would be that the concentrated solution would sink and the dilute solution would rise. This effect will not stop because of the membrane. The concentrated solution will still cause the dilute solution to rise as we have seen earlier; and as the concentrated solution moves into the opposite side containing the dilute solution, the dilute solution is dragged through the membrane in a circular motion. For every action there must be a reaction. In order to prove this point add a little dye to the sugar solution and watch the exchange between the liquids.

"When the effect that gravity exerts on concentrated solutions is added to the equation of water transport and osmosis, it gives us a very clear understanding of the driving mechanisms involved".

Chapter 7 Transport in plants

page 71

The main force which draws water from the soil and through the plant is caused by a process called transpiration. Water evaporates from the leaves and causes a kind of ‘suction ‘ which pulls water up the stem. The water travels up the vessels in the vascular bundles and this flow of water is called the transpiration stream. The water vapour passes by diffusion through the air spaces in the mesophyll and out of the stomata. It is this loss of water vapour from the leaves which is called transpiration. The cell walls which are losing water in this way replace it by drawing water from the nearest vein. Most of this water travels along the cell walls without actually going inside the cells. Thousands of leaf cells are evaporating water like this and drawing water to replace it from the xylem vessels in the veins. As a result , water is pulled through the xylem vessels and up the stem from the roots. This transpiration pull is strong enough to draw up water 50 metres or more in trees.

Page 72

Most of this water evaporates from the leaves; only a tiny fraction is retained for photosynthesis and to maintain the turgor of the cells. The advantage to the plant of this excessive evaporation is not clear.

A rapid water flow may be needed to obtain sufficient mineral salts, which are in very dilute solution in the soil. Evaporation may also help to cool the leaf when exposed to intense sunlight.

Against the first possibility it has to be pointed out that, in some cases, an increased transpiration rate does not increase the uptake of minerals.

Many biologists regard transpiration as an inevitable consequence of photosynthesis, in order to photosynthesise, a leaf has to take in carbon dioxide from the air. The pathway that lets carbon dioxide in will also let water vapour out whether the plant needs to lose water or not. In all probability, plants have to maintain a careful balance between the optimum intake of carbon dioxide and a damaging loss of water.

Page 73

Humidity if the air is very humid, i.e. contains a great deal of water vapour, it can accept very little more from the plants and so transpiration slows down. In dry air, the diffusion of water vapour from the leaf to the atmosphere will be rapid. ( " I will deal with this point later on because it is very important and has implications for human health ") Air Movements: In still air, the region round a transpiring leaf will become saturated with water vapour so that no more can escape from the leaf. In these conditions, transpiration slows down. In moving air the water vapour will be swept away from the leaf as fast as it diffuses out. This will Speed up the transpiration. Furthermore, when the sun shines on the leaves, they will absorb heat as well as light. This warms them up and increases the rate of evaporation.

Page 73 continued Water movement in the xylem

You may have learned in physics that you cannot draw water up by suction to a height of more than about ten metres. Many trees are taller than this yet they can draw up water effectively. The explanation offered is that, in long vertical columns of water in very thin tubes, the attractive forces between the water molecules are greater than the forces trying to separate them. So in effect the transpiration stream is pulling up thin threads of water which resist the tendency to break.

There are still problems however, it is likely that the water columns in some of the vessels do have air breaks in them and yet the total water flow is not affected. The evidence all points to the non-living xylem vessels as the main route by which water passes from the soil to the leaves.

"This statement suggests that the long thin tubes of the tree ,are used for water transport, which are none-living , therefore must represent the tubes used in my experiments at Brixham."

Page 74

Root Pressure

In Experiment 8 on page 79 it is demonstrated that liquid may be forced up a stem by root pressure from the root system. The usual explanation for this is that the cell sap in the root hairs is more concentrated than the

soil water and so water enters by osmosis (see page 36). The water passes from cell to cell by osmosis and is finally forced into the xylem vessels in the centre of the root and up the stem.

This is rather an elaborate model from very little evidence. For example, a gradient of falling osmotic potentials from the outside to the inside of a root has not been demonstrated. However, there is some supporting evidence for the movement of water as a result of root pressure.

root pressures of 1-2 atmospheres have been recorded, and these would support columns of water 10 or 20 metres high. Some workers claim pressures of up to eight atmospheres (i.e. 80 metres of water)

" A column of water 80 metres high would undoubtedly cause water pressures of eight atmospheres at the roots. However It is very difficult to see how a root could generate 8 atmospheres of pressure."

However, root pressure seems to occur mainly in the young herbaceous (i.e. non-woody) plants or in woody plants early in the growing season and though in many species it must contribute to water movements in the stem. The observed rates of flow are too fast to be explained by root pressure alone.

Transport of salts

The liquid which travels in the xylem is not, in fact pure water. It is a very dilute solution, containing from 0.1to1.0% dissolved solids, mostly amino acids, other organic acids and mineral salts. The organic acids are made in the roots; the mineral salts come from the soil. The faster the flow in the transpiration stream, the more dilute is the xylem sap. Experimental evidence suggests that salts are carried from the soil to the leaves mainly in the xylem vessels.

Transport of food
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The xylem sap is always a very dilute solution, but the Phloem sap may contain up to 25 per cent of dissolved solids, The bulk of which consists of sucrose and amino acids.

There is a good deal of evidence to support the view that sucrose amino acids and may other substances are transported in the phloem. The movement of water and salts in the xylem is always upwards, from the soil to the leaf. But in the phloem the sap may be travelling up or down the stem. The carbohydrates made in the leaf during photosynthesis are converted to sucrose and carried out of the leaf to the stem. From here the sucrose may pass upwards to growing buds and fruits or downwards to the roots and storage organs. All parts of a plant which cannot photosynthesise will need a supply of nutrients bought by the phloem. It is possible for substances to be travelling upwards and downwards at the same time in the phloem.

"note the dual flow has been observed in experiments with concentrated solution and water filled tubes."

 
 

Page 74 continued

There is no doubt that substances travel in the sieve tubes of the phloem But the mechanism by which they are moved is not fully understood.

There are several theories, which attempt to explain how sucrose and other solutes are transported in the phloem but none of them is entirely satisfactory.

Page 75

Uptake of water and salts

The water tension developed in the vessels by a rapidly transpiring plant is thought to be sufficient to draw water through the root from the soil. The precise pathway taken by the water is the subject of some debate, but the path of least resistance seems to be in or between the cell walls rather than through the cells.

When transpiration is slow, e.g. at night time or just before bud burst in a deciduous tree, then osmosis may play a more important part in the uptake of water.

One problem for this explanation is that it has not been possible to demonstrate that there is an osmotic gradient across the root cortex which could produce this flow of water from cell to cell. Nevertheless, root pressure developed probably by osmosis can be shown to force water up the root system and into the stem

page 76

The methods by which roots take up salts from the soil are not fully understood. Some salts may be carried in with the water drawn up by transpiration and pass mainly along the cell walls in the root cortex and into the xylem.

It may be that diffusion from a relatively high concentration in the soil to a lower concentration in the root cells accounts for uptake of some individual salts. But it has been shown (a) that salts can be taken from the soil even when their concentration is below that in the roots and (b) that anything which interferes with respiration impairs the uptake of salts. This suggests that active transport (p.35) plays an important part in the uptake of salts.

The thing that becomes clear from reading the established explanations for water transport is that if it were a bucket, very little water would be transported due to the large number of holes in it !



Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: l_kryptonite on 25/04/2005 11:08:04
Okay, now that I've found the other thread...

I was not disputing the cohesion theory; rather trying to make sense of the sentence in question.
 [the leaves, which are porous, can somehow suck water from the soil]
A leaf cannot possibly suck water from the soil because it is not in contact with the soil.  I assumed incorrectly that you were talking about osmosis.  Although not the main method of fluid movement, it is still an important factor in a plant's survival.


{the leaves, which are porous, can somehow suck water from the soil}
Not all leaves look like this; it is dependant on how much sunlight is needed, and how much danger there is of being scorched.
Plants in areas with competition for light will usually have leaves which lie outstretched and will follow the sun's path to some extent.  An easy example is the rubber plant, a jungle dweller which adapts itself singularly well to stuffy, ill-lit dens all over Scotland.
Take a eucalypt in Africa, however, and notice the immediate difference. Long narrow leaves which seemingly hang limp from the branches actually turn during the course of the day to piont the blade like edge toward the sun in an attempt to restrict water loss and scorching.

It seems that you fellows have given me quite a bit of reading to do.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/04/2005 12:28:02
With regards to the direction that leaves face due to direction of sunlight or energy, could it be that the internal tension on sap is altered or imbalanced due to more tension on one side of a stem than the less exposed side, causing the stem to contort towards the direction of the energy? I.E. Shrinkage on one side of the relatively new stems in new growth supporting leaves.

Andrew

Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 25/04/2005 12:54:32
What exactly does figure 9 show?

I am not really convinced that gravity can have much affect on osmosis as osmosis will move water from an area of low salt (or other things which won't go through the membrane) concentration to one of high salt concentration whether it be up down or sideways.

I don't understand the arguement above, if the salt is above the membrane, gravity can't cause it to move below the membrane as the membrane is by definition impermiable to the salt...
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: l_kryptonite on 25/04/2005 13:04:32
I'm getting way out of my depth here but I don't believe that the same change in tension would cause leaves in one plant to pull one way, and have the reverse effect on another.

Maybe if we knew what makes the leaves of a carnivorous plant move?  Not the trigger, but the motion itself.
The leaves of one mimosa will close at a single touch.  I do know that this is not heat sensitivity because I've tested it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/04/2005 16:08:04
quote:
Originally posted by daveshorts

What exactly does figure 9 show?




FIG 9 represents the standard drawing of osmosis in the GCSE Biol Book referenced above, nothing has changed.



Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/04/2005 16:15:43
Why not? It simpy depends where the tension is applied surely.

quote:
Originally posted by l_kryptonite

I'm getting way out of my depth here but I don't believe that the same change in tension would cause leaves in one plant to pull one way, and have the reverse effect on another.



I have also thought about the carnivorous plants, and have a venus flytrap in front of me now.

could the insects movement stimulate the release of solutes stored at the leaf to be suddenly released and begin to flow rapidly down the stem, altering the internal pressures in front of the falling solutes to become positive and behind the falling solutes to become negative inducing the leaves to be pulled down around the captured insect by said hydraulic forces?

Andrew

Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: l_kryptonite on 26/04/2005 02:09:23
Hm, I believe you may be on to something there.  I'll look into it further.  Maybe interview Dierdrie when she's finished sunning herself this morning.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 26/04/2005 18:29:01
According to:
http://www.news.harvard.edu/gazette/daily/2005/01/26-flytrap.html
and in more detail
http://www.ias.ac.in/jbiosci/bobji2652.pdf

The fly trap leaf is designed so when primed it is a bit like those toy rubber hemispheres which you could turn inside out and were just about stable, but would turn back the right way round quite violently (the toys would jump in the air).

The Flytrap leaf is just about stable open but with a small change in the rigidity of certain parts of the trap near the trigger cells (possibly due to some osmosis related mechanism) it will flip into it's preferred closed configuration, trapping the poor fly.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/04/2005 19:02:44
Thanks Dave, I think Harvard are stating the obvious
You have to admit, it is a bit like saying, when we release the string on a bow, the arrow flies through the air, without adding that we place tension manually on the bow with the addition of a string, then even more tension is added, until the bow string is manually released.

I think what we are trying to establish is how the plant places the charge in its leaves, and the mechanism that causes the leaves to close, which I believe to be a simple hydraulic process, that is easy to demonstrate using very basic and inexpensive lab equipment.

I was hoping that many of the scientists here would rush to defend all the old accepted explanations for fluid transport.


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 26/04/2005 19:51:17
The opening of the trap is less interesting as it happens much more slowly, I would have thought it happened by cells changing shape by gaining or loosing water (possibly by pumping ions in and out of the cells and water following them by osmosis) or by the cells actually growing. I believe it is quite an expensive process energetically for the plant as you can kill it by triggereing it too many times without feeding it.

What do you mean by "all the old accepted explanations for fluid transport." the stuff in the like I posted earlier seemed to be pretty consistent, what is the exact problem?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/04/2005 21:04:20
David

There is no paradigm in the accepted literature that comes remotely close to addressing the bulk flow rates observed in plants and trees.
The new Cohesion theory requires non-cavitation to even begin,let alone addressing the fact that it is impossible for leaves to generate the suction required to pull water from the ground and out through thoe pores, and therefore is a non-starter. Osmosis is utter nonsense when placed against the flow rates, capillary action is laughable and root presure, well, let's not go there :)

quote:
Originally posted by daveshorts



What do you mean by "all the old accepted explanations for fluid transport." the stuff in the like I posted earlier seemed to be pretty consistent, what is the exact problem?



Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 26/04/2005 21:45:50
Why is it impossible for leaves to produce the suction required? If you work out the osmotic pressure produced by just the sugar in orange juice (as an example plant fluid it is easy to get figures for) it comes out at about 9.8 atmospheres, enough to suck water up about 100m (about 300 feet), so as long as the water in the xylem doesn't cavitate it should work fine!

A large tree has tens, or hundreds, of thousands of leaves. So each leaf would only have to suck, by osmosis,   a few militres a day to make up the  1000 litres a day you quoted earlier. Surely this is a perfectly reasonable rate?

I don't think the cavitation problem is as bad as it sounds - for a start we can observe that there are xylem in a tree that are 100m long and they don't cavitate, and in the link I posted earlier it says that branches have been spun in centrifuges so they are experiencing negative pressures equivalent to 92metres of water. So the question isn't "is it reasonable for a xylem not to cavitate?" but why isn't the xylem cavitating?

I would guess the answer to this is related to nucleation. It is possible to heat water above it's boiling point, without it boiling, if you do so in a very clean container. This is because although it is (free) energetically favourable for all the water to boil, to do so it would have to form a bubble. Creating a bubble is difficult because you have to fight against suface tension, and it turns out that to be stable the bubble has to be more than a critical size. Now if the xylem is smaller than this critical size it would be impossible for a bubble to form until the tension is so large that the critical size of the bubble is smaller than the diameter of the xylem.

 I will do some calculations at some point but I guess this will be at considerable negative pressures.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: chris on 26/04/2005 21:49:05
Sorry to elbow in on the discussion. Dave got there with the answer to the flytrap question first (I'm away on holiday this week !), but just so as you know, we did discuss this issue on the radio show in February :

How a flytrap snaps shut (http://www.thenakedscientists.com/HTML/shows/2005.02.06.htm#2)

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 12:41:00
Tubular Water
One way to envision water pulled into and up a capillary tube is to use a suspension bridge model. The column of water is suspended against gravity by its adherence to the walls of the tube. Cohesive force keep all the water molecules together. Capillary movement is greater as tube diameter decreases. Extremely small diameter tubes, pores, or spaces can attract water and move it a relatively long way.
Capillary movement is responsible for within- and between-cell water movement in trees, and small pore space movements in soils. Cell wall spaces are extremely small (interfibral) and can slowly wick-up water. The water conducting tissues of trees (xylem), does not utilize capillary movement for water transport. If xylem were open at its top, a maximum capillary rise of 2-3 feet could be obtained. Xylem transport is by mass movement of water not capillary action.
Capillary movement is a matter of inches, not dragging water to the top of a 300 feet tall tree. Capillary movement components can be seen where liquid water touches the side of a glass. The water does not abruptly stop at the glass interface, but is drawn slightly up the sides of the glass. This raised rim is called a "meniscus." The meniscus is the visible sign of adhesive forces between the glass and water pulled up the side of the glass. The smaller the diameter of the glass, the greater the adhesive forces pulling-up on the water column and the less mass suspended behind.
Tiny Bubbles
Gas bubble formation in water columns is called cavitation. As temperatures rise and tension in the water column increases, more gases will fall out of solution and form small bubbles. These tiny bubbles may gather and coalesce, "snapping" the water column. As temperatures decrease, water can hold more dissolved gasses until it freezes. Freezing allows gases to escape and potentially cavitates water conducting tissue when thawed. Trees do have some limited means to reduce these cavitation faults.
On The Move
Water movement and transportation of materials is essential to tree life. The three major forms of transport are driven by diffusion, mass flow, and osmosis forces.
Diffusion – Diffusion operates over cell distances. Diffusion is the movement of dissolved materials from high concentrations areas to low concentration areas. Diffusion can move a dissolved molecule in water across a cell in a few seconds. Diffusion does not operate biologically over larger distances. It would take decades to diffuse a molecule across a distance of one yard / one meter.
Mass Flow – Most movements we visualize are due to the mass flow of materials caused by pressure differences. Wind, gravity, and transpiration forces initiate and sustain small differences in pressure. These small differences drive water and its dissolved load of materials in many different directions. Because pressure is the driving force in mass flow, (not concentration differences as in diffusion), the size of the conduit is critical to flow rates. If the radius of the conduit is doubled, volume flow increases to the fourth power of the size increase (double conduit radius and flow rate increases by 16 times — 24).
Osmosis – Osmosis is the movement of water across a membrane. Membranes in living tree cells separate and protect different processes and cellular parts. Membranes act as selective filters, preventing materials with large hydration spheres or layers from passing through. Small, uncharged materials may pass freely. The driving force to move materials in osmosis is a combination of pressure and concentration forces called a "water potential gradient."

by Dr. Kim D. Coder
Daniel B. Warnell School of Forest Resources
University of Georgia
6/99


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 14:30:59
Yep that all sounds about right.

As far as I can work out the presently accepted way water gets up a tree is:

The xylem are full of water from the beginning, as each year they grow up from the roots and are full of water from the start.
 This column of water is essentially hanging from the top of the column, and is stable (despite being under considerable negative pressure) because the xylem is so small and covered with hydrophillic substances so cavitation is difficult as I described above (this is known as the cohesiveness of water).

  Now the tissue around the xylem have more sugar and other salts dissolved in them than are in contents of the xylem so they suck water across the cell membranes surrounding the xylem by osmosis. You are right to point out that osmosis is a slow process, but this is happening over the whole area of the tree so it adds up.

Because the water is cohesive if you pull on the top the whole column moves up like a piece of string so it sucks water in at the bottom.

The water in the cells evaporates concentrating the salts and sugars in them, and allowing them to draw more water in by osmosis. So the energy to power the whole process comes from the sun evaporating water in the leaves.

Where is the problem with this picture?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 14:36:18
Dave, lets not forget the limit which suction can work under normal atmospheric pressure in physics. I.E. a pump/suction placed above a water source has a ceiling. Above 10 metres, the pump fails to work, and the water level remains at 10 metres, and the space above the 10 metres is vacuum, the limit was discovered by Galileo, while asked to work out why water at 40 feet below the surface could not be drawn up by a pump. Cavitations do occur and can be heard as cracking noises in a tree using a stethoscope.

Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 15:17:04
As I mentioned earlier it is possible to get water below ther pressure  it should cavitate and therefore be able to suck it up more than 10metres, (in the same way as you can super heat water) especially if you are in a very thin tube covered in hydrophillic substances (or a xylem as it is otherwise known). In fact looking at the web (and from a conversation we had in Brixham once) you have syphoned water 24m vertically using quite a large tube, so it must be possible to do better with this using a smaller tube.

Yes cavitation does happen, especially in drought conditions, but surely that shows that the water in the xylae is under tension and therefore unstable, so is evidence for the standard theory. There are a lot of xylae in a tree and it will be ok as long as the tree is growing the xylae faster than they are breaking due to cavitation.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 16:29:38
Dave, the water at Brixham was not siphoned, as you well know a siphon will not work at those heights. In fact, to prove it was not a siphon that was taking place, I lowered one of the bottles in my experiment to see if siphon would occur, and because there was no saline solution at the centre of the loop of tubing no circulation took place, therefore disproving that we were looking at a siphon.

We can agree now on the fact that cavitations are known to occur. I believe that when a cavity occurs, the pressure changes reverse to a positive downward force, which has a direct influence on fluids in the rest of the tree, forcing the fluids in nearby tubes to rise higher and repair the cavitations, therefore enabling the bulk flow to continue.

Having said that, I am intrigued as to where and when we met, did you attend the demonstration in 1994?

Andrew


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 27/04/2005 17:37:58
Hm, yes... I agree not exactly a siphon in the traditional sense... but i can't see why that matters. Whatever the source of the upward "pull" on the water at the top of the left hand column, it's still just a pull at that point, as would be the pull due to transfer of the water across a cell membrane by osmosis.
I really can't see where this tells us anything new.

BTW I think the guys are talking about this
http://www.the-tree.org.uk/TreeTalk/3Spring2003/Gravity/gravity1.htm
webpage, I googled it but I thought I'd link it to save others the bother (as I couldn't find it higher up the thread).
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 18:32:32
Rosy
Thanks for agreeing with me on the non-siphon effect.
Strange that you cant find anything new in this? The flow rates observed within this simple paradigm parallel any observed rates in trees or plants, if not exceed them with ease. That being because of the obvious fluid friction within a tree or plant and the lesser degree of friction in the tubular models.

One should not jump to the conclusion that current understanding of osmosis is comparative to the efficacy of the new paradigm, without first testing the simple tubular experiments for oneself.
 
Andrew


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 19:09:11
You had at in the experiment a loop of tube filled with water with a height difference from the top to the bottom of more than 10m? So you have prooved that a column of water more than 10m high is stable, so why shouldn't a xylem be able to do the same thing? Especially as it has had 200million years to optmise this process.

You are right what you were doing (injecting denser fluid near the top of the tube on one arm of a syphon loop) is not conventional syphoning, you are making one arm of the syphon heavier by using a higher density fluid rather than by using a lengthened arm, but if this works then a syphon will work.

If the water column has not cavitated there is no reason why it shouldn't syphon - the reason why it is often said that you can't syphon over 34 feet is that the fluid will have a tendancy to cavitate. How far did you lower your bottle, and for how long? If your tube was 150feet long a the system will have a resonant period of about 45 seconds (assuming that there is no damping, which would make this period longer), so to definitely see any effect you would have had to wait at least this long.

What you describe in your 'tubular experiments' sounds entirely reasonable to me and exactly what I would expect to happen from standard physics, but I don't see how it would apply to a tree.

Although you get a downward flow of sugars through the Phloem and an upward flow through the Xylem, as you mentioned earlier, 98% of the water that is lifted up is evapourated, so the less than 2% of water going down would have to lift 20 times that amount of water.
 For the syphon device you describe in the link to work the weight on the downward side must be greater than the upward side or it obviously won't work. Unless the density of the sugar solution is 50 times that of the water coming up I don't see how this could work.


btw. You came to a hands on science event I was running in Brixham a couple of years ago.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 21:15:37
You had at in the experiment a loop of tube filled with water with a height difference from the top to the bottom of more than 10m? So you have prooved that a column of water more than 10m high is stable, so why shouldn't a xylem be able to do the same thing? Especially as it has had 200million years to optmise this process.

*****Answer
A little more than 10 metres actually, 24 metres to be exact, as that was the length of tube I was using at the time.

The column of water is not stable in the tubes, cavitations is demonstrated as the stress on the water bead causes bubbles to form and the columns collapse eventually, just as they do in the tree.
*****



You are right what you were doing (injecting denser fluid near the top of the tube on one arm of a syphon loop) is not conventional syphoning, you are making one arm of the syphon heavier by using a higher density fluid rather than by using a lengthened arm, but if this works then a syphon will work.

*****Answer
Feel free to try your siphon at these heights. Ill bet you draw the same conclusion that many others have already observed as the accepted height at which a siphon will work.

Picture a loop of tubing suspended above the 10 metre limit, producing an unbroken bead of water, under the tension produced by the equal weight of the water on both sides of the tubes. Now initiate the lowering of one of the ground based bottles to try to cause a siphon. The result would be that the lowering of the one bottle would merely cause the bead of water to become elasticised and stretch to the point where it would collapse. But during the stretching process, we hypothetically inject a tiny amount of concentrated saline solution coloured, in one side of the loop at the top/upper most part of the loop. The result would be an obvious independent flow and return system, within the pre tensioned bead of water, flowing with total disregard to pressures, and creating its own pressure changes within the tension placed upon the bead of water.
This flow system does not require pressure in order to function, but delivers pressures as it functions.
*****


If the water column has not cavitated there is no reason why it shouldn't syphon - the reason why it is often said that you can't syphon over 34 feet is that the fluid will have a tendancy to cavitate. How far did you lower your bottle, and for how long? If your tube was 150feet long a the system will have a resonant period of about 45 seconds (assuming that there is no damping, which would make this period longer), so to definitely see any effect you would have had to wait at least this long.

*****Answer
Wrong, there is a fundamental reason why siphon does not occur as explained above.

The bottle was lowered 2 steps, presumably around half a metre, as I did not measure the steps, and remained for well over your 45 seconds without any evidence of siphon.

What you describe in your 'tubular experiments' sounds entirely reasonable to me and exactly what I would expect to happen from standard physics, but I don't see how it would apply to a tree.
*****Answer
According to the points you raise above, this is not quite correct, as your understanding of the siphon does not apply here.
*****

Although you get a downward flow of sugars through the Phloem and an upward flow through the Xylem, as you mentioned earlier, 98% of the water that is lifted up is evapourated, so the less than 2% of water going down would have to lift 20 times that amount of water.

*****Answer
This paradigm can lift many thousands of times the volume going up, and only requires a minute of solutes flowing down to cause the greater volume of less dense solution to flow up, giving the tree more than enough water to evaporate and produce a denser sap.
*****
For the syphon device you describe in the link to work the weight on the downward side must be greater than the upward side or it obviously won't work. Unless the density of the sugar solution is 50 times that of the water coming up I don't see how this could work.
*****Answer
This is where you go wrong David: imagine a 24 mil bore tube on one side and a 6 mil bore tube on the other side, blended seamlessly together to form a single looped open ended tube of different sizes immersed at equal levels in two bottles of water, suspended 24 metres vertically by the centre. The weight of the 24 mil bore side of the loop will be counterbalanced exactly by the 6 mil bore side of the tube, with no net movement either way. Now add the tiny amount of salt to the 6 mil bore side at the centre and circulation begins. In the case of the tree, the structure and size differences of the tubes compensates for the loss of moisture through the leaves and returns the resulting concentrates back towards the ground.


btw. You came to a hands on science event I was running in Brixham a couple of years ago.


I do remember popping in the town hall now you mention it, as you were closing your event I believe.

Thank you for remembering me.

Andrew
 


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 22:56:47
quote:
imagine a 24 mil bore tube on one side and a 6 mil bore tube on the other side, blended seamlessly together to form a single looped open ended tube of different sizes immersed at equal levels in two bottles of water, suspended 24 metres vertically by the centre. The weight of the 24 mil bore side of the loop will be counterbalanced exactly by the 6 mil bore side of the tube, with no net movement either way. Now add the tiny amount of salt to the 6 mil bore side at the centre and circulation begins.


This system will produce a flow, but because the amount of water in the system is allways the same, if you get 1 litre falling out of the 6mil tube, the 24mil tube will suck up 1 litre, however because the area of the bigger tube is 16 times larger the water you have sucked up will only go up 1/16th of the tube, you haven't pumped any water to the top.

quote:
In the case of the tree, the structure and size differences of the tubes compensates for the loss of moisture through the leaves and returns the resulting concentrates back towards the ground.


But how are you getting the water out at the top? The water is at a negative pressure, this means that to get it out you have to pull, and pull very hard against a large pressure. Evaporation will do this, but if evapouration is doing the  work you don't need the tube coming down and that is just the conventional model you are so dead set against.


In what way has your system produced a net flow of  water to the top of the cliff? Overall you have moved water from one jar to another one next to it. If you had filled a bowl of water at the top of the cliff that would be equivalent to what the tree is doing, and I will belive it could be an issue when you can do that.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 23:00:14
quote:
Picture a loop of tubing suspended above the 10 metre limit, producing an unbroken bead of water, under the tension produced by the equal weight of the water on both sides of the tubes. Now initiate the lowering of one of the ground based bottles to try to cause a siphon. The result would be that the lowering of the one bottle would merely cause the bead of water to become elasticised and stretch to the point where it would collapse. But during the stretching process, we hypothetically inject a tiny amount of concentrated saline solution coloured, in one side of the loop at the top/upper most part of the loop. The result would be an obvious independent flow and return system, within the pre tensioned bead of water, flowing with total disregard to pressures, and creating its own pressure changes within the tension placed upon the bead of water.

So would it break if you lift one of the jars, which will reduce the tension in the water column...?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/04/2005 23:35:45
Yes David, cavitation will inevitably cause the columns to collapse. The additional tension placed upon the bead by lowering the level of one side, merely serves to hasten the process of cavitation. Even if you raise a jar following initial lowering, the cavitation is already underway. In the link that Rosy put on her post, I have tried to address the way cavitations continually form and self repair within the multi conduit system of a tree. Cavitations do not interfere/interrupt the flow within the narrow tubes of the bench top model. In fact, the cavitations/bubbles behave oddly when sufficient saline solution is added. They are observed to flow down instead of up, and there is water flowing around the bubbles also.

Fascinating to see bubbles flowing down instead of up. Maybe you might want to test the simple bench top version for yourself?




Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/04/2005 23:47:51
But there is no difference in the pressure of the water at the top of the tube, between your clifftop experiment  and an equivalent syphon, so I don't see why you think one will work and the other won't. What sized tube did you use for your experiments?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 08:43:11
Yes! Altering the heights of the 2 jars merely serves to place additional stress on the fluids within the unbroken bead of water. Therefore, the collumn is not permanently stable, as is so in the tree and plant. The tree gets around this problem by having an outer sleeve (bark) and a multi conduit system inside the outer sleeve. This enables the resulting pressure change when cavitation occurs, to gain height due to the resulting downward force on the broken bead, pushing up fluid under greater force to refil the broken bead.


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 08:56:22
quote:
Originally posted by daveshorts

quote:
quote]

This system will produce a flow, but because the amount of water in the system is allways the same, if you get 1 litre falling out of the 6mil tube, the 24mil tube will suck up 1 litre, however because the area of the bigger tube is 16 times larger the water you have sucked up will only go up 1/16th of the tube, you haven't pumped any water to the top.


The model is simple, I do not have the time nor the inclination to try to construct a perfect artificial tree.

I only have to show the driving force in this paper. The trees design takes care of evaporation as the water and minerals flow though its veins

quote:
In the case of the tree, the structure and size differences of the tubes compensates for the loss of moisture through the leaves and returns the resulting concentrates back towards the ground.


But how are you getting the water out at the top? The water is at a negative pressure, this means that to get it out you have to pull, and pull very hard against a large pressure. Evaporation will do this, but if evapouration is doing the  work you don't need the tube coming down and that is just the conventional model you are so dead set against.

Common sense should tell anyone that there is no attempt to extract water from the tubular models


In what way has your system produced a net flow of  water to the top of the cliff? Overall you have moved water from one jar to another one next to it. If you had filled a bowl of water at the top of the cliff that would be equivalent to what the tree is doing, and I will belive it could be an issue when you can do that.



I have never seen a bowl of water at the top of any tree other than those left by the owners of apple trees to prevent scrumpers.

In the case of a tree, we could place a plastic bag over a branch and collect and extract the condensed water in its canopy.

It is possible to design a model that can lift sea water, extract pure water and return the denser ballast to the sea through a tube in order to provide the pumping for the desalination. But I have long since given up jumping though loops to amuse people.





Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 09:05:10
Quote
but if evaporation is doing the work you don't need the tube coming down and that is just the conventional model you are so dead set against. [quote/]

Evaporation is doing the work. But not in the way it has been erroneously interpreted by Dave et al. I am perplexed that you have stated that there is no downward flow in trees?

From an earlier post in case you missed it:
Transport of salts

The liquid which travels in the xylem is not, in fact pure water. It is a very dilute solution, containing from 0.1to1.0% dissolved solids, mostly amino acids, other organic acids and mineral salts. The organic acids are made in the roots; the mineral salts come from the soil. The faster the flow in the transpiration stream, the more dilute is the xylem sap. Experimental evidence suggests that salts are carried from the soil to the leaves mainly in the xylem vessels.

The xylem sap is always a very dilute solution, but the Phloem sap may contain up to 25 per cent of dissolved solids, The bulk of which consists of sucrose and amino acids.

There is a good deal of evidence to support the view that sucrose amino acids and may other substances are transported in the phloem. The movement of water and salts in the xylem is always upwards, from the soil to the leaf. But in the phloem the sap may be travelling up or down the stem. The carbohydrates made in the leaf during photosynthesis are converted to sucrose and carried out of the leaf to the stem. From here the sucrose may pass upwards to growing buds and fruits or downwards to the roots and storage organs. All parts of a plant which cannot photosynthesise will need a supply of nutrients bought by the phloem. It is possible for substances to be travelling upwards and downwards at the same time in the phloem.


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 28/04/2005 10:24:59
Hm, I'm not at all convinced.
Transport of sugars between living cells (such as in the phloem) actually requires the input of energy. Sugars use ATP (the cellular energy transfer compund) to move sugar (and amin acid, and any charged or bulky species) molecules across cell membranes, including across the boundaries between seive plates.
I simply can't see how this is compatible with the idea that the gravitational potential of the more concentrated solution is lifting the water up the xylem.

quote:
It is possible to design a model that can lift sea water, extract pure water and return the denser ballast to the sea through a tube in order to provide the pumping for the desalination. But I have long since given up jumping though loops to amuse people.
 


I can't imagine how... no need to design a system, but would you like to outline the general principles...?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 12:55:43
Rosy, please repeat the simple experiments and understand the driving forces of nature.

If you cant get hold of the tubes, joints and syringe body, let me post them to you.

1. It is an impossibility of the highest degree for evaporation to take place from a liquid containing solutes of salt and sugars, without concentrating said solutes.

2. It is a function of gravity to act upon said solutes when they occur at an elevated point above less concentrated solutes. (see Atlantic conveyor system)

3. For every action there is a reaction. Any downward flow will cause an inevitable upward flow!

4. The experiments have been demonstrated at Primary level education, in schools. At secondary schools, at Universities, at Derriford Hospital’s Physics Department in Plymouth. At the London International Inventions Fair in 1997, witnessed by some 3 thousand visitors and inventors. On Westcountry Television News, BBC Radio in Paignton, and has not yet failed to convince all who have witnessed its efficacy in delivering the flow rates observed in plants and trees!

Now why can’t you understand the simplicity of this discovery and its many applications?

Nevertheless, I am grateful for all of the replies on this thread and thank you for your input

Andrew


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 28/04/2005 13:35:26
I know how the experiment works. That's not my question.
It's quite obvious from your description how the weight of the solution pulls the (lighter) water over the top of the tubing.
But at the top of the loop, as in a conventional siphon, the water is at much less than atmospheric pressure (it has to be as there's a force holding up the column of water below) so I don't see how you propose that the water gets out of the xylae into the leaves (essentially the question Dave put further up the thread).

You haven't explained to me how your proposed system for lifting sea-water works.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 13:40:16
The following review came from a letter I wrote to professor H T Hammel,
who is member of the Max Plank Institute.



Within a 2 weeks I received his reply

INDIANA UNIVERSITY

SCHOOL OF MEDIICINE date September 6/ 1995

Dear Mr Fletcher:

I received the information you sent me regarding your ideas about fluid
transport in trees, in tubing and in the vascular system in humans.

I will study your ideas and comment upon them as soon as possible. A Quick
scan of your Brixham experiment prompts me to ask if you conducted this
experiment with boiled water without any solute added to the tubing on
either side of the central point which you raise 24 meters? I expect that
you could raise the tubing to the same height with or without solute in the
water. In any case , your experiment confirms that clean water (water that
is unbroken water, water that is without a single minute bubble of vapour)
can support tension of several hundreds of atmospheres. The record tension
obtained experimentally is 270 atmospheres. At 10 degrees C. (c.f. Briggs,
L. Limiting negative pressure of water. Journal of Applied Physics 21:
721-722 1950).

I expect even this tension at brake point can be exceeded by careful
cleansing of the water, to remove even the most minute region of gas phase.
When the water is already broken, as occurs when gas is entrapped on
particulate matter in ordinary water, the water will expand around even a
single break when tension (negative Pressure) is applied to the water. When
you boil the water, prior to applying (2.4-1) ATM negative pressure to the
water in the highest point of the tubing, you eliminate some of these breaks
in ordinary water. I expect that dissolving NaCl or other solutes in the
water will have little or no effect on the way you measure the tensile
strength of water.

I am enclosing some reprints that may interest you. Some of these deal with
negative pressures we have measured in tall trees, mangroves and desert
shrubs. Other reprints deal with how solutes alter water in aqueous
solutions and how colloidal solutes (proteins) affect the flux of protein
free fluid between plasma in capillaries and interstitial fluid.

Sincerely H.T. Hammel Ph.D.


Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 13:42:16
From: Hemetis
To: AndrewKenneth Fletcher
Sent: Saturday, March 04, 2000 2:51 AM
Subject: RE: NEW THEORY FOR FLUID TRANSPORT Re: How does water really reach
the tops of trees?08/August/1999


Hi Andrew :-)

You have the honor of being a true scientist and experimentalist.
Yet you have to answer for some big questions.
1- You have to explain the results of "Strasburger 1893" who killed the
lower part of an Oak with picric acid and demonstrated that "all" the stem
raised a "Fuchsin aquatic solution".

****
I am not familiar with the above mentioned experiment and would appreciate
more details.

Acid rain causes the death of many trees. Has anyone considered the fact
that an increase in acid will cause an increase in the rate at which
minerals are dissolved. For instance, if I pour battery  acid on concrete,
it dissolves!

If you increase the amount of minerals in water, you increase the specific
gravity of said water. When you relate this to the Brixham Exp. Any increase
in the S.G. of the water contained in the upward flowing side of the tube
will reduce the flow in the downside!

If the water at the said container becomes too heavy, the experiment would
stop or at least slow down to the point of almost stopping. The tree would
face the same problems according to the gravity theory. However, if the
weather conditions promoted accelerated evaporation from the leaves, this
would compensate for the heavier water at the root and transport would
continue.

Killing the bottom part of the tree would not cause the circulation to stop,
it would not even prevent the tree from drawing water from the soil.
The xylem is after all already dead and the downward flow would simply find
another route, possibly into a xylem, or by oozing from a damaged part of
the tree.




2- There is an established "Cohesion theory" which explains most of your
theory and you have to show what is the difference.

****
I am unaware of anyone showing water flowing vertically up to 78 feet.

Correct me if I am wrong, but cohesion simply explains how water bonds to
water. I fail to see how this could explain bulk flow vertically up or down.

As for chemical reactions at the leaf causing electrical influences on water
and then effectively transporting a hundred gallons of water from the roots
of a mature oak to the leaves, just does not work for me. If it has been
shown experimentally, I will swim the ocean and shake your hand tomorrow.

Once you have observed water flowing in tubes, and I sincerely hope you will
try at least the benchtop model, you cannot deny the existence of gravity
driven circulation! The efficiency of this system sets it aside from all
other attempts to explain fluid transport.

Since 1994, I have convinced many scientists, including Professor Edzard
Ernst at Exeter together with three doctors, Professor Michel Cabanac,
University Laval, Quebec. Professor H.T.Hammel. Emeritus member of the Max
Planck Instiute, Dr David Cutler, Kew Gardens, Forestry Commission
Scientists- who also attended the Brixham Exp. Professor Chui Exeter
University. and many many more. Yet nothing happens. I also know the reasons
why nothing happens!

3- If "salt solution" must "fall under gravitation to pull a water column up
and that is how the plant "feeds", how can you explain water circulation in
horizontal plants being so ordered as xylem feeding forward and phloem
feeding backward?

Horizontal flow? If I lay a water filled tube horizontally, with salt
solution added at the middle of the tube and the ends capped off, there
would be water transport spreading outwards from both sides of the saline
solution, and in order for this to happen, clean water would be drawn
towards the centre of the salt solution.

Even horizontal plants are elevated to some degree above ground level and
roots are usually below the surface of the soil. this is all that is
required to trigger transport.

4- How do you explain the homogeneity of climbing plants when they make a
down turn following the light- intensity?

The energy source in the soft part of plants would alter the pressures in
the xylem and phloem on one side of the stem, causing the plant to turn
towards the energy source.

Imagine a length of string attached to the trunk and running through soft
new growth in a tree. Give the string a pull and the branch is bent towards
which ever side the string is inserted.


5- In some ground plants the stem grows horizontally on the ground and we
can see multiple root systems along the stem and multiple shoot systems as
well, How do you explain the sap streams in such a plant, where all roots
absorb water and all shoots transpire. What is the direction of the flow?
where does your theory fit?
Do you think it is bidirectional? Or do you have to admit that the dead duct
network provides the path to the living parts, where one would push and
another would pull "on demand" and on cell to cell interactions.

The new shoots and roots would set up an independent flow system, which uses
the main flow systems water to operate. Take a cutting and it grows
independently to the plant it is cut from.

The roots on such a plant face down and the leaves point up.


So, yes your experiment is a wonderful verification for the Cohesion theory
which explains the minimum requirement of energy for water transport in a
living plant, where mineral and sugar diffusion from production line to
assembly of polymers locations would pull the associated water along with it
and must be replaced "Cohesively".

6- In many houses we have hanging pots for plant decoration in which plants
"hang down from the pot.
Do you have the slightest doubt that water in xylem is moving down and water
in phloem is moving up?
This should disprove your theory completely.

You can't disprove the truth! You can cloud its validity with words, but
clouds have a nasty habit of letting the light through at times.

Oh boy, do I have some doubts.

If  I shaped my tube loop to the exact shape of the plant you refer to and
released the saline solution at the same point as the leaves would release
their sap, you would still see gravity driven circulation, from a single
cell to a giant redwood, it makes no difference to gravity. Try it!
Furthermore, if there is a U bend in the plant, roots will form at the
bottom of the loop and this is used effectively to take cuttings from some
plants by pegging a branch so that it is covered in soil.


So think deeply because your contribution to science is valid experimentally
but your theory is defective.
That is why I have been repeatedly encouraging you to study plant physiology
deeply and check the established theories profoundly before you postulate a
new one.

We are studying plant physiology deeply as we exchange views and I am very
grateful for the opportunity to share your knowledge.

I do have a fair bit of knowledge in this field. However my work has led me
to helping people with neurological conditions, but that should be left out
of this discussion.

Regardless of your theorization I must congratulate you for the wonderful
experiment that should be known by your name.
In the history of science thousands of scientists have contributed to the
bulk of experimental data.
Yet few make it to the top including Clowns like Einstein.

With best regards.

EL Hemetis

Thank you for these words, they show me that some people at least are not
shackled to the powers that be.
Your integrity is admirable.

Kind regards

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 28/04/2005 16:12:54
I don't see how the two quotes you have made strengthen your case, the first one just says that cohesion theory means that the experiment that you have carried out is possible, the second one is an extract from this thread:
http://www.the-tree.org.uk/MessageBoard/thread.php?id=53&pos=0 which is remarkably similar to this thread, and E.L. Hemetis brings up most of the same critisisms as I have.
quote:
I have never seen a bowl of water at the top of any tree other than those left by the owners of apple trees to prevent scrumpers.

Of course there isn't!!! This is because the whole process is driven by evaporation concentrating salts and sugars in tthe leaf, which causes osmosis to suck water out of the top of the xylem, and then the cohesion of water means that the whole column is pulled up, so it sucks more water in at the bottom.
 So the water leaving the top is as a gas, so it won't fill up a bowl.

Just to make it clear, it is not water cohesion that is doing the pulling, but osmosis, cohesion just means that the water behaves like a wire, so if you pull the top water gets sucked in at the bottom.
quote:
In the case of a tree, we could place a plastic bag over a branch and collect and extract the condensed water in its canopy.

Exactly, because evaporation is providing the energy to lift water against gravity, so the water coming out of the tree is a vapour.
quote:
It is possible to design a model that can lift sea water, extract pure water and return the denser ballast to the sea through a tube in order to provide the pumping for the desalination. But I have long since given up jumping though loops to amuse people.

It isn't to amuse people, it is to address what is the fundamental challenge to your hypothesis. The experiment in Brixham didn't lift more water than it dropped down. A tree lifts 50 times more water up the xylem than comes down the phloem.

 It takes one joule of energy to lift 1 a kg of 1 metre. A litre of water weighs 1kg a litre of sap may weigh 1.5kg (a generous estimate). The litre of sap falling 10m will release 15J of energy, this is enough to lift 1.5l of water back up the 10m. However a tree lifts 50l of water etc. up a tree this means that you need to get 48.5J of energy from somewhere. In the conventional model this energy comes in the form of heat evaporating water at the top of the tree. Where is it coming from in your model.

If your model can do this with no other energy inputs there would be a lot more interest in it than just from plant biologists as you would have built a perpetual motion machine.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 16:32:36
One only needs to show the method of circulation. Evaporation is an inevitable consequence of water flowing through the massive surface area of a tree.

Evaporation with a plastic bag over a branch? maybe water oozing from the leaves is a more likely explanation. Evaporation requires a dry air, suns energy and wind. High humidity shuts down transpiration (common knowledge) The environment inside the plastic bag would be near 100% humidity. So where does your accepted without question theory address this :) Mine fits with it like a glove.

Maybe you would like to explain how evaporation from the trees leaves can alter the concentration of solutes at an elevated point, and gravity does not affect the flow of these concentrated solutes. I wait with bated breath



Death is natures way of telling us to slow down.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 28/04/2005 17:08:19
quote:
One only needs to show the method of circulation. Evaporation is an inevitable consequence of water flowing through the massive surface area of a tree.


If evaporation is driving the process, you do not need a downward tube to lift water up the tree! If evaporation is not putting in the energy you need to get energy from somewhere for your hypothesis to work.

There are phloem in a tree, but they are not needed in order to lift water up.

quote:
Evaporation with a plastic bag over a branch? maybe water oozing from the leaves is a more likely explanation. Evaporation requires a dry air, suns energy and wind. High humidity shuts down transpiration (common knowledge) The environment inside the plastic bag would be near 100% humidity. So where does your accepted without question theory address this :) Mine fits with it like a glove.


The definition of 100% humidity is that water will condense at the same rate as it is evaporating. So for some evaporation you either need a humidity of less than 100% or the leaf to be at a higher temperature than the air (if you boil a pan of water it will still evaporate, even if you are in a room at 100% humidity), which it will be on a sunny day. So what is happening in your bag is the water is evaporating from the leaves which are hot as they are a dark colour and condensing on the plastic bag which is cooled by the external air.

If the water was oozing out of the leaves and not evaporating this would bring up the problem with energies I mentioned earlier.

quote:
Maybe you would like to explain how evaporation from the trees leaves can alter the concentration of solutes at an elevated point, and gravity does not affect the flow of these concentrated solutes. I wait with bated breath


The solutes are in cells and therefore behind cell membranes which are impermiable to the solutes. As Rosy mentioned earlier a cell has to use energy to pump large molecules through a cell mambrane.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 28/04/2005 17:09:41
So, guys, do we know what *does* happen when you tie a plastic bag to a tree?? I'd expect it to reach a certain humidity level (higher than atmospheric) within the bag and then even out.

You would possibly then find that the leaves started to release xylem sap, by pumping ions across the cell membrane (and energy-expensive process) and allowing water to follow them. Also via a transport protein but not (this time) one which requires energy to function (I'm a bit hazy here, and my cell biology notes are 60 miles away, but that's the gist).

From http://plantphys.info/Plant_Physiology/transpiralec.html
quote:

Root pressure is also sometimes visible on leaves. Under conditions of high humidity, cool temperature, and low light exposure root pressure can push xylem fluids through leaf mesophyll and out some larger pores in the leaves called hydathodes. Thus on a cool morning as you walk across the grass you notice a drop of liquid on the tip of each blade. You may have thought this was dew, but because it is on the upward pointing tip, you realize that this cannot be so. A test of solutes would demonstrate that this is xylem sap, not condensed humidity! The process by which this exudes is called guttation and it is driven by root pressure.


I don't know how much plant physiology/cell biology you've studied, so forgive me if I'm teaching my grandmother to suck eggs... Plant cell membranes are impermeable to sugars such as sucrose. Transfer of sugars from cell to cell, as in the phloem, occurs only when the cell "chooses" to expend energy on the process. Thus, except where sugars *are* being moved about by active transport, there essentially isn't a "flow of concentrated solutes" to deal with, any more than there's a "flow of cells".
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 22:18:29
Dave, ever thought about becoming a politician?

Please read
standard GCSE text books entitled GCSE BIOLOGY, D.G. Mackean. ISBN 0-7195-4281-2 first published in 1986.

Posted earlier

To state that solutes and sugars stay put and are not acted upon by gravity is absurd! How do we tap rubber, harvest amber and maple syrup?????? There is an obvious downward flow!!!! And for every action there must be a reaction !!!!!


Please repeat the simple experiments, or give me an address and i will personally come to you and set them up so that you can see what exactly we are talking about here.

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/04/2005 22:21:25
Rosy, my point is that accepted explanations for bulk flow are erroneous, and do not account for this amazingly simple, yet hitherto overlooked paradigm

Andrew

Suck it and see
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 28/04/2005 23:53:01
quote:

To state that solutes and sugars stay put and are not acted upon by gravity is absurd! How do we tap rubber, harvest amber and maple syrup?????? There is an obvious downward flow!!!! And for every action there must be a reaction !!!!!



Maple syrup is quoted on various websites as being an anomally in that it is harvested from the xylem and has a concentration of sugar as high as 2%. This is given as a remarkably high concentration not normally found in the xylae.
Presumably to make the syrup we're familiar with as a pancake dressing they have to boil it up a bit ;)
We don't harvest amber, it's a fossilised form of tree resin.
Sap and rubber are secreted by trees in response to injury.
Rubber is not part of the tree's transport system at all.
From http://www.worldwildlife.org/bsp/bcn/learning/primer/impacts.htm
quote:

It is useful in this context to briefly examine the physiology of rubber production by Hevea trees. Rubber latex is manufactured in special cells using stored carbohydrates. In addition to rubber, the latex contains proteins, sugars, tannins, alkaloids, and mineral salts. Although the exact biological function of this rich concoction is unknown, biochemically it is very expensive for the tree to produce. The abundant production of rubber latex by Hevea trees is an abnormal response to injury--a tapped tree produces hundreds of times more latex than it would have formed had it not been tapped. The net result is that commercial tapping regimes cause the tree to divert a considerable proportion of the resources normally used for growth and reproduction to the production of rubber.


Resin (the sticky stuff that you see on the outside of, say, pine trees when they're injured) is a defence mechanism rather than something involved in bulk flow.

Everything acted on by gravity must by definition go downwards?
Really? Even if it's on top of something else? I don't usually find myself going through the floor into the basement. The sugars are on top of an (impermeable, to them) cell membrane, so there's no reason why they shouldn't stay put.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/04/2005 10:03:21
Rosy
http://instruct1.cit.cornell.edu/courses/biog105/pages/demos/105/unit5/cuttreephotos.html
Your statement about maple syrup merely serves to highlight that the flow and pathway of sugars can be reverted under certain environmental conditions, namely late winter, in which it is currently thought that the cold nights cause co2 gas bubbles to form due to the hydrolysis of starch, which expands during the warmer daytime altering the pressure in the xylem from negative to positive.
This is precisely why sugars and minerals are found to be more abundant in the roots of deciduous trees during the fall.
I have also mentioned this in my paper, as pressure changes are observed in the xylem when cavitation occurs, or when the leaves cease to function of fall in autumn. Fits perfectly with the new paradigm.
Amber by the way is Harvested in Poland and the Ukraine to make ornaments and jewellery, it is also heated up to form shapes in moulds, while retaining the trapped insects, although this often fragments the insects, whereas naturally formed amber maintains the insects perfectly.
Under normal transpiring conditions, the sugar pathway and flow is in the phloem. But as you state, it is harvested when the water transport is suppressed by winter.

Yes even if its on top of something else! Take a look at the flow of dense rock pulled towards the Earths core. Keep eating the doughnuts and you might find yourself on the basement floor.


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 29/04/2005 13:38:40
My apologies, the structure of this post may be a little confused as I had to go to a class part way through writing it and haven't time to start from scratch and make it into comprehensible prose(!!)
I think I've made all the points I intended to, however!


If the primary system for moving water up trees is this convection type system you're proposing, how do the sugars get *up* the trees to the ends of the branches for leaf formation in the spring? According to your model, if there aren't any leaves yet how does the flow get started and worse how does it draw more sugars (and amino acids and whatever else it needs) up than it drops down (which it must in order to construct new leaves)? It's got to use active transport in the phloem.

OK, my understanding of the current model (and I'm in no sense a plant scientist).
In the leaf cells, sugar is produced and water is lost by evaporation from the leaves.
Sugars are transferred by (mainly passive) transport (depending on the concentrations) into the phloem. Given the sugars are already (since they're made in the leaves and moved to other parts of the plant) moving down a concentration gradient, there is no reason for more water to follow them across the cell.
Loss of water from the leaves results in water being drawn up from the roots via the xylae(osmosis).
The sugars want to move to a position of lower energy/higher entropy (and so to places where there is less sugar already). There *is* an energy gain in going downwards, yes, but as Dave points out it isn't actually very big if you're losing a whole load of water at the top. Your Brixham experiment depends on using the weight of the water coming over the top of the loop to draw the water below it up. In order to produce any energy at all the salt/sugar solution has actually to move downwards, which in your model it can't do unless the water which it pulls up follows it straight back down the opposite tube. Indeed, as was pointed out by EL Hemetis, there is before us the evidence of plants quite happily growing with their leaves below their roots. I'm far more convinced by the idea that that concentration effects dominate.

Where is the need for a "simpler" explanation? The current model doesn't strike me as any more complicated than yours (and you have yourself shown that provided there's a sufficient upwards "pull" water can sustain the "tension" required), given that the mechanisms I've outlines are undoubtedly present in generalised cells and therefore presumably in trees.

Amber really is just the fossilized stuff. The "amber" people harvest is probably copal, which I *think* is a form of resin.
http://www.emporia.edu/earthsci/amber/copal.htm

Also, the falling through the floor thing... if I eat too many doughnuts I may fall through the floor. But only by breaking the floor. The only way of applying the same argument to sugar solution is to say that the sieve plates between phloem cells rupture. Which is OK unless the tree's ever going to want to move nutrient solutions "uphill", which is going to require (energy expensive) active transport because as you so rightly say, all other things being equal heavy solutions (and indeed rocks) want to move downwards with gravity *if the thing they're resting on can move out of the way to allow this*.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/04/2005 16:36:54
quote:
Yes even if its on top of something else! Take a look at the flow of dense rock pulled towards the Earths core

But that is because the thing the rock is sitting on is acting as a fluid (over the timescales involved anyway). From my experiments it doesn't matter how long I stand on the floor (from observation of wardrobes up to a period of a couple of hundred years) I am not going to fall through the floor.

quote:
To state that solutes and sugars stay put and are not acted upon by gravity is absurd! How do we tap rubber, harvest amber and maple syrup?????? There is an obvious downward flow!!!!

Surely you say later that maple syrup is liquid flowing upwards (through the xylae) powered by Carbon di-oxide.
quote:
And for every action there must be a reaction !!!!!

Indeed this is a fundamental part of physics, however this relates to forces not flows. Eg if I push the wall it pushes back, if the rocket pushes hot gas downwards the rocket gets pushed up, if the earth's gravity pulls something down then the earth gets pulled up slightly.

 It doesn't necessarily relate to fluid motion in a tree - this is obviously the case as there is 50 times more fluid going up than down

here is an interesting link:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Phloem.html

The Phloem are at a positive pressure, even near the top of the plant - if they weren't aphids would have to suck the sap out, as it is even if just their mouthparts are left in the stem sap will come out. According to your theory the Phloem must be at a negative pressure (to pull the water up the xylem) so if there is a positive pressure there must be something else going on.


quote:
"The explanation requiring the fewest assumptions is most likely to be correct."

There is a slight caveat to this, the explanation has to explain the observed phenomena - microscopically as well as on the large scale.

If I were a tree designer and I could come up with a way of absorbing carbon dioxide without loosing water I would try and design my tree using something like your principle, especially if I were designing my tree to work in arid conditions as you would avoid having to lift huge amounts of water just to get a few minerals. However if you look at a tree microscopically it isn't cosistent with the structures you find there.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/04/2005 17:38:51
quote:
Originally posted by rosy


If the primary system for moving water up trees is this convection type system you're proposing, how do the sugars get *up* the trees to the ends of the branches for leaf formation in the spring? According to your model, if there aren't any leaves yet how does the flow get started and worse how does it draw more sugars (and amino acids and whatever else it needs) up than it drops down (which it must in order to construct new leaves)? It's got to use active transport in the phloem.


Firstly, it is not a convection system. It is a flow and return system which operates when concentrations of denser solutes occur above less dense solutes due to evaporation.

In the spring, there is an initial temperature change, which initiates the flow and return system, causing the circulation inside the leafless tree to flow, and to generate both positive and negative pressures within the moving fluids as it goes.

 
quote:
sugar is produced and water is lost by evaporation from the leaves.
Sugars are transferred by (mainly passive) transport (depending on the concentrations) into the phloem. Given the sugars are already (since they're made in the leaves and moved to other parts of the plant) moving down a concentration gradient, there is no reason for more water to follow them across the cell.


Actually there is a very good reason for more water to follow, that being the cohesiveness of water molecules adhering to water molecules. This is precisely why I keep asking you to repeat the experiments.

 
quote:
Loss of water from the leaves results in water being drawn up from the roots via the xylae(osmosis).


Absolute nonsense, osmosis requires the belief that water can attract water up a tree and out through the leaves? I cannot see any logic in your argument here.
quote:

The sugars want to move to a position of lower energy/higher entropy (and so to places where there is less sugar already). There *is* an energy gain in going downwards, yes, but as Dave points out it isn't actually very big if you're losing a whole load of water at the top. Your Brixham experiment depends on using the weight of the water coming over the top of the loop to draw the water below it up. In order to produce any energy at all the salt/sugar solution has actually to move


Sorry, I disagree with you, the weight of the water in the opposing side is irrelevant, however, the density of the fluid in the opposing side can counterbalance the flow, much the same as overfeeding a plant can cause it to whither and die, or the same as acid rain can alter the density of the soil water by dissolving minerals too effectively.

This flow has nothing to do with the weight of the water in the opposing side of the loop. Let me try to clarify what is now known in relation to your argument. Picture a loop of tubing causing a slow but steady siphon effect. Now picture a small amount of saline solution injected into the top of the rising side of the siphon. Result: The coloured solution will flow in the opposite side to the siphon, and can be clearly seen in the turbulence of the coloured solution as it interacts with the clean solution. But the saline solution will not flow down without dragging on the water causing a two directional flow. I have seen this and you too can see it if you conduct the experiments for yourself!


 
quote:
, which in your model it can't do unless the water which it pulls up follows it straight back down the opposite tube. Indeed, as was pointed out by EL Hemetis, there is before us the evidence of plants quite happily growing with their leaves below their roots. I'm far more convinced by the idea that that concentration effects dominate.



This flow system will always run in the path of least resistance, be it horizontal, down or up, it makes no difference. But somewhere within the plant or tree, there is a pathway for gravity to draw solutes down, be it in the branches, the trunk, or the roots.
Picture a u shaped branch on ivy, eventually roots will begin to form at the bottom of the u branch. In fact some of the tallest trees on earth have u shaped branches.

quote:

Amber really is just the fossilized stuff. The "amber" people harvest is probably copal, which I *think* is a form of resin.
http://www.emporia.edu/earthsci/amber/copal.htm[/quote]

Ok I will concede that it may not be true amber in the sense of fossilized resin, but the stuff did come from a tree all said and done [:I]
Andrew


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/04/2005 18:21:42
quote:
Absolute nonsense, osmosis requires the belief that water can attract water up a tree and out through the leaves? I cannot see any logic in your argument here.

You may find this stuff interesting about osmosis
http://www.chaosscience.org.uk/pub/public_html//article.php?story=20050301222247333
and
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/ospcal.html
has a nice program for calculating osmotic pressures

If evaporation keeps the concentration of the liquids in teh leaf hight, osmosis can generate the appropriate pressures to suck water out of the xylem, and the column of water in the xylem behaves like a wire (because it is cohesive) so if you pull at the top the whole column moves up, it all sounds consitent to me...
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 29/04/2005 18:56:06
Yeah, I saw that.
Could you have a look at this (mainly for tone) before I post it?

quote:
Firstly, it is not a convection system. It is a flow and return system which operates when concentrations of denser solutes occur above less dense solutes due to evaporation.

Yes, OK...  I know it's not really convection, but it's still a "water goes up, gets heavier, comes down" system. I was being lazy.
quote:
In the spring, there is an initial temperature change, which initiates the flow and return system, causing the circulation inside the leafless tree to flow, and to generate both positive and negative pressures within the moving fluids as it goes.

How???
quote:
Actually there is a very good reason for more water to follow, that being the cohesiveness of water molecules adhering to water molecules. This is precisely why I keep asking you to repeat the experiments.

I don't *think* this applies in the phloem. The water has to cross cell barriers, which it has to do by moving through pores which as I understand it would tend to disrupt the intermolecular forces holding water molecules together. The rules applying to tubes have to be looked at very carefully before we can apply them to the phloem cells which (as I keep saying) are split up by cell membranes. I don't have time to look up the (1st year undergrad cell biology textbook) information on this. I'm assuming you've looked at some texts at a higher level than GCSE, because although my biology mostly isn't up to much I do know that the GCSE chemistry syllabus is so much oversimplified as to be largely meaningless (I only ask because you quote so extensively from a GCSE text further up the thread).
quote:
Absolute nonsense, osmosis requires the belief that water can attract water up a tree and out through the leaves? I cannot see any logic in your argument here.

WHAT??????????
Of course water has to cohere in the xylae for osmaosis to work. The osmosis occurs at the cell membranes of the leaf cells there has to be a column of water sustained in the xylae the height of the tree. That relies on cohesion.
quote:
Sorry, I disagree with you, the weight of the water in the opposing side is irrelevant

Um, the weight of the solution is relevant. I know you don't accept it but what you've got there is fundamentally a syphon. Look up how syphons work and do the maths.
quote:
The coloured solution will flow in the opposite side to the siphon, and can be clearly seen in the turbulence of the coloured solution as it interacts with the clean solution.

You're introducing a coloured solution with a sideways velocity into a stream of water with a pre-existing velocity upwards. Sure you're going to see turbulance.
And, until the solution has largely diffused out into the rest of the water the water with the salt/dye in it will tend to go downwards, being denser than the water around it. That's all completely standard.
However, I would expect, if you add a significant quantity of salt solution that the rate of flow of water over the top of the loop to decrease measurable (you'd have to add the solution part way up the "up" tube rather than at the top or some of the solutes would be drawn over to the "down" tube and mess up the experiment before the system stabilised.
quote:
But somewhere within the plant or tree, there is a pathway for gravity to draw solutes down

Sure about that? I'm absolutely convinced I've seen plants in hanging baskets etc in which most of the leaves are below the basket and consequently below the roots.
quote:
This flow system will always run in the path of least resistance, be it horizontal, down or up, it makes no difference. But somewhere within the plant or tree, there is a pathway for gravity to draw solutes down,

So, like a syphon, then ;)
Only applies if the roots are, overall, above the leaves. As they aren't in hanging baskets.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/04/2005 21:57:01
No not like a siphon at all, but I guess you will never know and have no inclination in exploring the experiments for yourself. What you have there is a fundamental flaw in your analogy of this beautifully simple flow and return system. There is an excellent attempt at explaining a siphon on the link below.
http://www.straightdope.com/columns/010105.html

Within my system, the two ends of a single tube can be pre-filled with water, and a small amount of saline solution added at one end of the tube, which is then joined together. Lift / elevate the saline contaminated end of the loop and the flow system works perfectly. If soft wall tube is used, the saline flows rapidly down causing that side to dilate and the opposing upward travelling side to be sucked in, indicating a negative and positive pressure caused by the action of gravity on the saline solution.
NOT, as in the siphon, pressures causing the flow. This is the flow causing the pressures and that is a monumental difference between the two methods.

RE Hanging baskets: Roots above the leaves. And leaves above leaves, it makes no difference where the roots are. Absolutely no difference to this system whatsoever, because as the stem bends over the basket, the loop still enjoys exactly the same forces from gravity.

“Tree Logic was created by Natalie Jeremijenko. It is made with 6
Flame Maple trees which have been hanging in MASS MoCA's Courtyard B.
Tree Logic at MASS MoCA was sponsored by the Sterling and Francine Clark Art Institute will, over time, vividly demonstrate the obvious fact that plants grow toward the sun. Showing that trees are dynamic natural systems, and Tree Logic reveals this dynamism.”
http://www.fordfound.org/publications/ff_report/images/03_sp_films1.jpg
The trees have been at Mass MoCA long enough that the branches have begun to turn and travel upward. The idea that Jeremijenko uses here in this exhibit is the idea of showing simple and obvious facts of life in biology in an extreme way.
Walker Metcalfe


I am surprised that you think that a mere cell wall, or pit, or an osmotic membrane for that matter could tear water apart. The bonding between water molecules is phenomenal, withstanding very high tensile stress. This force can easily pull water through the obstacles you mention.


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/04/2005 22:12:30
Thoroughly enjoyed the animations, which do not represent the movement of osmosis, having been exaggerated to stress a point, nevertheless, we are dealing with a non-living force, in very simple apparatus, so in the morning, I will set up a hundred metre example of this model, and we should see water flowing effortlessly out at the top of it.

But this would not fit with the xylem, as there is no concentration gradient in the xylem, where the water flows up. However, there is a concentration gradient in the phloem where the water flows predominantly down, sometimes horizontal and occasionally up (for Rosy’s benefit) J

Tell you what Dave, conduct the U experiment shown in the theory with salt solution one side and clean water the other, no membrane. Leave it stand for a week if you like suspended by both open ends and report back how much water has flowed out the top of either side of the tube.



quote:
Originally posted by daveshorts

quote:
Absolute nonsense, osmosis requires the belief that water can attract water up a tree and out through the leaves? I cannot see any logic in your argument here.

You may find this stuff interesting about osmosis
http://www.chaosscience.org.uk/pub/public_html//article.php?story=20050301222247333
and
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/ospcal.html
has a nice program for calculating osmotic pressures

If evaporation keeps the concentration of the liquids in teh leaf hight, osmosis can generate the appropriate pressures to suck water out of the xylem, and the column of water in the xylem behaves like a wire (because it is cohesive) so if you pull at the top the whole column moves up, it all sounds consitent to me...



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/04/2005 22:51:01
Both a syphon and what you are describing work because one arm is heavier than the other

Both are analagous to a piece of rope over a single pulley - if one side has more weight on one rope it will move down. In your system the extra weight is caused by the extra density of the salt, in a conventional syphon this is produced by an extra length of water.

If water had no cohesion it will only work if the water is kept in compression by atmospheric pressure so neither system would work above 10m as the pressure would become negative. However with a very small clean tube you can produce a negative pressure at the top without it cavitating, due to the cohesion of water.

The cell membranes will not rip the water molecules apart, but they will stop the solutes form moving, and if the salt in your system can't move then your circulation will not happen.

What did you think about the links on osmosis?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/04/2005 23:08:20
Sorry I started writing that last post before you did.

There doesn't have to be a concentration gradient within the xylem, you just have to have a concentration gradient between the xylem and the cells in the leaf.

What would be more analagous would be having a 10+m pipe with the top end covered with a partially permiable membrane and strong salt solution on the other side . It will be horribly slow as the suface area of the end of the tube is very small.
eg
Code: [Select]

     _____   <-  membrane
     |   |
     |   |
     |   |
     |   |   <- code
     |   |
  |__|   |__|
  |  |   |  | <-resivoir
  |_________|


It may actually be easier to see an effect if you just put dry salt on the membrane as then it will be more sovious if it is getting wet.

out of interest where are you getting the partially permiable membrane from in the morning?

Also if you want to produce a very large pressure difference you will have to support the membrane very well as over an appreciable area the pressure will build up to a large force and rip the membrane.

I will see if I can find some tube and try it out on a small scale to test the feasibility of it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/04/2005 23:09:57
in the diagram where i wrote code I meant tube... I think I need to eat supper ;)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 30/04/2005 09:10:43
Dave, Sorry, I was being sarcastic about trying it in the morning and you do not deserve it, and I appreciate your replies to my posts.

I really do know that it won't work, any more than a barometer will raise water above the 33-34 feet limit, water cannot be drawn that high by suction, using the most carefully maintained pump, let alone a semi-permeable membrane and some salt. We would both be on a hiding to nothing. It has long been known that there is a limit to the height that water can be drawn up using a capped ended tube. Get to 33 feet and the water simply tears away from the capped end of the water filled tube as it is raised above the reservoir, shown in your drawing. I have observed this many times. In fact, when the bead of water cavitates in the Brixham experiment, the water in both sides falls to the 33 feet limit, leaving vacuum above the limit and water below it.

If it were that simple, I would never have bothered to come up with a new theory.
The problem is that the membrane is also permeable to air, and the water will not rest in the tube. However, capillary action will work to a short distance using very fine tubes, however, to get it to raise to any appreciable heights, the capillary tubes used are often finer than those found in the xylem.

To my knowledge there is no working model other than mine that can demonstrate water circulating as effectively without a pump, not even a tree comes close. This is obviously due to a trees internal structure and the friction caused by it. Which incidentally must generate some heat, and is probably why many trees do not freeze in freezing temperatures.

Using dry salt on the membrane as you suggest may get wet, even if it is not in contact with the water, due to its ability to pull water from the air when it is in its dry state. Mangroves, leaves often show salts crystallized on them, but this is evidence of the evaporation and resultant salt build-ups.



quote:
Originally posted by daveshorts

in the diagram where i wrote code I meant tube... I think I need to eat supper ;)



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 30/04/2005 14:27:22
You see I think your experiment prooves that it is possible.

Why isn't the water cavitating at the top of the tube in your experiment? It is the pressure that drives cavitation, if it is below the vapour pressure of water the water will prefer to be a gas than a liquid, so it ought to be boiling.

If you consider the case of your experiment and a sealed tube (made out of the same substance as your tubes were) the pressure at the top will be identical, so they should behave similarly. If the water is over 10m high the pressure will be negative and it should be cavitating in both cases.
Code: [Select]
    _________                __
    /   ___   \              |  |
    |  /   \  |              |  |
    |  |   |  |              |  |
    |  |   |  |              |  |
    |  |   |  |              |  |
    |__|   |__|              |__|
    |  |   |  |              |  |
Now your experiment has very cleverly shown that water will not allways cavitate (this is something I didn't know before talking to you and is very interesting) as although on balance it would prefer to be a gas, breaking the surface tension is difficult so the probablility of cavitation is low enough for you to do your experiment without it allways cavitating. If the surfaces of the tube are covered with something hydrophillic (water loving) and made very small, the probability of cavitation will be lower.

Now I think this means that the single tube should be similarly stable.

I think you are right putting dry salt on the top of the column would probably mean that air can get to the membrane and you would get cavitation (This may be why trees tend to cavitate more in droughts as the membranes at the top dry aout allowing air in at the top -> a cavitation), but if we slightly alter the design to be more like a real tree and have the top of the membrane covered with a strong solution it may well work eg:
Code: [Select]
       |__________|
        |__________|  <- concentrated solution
            |  |
            |  |
            |  |
            |  |
          ..........
            |  |
            |  |
         |__|  |__|
         |  |  |  |  <- water
         |________|

As now the concentrated solution at the top will act as a seal over the membrane stopping gasses getting in.

I think I will try a small scale version of this at home using some of the thin stuff you get between onion layers as the membrane- I think making the membrane strong enough to support 10m of water will be difficult but that is a purely engineering problem.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 30/04/2005 16:55:00
Andrew
I don't understand in what way the link to the "straightdope" site supports your argument. Cecil Adams describes it what happens beautiffuly, and then rejects the idea based on the fact that the water will cavitate above 10m.
As your experiment establishes that it will *not* necessarily cavitate that problem with the syphon vanishes.
The reason why a barometer can only go up to 10m, driven by atmospheric pressure, is because the water, whilst it will cohere to itself, cannot stick to the top of the barometer tube so a vacuum forms against which 1 Atm supports a 10m column.
In a loop of water, if there is no cavitation then there can be a syphon. If cavitation occurs, as you say, the water on both sides falls back to form two 10m columns.
The syphon works because the pressure at the top of loop is due to the weight of the water in the columns of either side. Since this weight is greater in the longer column there is a net force over the top of the loop towards the longer column.
Your system, likewise, has a greater weight of water/solution in the "down" column.
The pressure change in the soft tube on injection of an amount of concentrated solutiondoesn't seem to me to be particularly surprising. The soft tube absorbs the energy of the change in height of the extra weight and then transfers it back to the water by evening out the flow.
I don't think this is particularly relevant... the weight is still providing the energy, there's just then a delay in transferring it back into the system.

And the water in two different cells, when separated by a cell membrane, isn't in contact in the first place to it isn't "torn apart" by the cell membrane.
In order for the water to pass between cells it has to pass through a *very* small pore... too small for a glucose molecule to pass through. This has got to involve breaking some water-water hydrogen bonds!!
This process is due to two factors, osmotic potential and pressure. There'll be an effect due to the weight involved here (a pressure factor), but the osmotic effect works the other way as that's how the concentration gradient runs.
I don't know how much water actually gets out of the bottom of the phloem. Anyone (Andrew? Dave?) want to find some figures? Is it actually known?

Maple trees growing upside down... well, they don't seem to have died of all their solutes falling to the leaves. And of course the branches turn upwrds again as they grow, that's where the sun is!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 30/04/2005 19:02:29
Rosy, the concentrated sap in the phloem that is not actually taken up by the trees increasing growth cycle, is rediluted by incoming water from the soil, under a negative pressure generated by the falling sap.

Rosy
Be my guest and try to make a siphon work over the 10 metre limit. It does not work!, the weight of the water in the lowered side of the inverted U tube, merely stretches the water until it breaks and a cavity forms, causing the water to fall to remain at the 10 metre mark. As the Brixham experiment demonstrates, it is possible to raise the water in excess of 14 metres, but eventually the water bead will break. When I say a siphon will not work, it is because I have actually tested it!

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 30/04/2005 19:26:50
quote:
Rosy, the concentrated sap in the phloem that is not actually taken up by the trees increasing growth cycle, is rediluted by incoming water from the soil, under a negative pressure generated by the falling sap.

OK, I have absolutely no idea what this is supposed to mean.
How on earth can the falling sap generate negative pressure in the roots? I think I must have misunderstood what you mean by this.
quote:
As the Brixham experiment demonstrates, it is possible to raise the water in excess of 14 metres, but eventually the water bead will break. When I say a siphon will not work, it is because I have actually tested it!

I'm afraid I simply don't believe that this is because it's impossible.
If you can (1) have a column of water 14m high, which you've shown you can and (2) you can exert a downward force on one side of the loop by introducing the extra weight of a few ml of salt solution.
I'm very interested to know how you conducted your syphon experiment (whether you set it up with two containers at different levels then raised the syphon tube, or whether you established the raised loop then raised/lowered one of the containers... I'm interested as which you did will influence rises/drops in pressure (I wonder because you refer to the "lowered side" of the inverted U.
Of course, I'm aware that you're in the very difficult position of attempting to prove a negative, and so you can win only by reasoned argument... and I'm not making your life easier by not being convinced ;)

Sadly I'm not currently in a position to carry out the experiment to my own satisfaction at present (or any time between now and mid-June) as I'm in Cambridgeshire (no cliffs) and don't have the kind of access to a high level window/the ground below it I'd need to do anything contructive.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 01/05/2005 17:14:59
Rosy
Ive thought of a way to explain what happens when you try to siphon higher than 33 feet limit.

Picture some play slime /goo stuff that kiddies (and me) play with, when you pinch a little between your finger and thumb and try to lift the rest of the mass, it stretches until it snapps off. This happens with water inside the tube also.

With regards to the falling sap generating a negative pressure at the roots, relates to the suction at the lower part of the tree that draws water in. Even if the roots are removed, the suction is still there, rulling out root pressure as a driving force. What I should have said to be more accurate is; the falling sap generates a positive pressure in the phloem in front of the falling sap, and a negative pressure is caused behind the falling sap.

Hope this helps

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 01/05/2005 17:51:24
Just to clear up a quick point that may have been causing confusion:
When me and Rosy are talking about negative pressure, we mean negative absolute pressure - where a vacuum is zero pressure.

The reason why GCSE textbooks tell you that a syphon will not work above 33 feet is that atmospheric pressure is enough to lift water 33feet, so up to this point the water is under compression by the atmospheric pressure. If you go above 33feet the water is in tension (a negative pressure) and should therefore boil or cavitate or something breaking the syphon.

Now as you have found out real life is rarely as simple as GCSE textbooks, and water can actually survive a negative pressure if it is continuous, there are minimal dissolved gasses (which you removed by boiling) because of the cohesiveness of the water. It is not stable like this and a small bubble will cause it to cavitate. However if there are no gasses this is unlikely enough for you to do your experiment in Brixham.

Now if you are using the same liquid in both tubes the pressure in the tube is only dependent on how much weight there is pulling on it, and the chance of cavitation is just dependent on the pressure. So the only difference between a normal syphon and your syphon is that the extra weight is provided by an extra length of water rather than salt.

Would your syphon work if you added the salt near the bottom of the system? if so how is this different from adding an extra weight of water by lengthening the tube?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 01/05/2005 22:00:03
Originally posted by daveshorts[/i]
 
quote:
When me and Rosy are talking about negative pressure, we mean negative absolute pressure - where a vacuum is zero pressure.


Is there any other kind of negative pressure?

 
quote:
The reason why GCSE textbooks tell you that a syphon will not work above 33 feet is that atmospheric pressure is enough to lift water 33feet, so up to this point the water is under compression by the atmospheric pressure. If you go above 33feet the water is in tension (a negative pressure) and should therefore boil or cavitate or something breaking the syphon.


Not sure that I’ve read anything about siphons not working at 33 feet in a gcse biol book? I’ve read it on plenty of other places on the web though. You do appear to be saying the GCSE Biol book is wrong, and that I something we can agree on at least.

Pascal demonstrated that the siphon worked by atmospheric pressure, not by horror vacui, by means of the apparatus shown.  The two
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.du.edu%2F%7Ejcalvert%2Ftech%2Ffluids%2Fhstat4.gif&hash=518d0b897d57b11aaabcef02874c461d)beakers of mercury are connected by a three-way tube as shown, with the upper branch open to the atmosphere. As the large container is filled with water, pressure on the free surfaces of the mercury in the beakers pushes mercury into the tubes. When the state shown is reached, the beakers are connected by a mercury column, and the siphon starts, emptying the upper beaker and filling the lower. The mercury has been open to the atmosphere all this time, so if there were any horror vacui, it could have flowed in at will to soothe itself.
source: http://www.du.edu/~jcalvert/tech/fluids/hydstat.htm#Siph

 
quote:
Now as you have found out real life is rarely as simple as GCSE textbooks, and water can actually survive a negative pressure if it is continuous, there are minimal dissolved gasses (which you removed by boiling) because of the cohesiveness of the water. It is not stable like this and a small bubble will cause it to cavitate. However if there are no gasses this is unlikely enough for you to do your experiment in Brixham.


Agreed

 
quote:
Now if you are using the same liquid in both tubes the pressure in the tube is only dependent on how much weight there is pulling on it, and the chance of cavitation is just dependent on the pressure. So the only difference between a normal syphon and your syphon is that the extra weight is provided by an extra length of water rather than salt.


Dave, I believe there is something else at work in this model, I believe the molecules of the dissolved salts align in conjunction with gravity as they mix with a greater volume of clean water in the same side. I.E. the more dilute the saline becomes and the greater the distance it spreads out, the greater the flow rates achieved, say thrice times the normal rate of decent and accent accordingly, depending on the height. It appears that the higher the experiment goes the greater the flow. Still trying to figure out how to set a scale of flow so that everyone will agree on the formula :)

On occasions, the saline flow has triggered a very rapid flow, as opposed to the normal stable flow. It can’t be a siphon effect that it is triggering because there is no additional weight or density to the downward flow.   When a small amount of saline solution is added in a way that it can flow in both directions over the inverted u centre, you can clearly see the flow at work and the turbulence it causes in the ascending side as well as the descending side. The best place to view this is on a spiral staircase. I’ve often used the one in the local car park for my experiments.

Siphoning is used on a large scale to move huge volumes of water for irrigation from one reservoir to another. However, they find that this does not work if the height is too great and have to install a pump to maintain a positive pressure.

Even the smaller bench top model of the Brixham experiment reveals some amazing properties.

For example: cavitation can be observed, even at the low level. The syringe body filled with saline remains stable while the tube is in the elevated position. After injecting a small amount of coloured saline solution in at the top, the syringe begins to self-empty as the plunger is pulled up against gravity by the descending saline solution. This is pretty amazing when you consider that say 1 mil of saline solution is injected and 5 mils of saline solution are drawn up as the plunger rises from a near vertical down position and joined to a small length of the same tube to the T junction.

I have seen a siphon work on many many occasions. This simply is not a siphon at work here.

Yes the saline solution can be injected into any point on the descending side and the flow will occur. But as I stated earlier, the higher up you add it, the greater the flow rate.

What would you expect to happen to the water levels in the tube, when you remove the both ends of the tube from the bottles, while it remains suspended above the 33 feet limit?  


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 02/05/2005 02:47:42
I am not quite sure what you mean by "the molecules of the dissolved salts align in conjunction with gravity". Gravity is my molecular standards an increadibly weak force the energy released by rotating all the water molecules to align with water would release less than a nano joule of energy - in comparison heating it up by a degree centigrade would require over 4kJ a difference of a trillion times. So on this scale thermal and intermolecular forces will hugely dominate any gravitational effects.

Gravity only becomes important at larger scales, so we can model water as a fluid affected by gravity rather than worrying about what happens on the molecular scale.

I think you would expect the syringe to be pulled in if you plug it into something with a pressure below that of a vacuum. It may stick in the beginning though. which is why it wasn't moving to start with. Have you tried a similar experiment injecting pure water into the system, and found out what happens to the syringe?

Yes the cohesiveness of water is an effect that is stronger the smaller the tube you use, and the cleaner the water, so syphoning huge amounts of dirty irrigation water is unlikely to work at over 10m.

Just a thought, have you taken into account the momentum the water in the tube will have once it starts moving. (This will not be insignificant if my experiments using a hosepipe to move a level around my parents barn are anything to go by)

Once the water starts moving through the tube it will tend to keep moving. I think this is why you get more flow when you put the saline in at the top, than when you put it in the bottom. When you put the saline in the top it will accelerate under gravity pulling the rest of the water with it. The further it drops the faster the saline, and the whole water column will be going. When it gets to the bottom, now the column is moving it will want to keep on moving because it has inertia, so it will keep syphoning(ish) until it slows down due to friction.

quote:
What would you expect to happen to the water levels in the tube, when you remove the both ends of the tube from the bottles, while it remains suspended above the 33 feet limit?

I would guess that the water would start to fall out of the bottom of the tubes as what is known as a slug bubble goes up them (basically what happens if you cover the top end of a tube and lift it out of the water - air goes up the middle and water comes down the sides.

Now through random factors like the exact sizes of the tubes and which one you took out of the bottles first one tube will empty a bit quicker than the other. This will mean that there is more weight on the side of the slower tube, which should start a syphon going which will pull the fast emptying side up faster and faster as the pressure difference between the two sides gets bigger. This would mean that you get more water out of one side than the other, and the difference between the rate of flow out of the tubes should get larger with time.

I am not sure how strong the syphon effect will be relative to them just emptying as I think this is dependent on the diameter of the tube. This is assuming that the fiddling with it doesn't trigger a cavitation.

How close am I? I am really interested to see how good my physical intuition is.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/05/2005 09:21:06
Well, I did have a rather long conversation with a huge group of people on a physics newsgroup about whether gravity is actually a weak force or a strong force, and I did get quite a few people on to my way of thinking eventually, showing that you simply cannot take one pre-defined unit of gravity and measure it against 1 pre-defined unit of say EMF, as the comparison should have been measured against the total pull of the mass of the whole planet, because isolating any part of the mass does indeed result in the measurement of only one tiny part of the mass. Therefore collectively, the mass will always logically be greater than the sum of the smaller part of the mass.

But that’s another argument for another day.


I think you would expect the syringe to be pulled in if you plug it into something with a pressure below that of a vacuum. It may stick in the beginning though. which is why it wasn't moving to start with. Have you tried a similar experiment injecting pure water into the system, and found out what happens to the syringe?

Good, at least we now agree on the negative pressure issue. Actually, I have tried it at the same height of elevation without the solute, and the syringe body remains unaffected, as does the flow. However, as you correctly state, if we go substantially higher with the inverted U tube, the syringe will become sucked in by the negative pressure/tension placed upon the water.

Now using a complete loop of water filled soft walled tube (used to demonstrate how this flow could affect fluids in the body) once the saline solution starts to flow down one side, the turbulence becomes obvious as some of the coloured solution is pulled up one side and down the other side, proving complete rotation / circulation of the loop is taking place.

An obvious and very significant narrowing of the upward flowing tube takes place, and an equally obvious and significant bulging of the opposing downward flowing side of the tube takes place. Indicating the presence of both a negative and positive pressure, generated by the falling salt solution.

I have obviously thought about the momentum of the water. But you have just highlighted something very significant for me, which I believe has just explained my observations on the sudden acceleration of the water in the tubes during flow. Thanks Dave, you’re a star!

What I’ve just gleaned from our conversation is: The water is very elastic and stretches substantially when placed under tension, as does the analogy of using the play slime, mentioned earlier to Rosy.

The sudden acceleration is due to the sudden release of the built up elastic tension, caused by the falling salt solution on the opposing clean water-side of the loop. Just like releasing a stretched elastic band. This fits exactly with my observations when removing the two ends of the water filled tubes out of the two bottles and the water level rises up the tube by half a metre! Proving the amazing elasticity of water. The water remains suspended, even if we blow up one side of the tube, it temporarily alters the level in the side you are blowing up, but the water stays in the tube suspended almost like two weights linked by an elastic band and hung over a wall. More like two weights on an equal length of wire, joined by an elastic band in the middle and hung over a wall. Picture lifting one of the weights gently releasing the tension on the elastic band, but not sufficient as to over balance the weight in the other side. Amazing!
If there is some salt left inside one side of the inverted loop when both ends of the tubes are removed together, the saline side begins to draw up the water in the adjoining side, accelerating as it goes, until all the water flows out of the one side only!  6 mil bore tubing, hard nylon, which resists the negative tension more than adequately.


 But you were pretty close Dave. Do you live close to me in Paignton? Perhaps we could meet up and to give you a demonstration of the exp?


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/05/2005 12:51:35
l_kryptonite
I disagree; your contribution is as valuable as anyone else’s. New-ground in science renders everyone on equal terms. Children being in the best position of all to take on board a new paradigm, as they have not been corrupted by erroneous literature and retain the capacity of having an open mind.

I agree with your statement that: A leaf cannot possibly suck water from the soil because it is not in contact with the soil. I assumed incorrectly that you were talking about osmosis. Although not the main method of fluid movement, it is still an important factor in a plant's survival.



quote:
Originally posted by l_kryptonite

Or you could get involved in the incredibly complex discussion being held in the general science section.  I need to do about 3 years of study before I get back into that one though. Way out of my league.




"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 02/05/2005 13:56:51
Thre are two things that could be causeing the effect you are referring to as the elasticity of the water. The stretching of the water or the deforming of the tube.

If we start on the stretching of the water. I have found a list of how the volume of water changes as you change the pressure.

temp F(C) 0 atm 500 a 1000 a 2000 a 3000 a
32 (0) 1.0000 0.9769 0.9566 0.9223 0.8954
68 (20) 1.0016 0.9804 0.9619 0.9312 0.9065
122 (50) 1.0128 0.9915 0.9732 0.9428 0.9193

so at 68 farenheit it takes 500 atmospheres to change thevolume by 2%, so 1 atmosphere will change the volume by about 2%/500 = .004% or about .4mm over 10m

Ok tension will be slightly different but probably not hugely so and most of the water in the column is at a positive pressure anyway so I don't think that the expansion of water will be producing a major part of the effect.

Your tube is pretty rigid, but if you squeeze it really hard I expect it will deform a little bit, you would only need a 5-10 percent deformation to cause a .5m movement in the water. Are you using the flexible clear PVC tube or the translucent white much more ridgid stuff?

Hang on a minute - do I understand you correctly in that the bottom half metre of the tube empties and is full of air, and then stops? Have you done anything else other than removed the demijohn? because just removing the demijohn will not alter the pressures at all - so you haven't done anything to the water column apart from let water fall out of the bottom, eg you shouldn't have altered the tension in the elastic band (whether the elasticity is due to water stretching or the tube deforming) as you haven't changed the size of the weights on each end... did you pull the ends out of the demi-johns by lifting the whole apparatus or just the ends of the tubes?

ps.  by the way my calculation above was considering the force from the whole earth on the hydrogen atoms in a water molecule. Perhaps I should have said that on a molecular scale the earth's gravity is a very small force.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/05/2005 14:43:04
So even if we calculate the whole length of the tube at 48 metres, that still does not address the half metre rise in the water level on both sides of the tube, when they are lifted out of the bottles containing the water.

Zero water runs out of the tubes at the bottom, as you suggest might be the case. The water is sucked up inside the tube equally by the negative tension placed on the bead of water.


 
quote:
Your tube is pretty rigid, but if you squeeze it really hard I expect it will deform a little bit, you would only need a 5-10 percent deformation to cause a .5m movement in the water. Are you using the flexible clear PVC tube or the translucent white much more ridgid stuff?


Yes, it’s the rigid translucent stuff! The softer walled tube will simply neck )( under the negative tension. This rigid stuff does not neck and therefore the diameter internally will not reduce as a result of the negative tension. If I were able to squeeze it and alter its shape, it still would not alter the volume, as in order to do this one would have to compress the tube equally from all directions and this would take a huge force.


 
quote:
Hang on a minute - do I understand you correctly in that the bottom half metre of the tube empties and is full of air, and then stops?


It empties, but empties upwards!

 
quote:
Have you done anything else other than removed the demijohn? because just removing the demijohn will not alter the pressures at all - so you haven't done anything to the water column apart from let water fall out of the bottom,


No water falls out of the bottom until the bead of water cavitates!

 
quote:
eg you shouldn't have altered the tension in the elastic band (whether the elasticity is due to water stretching or the tube deforming) as you haven't changed the size of the weights on each end... did you pull the ends out of the demi-johns by lifting the whole apparatus or just the ends of the tubes?

Just the ends of the tubes!
Not quite correct Dave, there has been a reduction in the weights, because the water in the two bottles has been disconected, and thes do have considerable weight. Consider the water in the bottles as part of the mass of water inside the tubes and you begin to understand how trees draw water and mineral from the surounding soil into their roots, or into a cut stem or trunk, with no roots.



 
quote:
ps. by the way my calculation above was considering the force from the whole earth on the hydrogen atoms in a water molecule. Perhaps I should have said that on a molecular scale the earth's gravity is a very small force.

I think you still might be wrong with this way of looking at gravity. Try thinking of gravity as being a huge force capable of holding everything in homeostasis.


If there are any lurkers, please feel free to join in with this conversation.

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 02/05/2005 15:23:43
quote:
Yes, it’s the rigid translucent stuff! The softer walled tube will simply neck )( under the negative tension. This rigid stuff does not neck and therefore the diameter internally will not reduce as a result of the negative tension. If I were able to squeeze it and alter its shape, it still would not alter the volume, as in order to do this one would have to compress the tube equally from all directions and this would take a huge force.

An ellipse will have a smaller area than a circle of the same perimeter (think about how a toothpaste tube works), so you can reduce the volume of a tube by squashing it slightly, without compressing it from all directions.

quote:
Just the ends of the tubes!
Not quite correct Dave, there has been a reduction in the weights, because the water in the two bottles has been disconected, and thes do have considerable weight. Consider the water in the bottles as part of the mass of water inside the tubes and you begin to understand how trees draw water and mineral from the surounding soil into their roots, or into a cut stem or trunk, with no roots.

I am afraid you can't consider the water in the bottles as hanging off the tubes, the way fluids behave is to do with pressure. so as long as the demijohns are not sealed  the pressure at the surface of the water is atmospheric. The pressure will increase as you go down the demijohn, but it will reduce as you come back up the tube, so inside the tube, at the bottle water level the pressure will be atmospheric.

So if you pull the tube out of the bottle, unless the level of the end of the tube is different to the level of the water in the bottle nothing has changed.

Did you lift the tubes up or down when you removed the tubes?


quote:
I think you still might be wrong with this way of looking at gravity. Try thinking of gravity as being a huge force capable of holding everything in homeostasis.

I am not sure what you mean by homeostasis, as it is not in the oed and the only definition I can find is that it is a biological system that is stable due to negative feedback. Some systems acting under gravity are stable due to negative feedback - eg water in a glass is stable, but to say everything acting under gravity is under negative feedback is ridiculous - there is no way that a cricket ball in the air is going to be held in position... I am confused by what you mean.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/05/2005 18:00:39
Sorry, I did not make myself clear about the requirement of compressing the whole tube equally. I was relating to the negative water causing the tube to collapse equally, as this would be the case with a liquid under tension. Not at all like a finger and thumb compressing it.


 
quote:
Did you lift the tubes up or down when you removed the tubes?


An ellipse will have a smaller area than a circle of the same perimeter (think about how a toothpaste tube works), so you can reduce the volume of a tube by squashing it slightly, without compressing it from all directions.


If the tube was collapsing,” as you state the case might have been", then there should have been a noticeable rise in water level of the two bottles as the tube was hoisted up the cliff. As the bottles were filled almost to the brim on elevating the tube, the only bottle to begin overflowing was the one with the saline solution in it. When no salt is added and the loop is raised, there is almost no alteration in the bottle levels, indicating tube collapse to be minimal if any.

 
quote:
So if you pull the tube out of the bottle, unless the level of the end of the tube is different to the level of the water in the bottle nothing has changed.

Did you lift the tubes up or down when you removed the tubes?

Lifted them up and out of the bottles and let them dangle in the air.

quote:
I think you still might be wrong with this way of looking at gravity. Try thinking of gravity as being a huge force capable of holding everything in homeostasis.


 
quote:
I am not sure what you mean by homeostasis, as it is not in the oed and the only definition I can find is that it is a biological system that is stable due to negative feedback. Some systems acting under gravity are stable due to negative feedback - eg water in a glass is stable, but to say everything acting under gravity is under negative feedback is ridiculous - there is no way that a cricket ball in the air is going to be held in position... I am confused by what you mean.
[/quote][/quote]

ho·me·o·sta·sis (hm--stss)
n.

The ability or tendency of an organism or a cell to maintain internal equilibrium by adjusting its physiological processes.
The processes used to maintain such bodily equilibrium.

fits ok with this paradigm and discussion on trees and plants?

Your cricket ball is in the air, because gravity holds the atmosphere in place, and it will eventually come back to earth and its ultimate resting place, due to the inevitable effects of gravity, no matter how hard you throw it.

Just like a nuclear explosion is brought back under control by gravity

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 03/05/2005 16:58:02
quote:
Sorry, I did not make myself clear about the requirement of compressing the whole tube equally. I was relating to the negative water causing the tube to collapse equally, as this would be the case with a liquid under tension. Not at all like a finger and thumb compressing it.

Think back to how the soft tube collapsed when you first tried it, it will neck - go flat. This is because the cross section can reduce in are by changing from a circle to an ellipse - Under a vacuum the stiff pipe will turn into an ellipse slightly, but be strong enough to not actually collapse. However if the level of water didn't change in the bottles the collapse wasn't very significant.

However if the water was stretching then the water level in the bottles should increase as you pull up the tubes too... I am not sure what is happening with the water going up the tubes, I expect that there is something subtle going on with exactly how you are doing the experiment as I don't think either of our explanations work.

Out of interest what happened when you took only one tube out of the bottle?

quote:
ho·me·o·sta·sis (hm--stss)
n.

The ability or tendency of an organism or a cell to maintain internal equilibrium by adjusting its physiological processes.
The processes used to maintain such bodily equilibrium.

fits ok with this paradigm and discussion on trees and plants?


Not really, a force doesn't necessarily move a system towards an equilibrium (look at how the moon keeps falling towards the earth), a system may be designed to maintain an equilibrium.
You have to look at how the system is set up to find out whether it is stable or unstable

ps The cricket ball is in the air because I threw it there not because of the air - if I throw a ball up in the moon it will be up...
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 04/05/2005 09:03:35
The soft tube collapsing at relatively low elevation levels during the bench top experiments does not reflect the properties of the tough nylon tube now used. It simply will not collapse unles it is heated, which it is not during the experiments.

RE: taking one tube out of the bottle. There is a huge difference in taking the tubes out at a relatively low height. I.E. below the 33 feet limit. When tubes are removed at this height there is a siphoning effect that can be initiated. When over the 33 feet limit, the whole experiment behaves differently, in the the water will now remain suspended in the tubes, rather than flowing out as one would expect to happen. So I guess the elasticity of water does not significantly increase under the 33 feet limit.

Incidentally, I cant remember what happens when one tube is removed as it is usually removed when the bead of water has broken and the levels returned to 33 feet with vacuum above the levels. So I can't honestly answer this question, but will test it next time I use the experiments.

with regards to your other point on the levels not changing significantly as the tube is raised.
One possible explanation for this is that the tube elongates, due to the weight of water plus the weight of the nylon tube maybe.

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 04/05/2005 10:17:53
If that is the case the stability of the bead is an interesting effect to do with syphonish things, as this would require the bead of water to be somehow attached at the top...  although I would like to see the exact setup before being sure.

Maybe next time I come home to visit my parents I could pop over to Paignton on my way back to the train and have a look?

However even if this is the case your setup isn't a good model of the structures in a plant and even if it was it wouldn't explain the majority of what is happening due to energy concerns.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 04/05/2005 10:52:42
Dave, when I came to you In Brixham, I asked if you would be in a position to repeat my experiments. After visiting your website, I believe you are in a better position to do this than anyone else, with your connections at Chaossience.
I Would like to ask, if you would consider taking this experiment to your next demonstration, and I would be willing, (wrong word) Delighted to come and offer assistance, and provide your team with the tubing, etc.
How do you feel about this?
Respectfully   Andrew K Fletcher

http://www.chaosscience.org.uk/pub/public_html//index.php?topic=Events&menu=Events_
From your site:
Our events normally take the form of a room full of experiments each with at least one demonstrator, getting people involved and explaining what is happening.
We also run and help with various other events in Cambridge and will go into local schools


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 04/05/2005 12:07:02
I would want to understand what was going on really well before taking it anywhere near kids, boiling lots of water is a hassle and we don't often have anywhere which is over 10m high in the venues...

I would be interested to see it though.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 04/05/2005 12:13:57
A spiral staicase is a great place to conduct the experiment and many schools have several floors, presenting ideal locations.

The boiling water is not a problem as this can be done at home, taking the cool pre-boiled water along for the experiment. I even take along the coil of tubing, pre-filled with the boiled water and the saline solution in the centre, as this saves time at the School. But more water can be taken along for repeating the experiments.



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: NakedScientist on 09/05/2005 18:26:47
I'm going to move this thread to the 'cells' forum shortly, so look out for it there...

TNS
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 10:30:21
Why are you moving the thread? As this is a physics discussion, Can you please enlighten me why you believe it belongs on the cells forum?

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 10/05/2005 14:11:29
Although most of the discussion has been on physics, the question is actally biology, and a lot of the evidence is microscopic.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 14:31:21
I beg to differ David, None of my experimental models are microscopic. And yes, most of the discussion is on physics. The movement of fluids, fluid dynamics.

A Decisive Step: 1889–1924
The crucial period for our current views on the mechanism of water transport in plants were the years between 1889 and 1896. As a cornerstone we have a monumental book, Eduard Strasburger´s Über den Bau und die Verrichtungen der Leitungsbahnen in den Pflanzen (On construction and function of the conduits in plants) written in 1891. Strasburger, who is mostly remembered for his outstanding contributions to plant cytology, gave an encyclopedic compilation of old and recent work done on pathways and mechanisms of water transport in the plant body. As Sir Francis Darwin stated in 1896: "It is difficult to praise too highly this great effort of Strasburger´s".

Strasburger himself was an adherent of the school of physics and provided some strikingly efficient demonstrations of water being lifted to considerable heights without any involvement of living cells (Figure 1). He showed that woody stems with their lower end immersed in concentrated solutions of copper sulfate or picric acid and severed by a cut made below the surface of the liquid, will readily suck the solution up. Immediately upon contact, the poisonous fluid kills all living cells in its way, but the copper or the acid arrive in the transpiring leaves and kill them as well. The uptake of the solution and the loss of water from the dead leaves may continue for several weeks, and new solutions of a different color may be lifted in a dead stem.

http://www.plantphys.net/images/ch04/we0401a.png


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 10/05/2005 14:39:04
We have been through this before, but this is true of the xylem and water will be drawn up a dead tree, but not of the Phloem which is a complex bi-directional sugar and mineral transport system, not the downwards only pipe that is needed for your theories.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 15:28:38
There goes your precious leaf generated tension theory.

All of the cells were killed by the acid / copper sulphate solution. All of them! That means the phloem and the xylem. Yet the flow to the leaves remained functional for 3 weeks. Explain that using the cohesion theory!

There goes any connection whatsoever with living plant cells.

All we are left with is some dead inanimate tubular conduits and pits, “sounds like my tubular experiment more than some wonderful mystical suction from dead leaves”? Add some salts at the top of the tree from the decay / breakdown of the leaves, which will alone generate flow according to my theory.

 I know, I have repeated the experiments with liquidised leaves, tea, milk, urine, etc etc. anything denser than water will initiate this flow and the sooner scientists accept that this flow will occur wherever there is a denser solution above a less dense solution the better.

But to hide this thread from the view of people who are interested in physics and fluid dynamics is nothing short of censorship at best!

The truth of the matter is that this new paradigm looks a damned site more likely than anything that has gone before it! And it has already generated a lot of interest.

Are you afraid that it is becoming too popular? And feel the need to suppress it  by confining it to the cells, behind bars so to speak?

This theory is innocent and should not spend one night in the cells!
Andrew K Fletcher  


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 10/05/2005 15:39:07
Andrew

With physics it is always a good idea to keep an eye on where the energy is going,
So just answer me this...
98% of the water that goes up the tree is evaporated, so for every 100kg of water going up the tree at the most 2kg of water comes back down.

lifting 100kg of water 100m takes 10 000J

dropping 3kg of water and sugar 100m releases 300J

where does the other 9700J come from?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 10/05/2005 15:51:05
quote:
But to hide this thread from the view of people who are interested in physics and fluid dynamics is nothing short of censorship at best!

...and *that* is nothing short of paranoia at best.
It is a slightly odd feature of this site that it doesn't have a more general "plants" section but no-one doubts that your results physically occured in your tube experiments, that the weight of the solution is causing the flow.
Anyone interested in how plants work will be interested in cells too, and will be looking at that part of the website too.
If you're that worried you could always post a new thread solely about the physics of your demos... maybe even with a little more explanation of how your ideas accord with things like the principle of conservation of energy (unless you're ruling that out too? I haven't worked that out).
You could even explain the principles by which (on about page one) you reckon you can get water at the top of your loop given that the water in it must be a negative pressure.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 16:22:31
The beauty of this simple experiment is that it shows circulation of fluids through conduits. Inside the dead tree that is still lifting water and evaporating it from the leaves, all we have is the knowledge that circulation must be taking place because the leaves are still  transpiring moisture and that has to have come from the soil!

If only 1 gram of denser saline solution was returned in either a xylem or a phloem, this circulation would effortlessly lift / circulate many thousands of times its own volume, providing the tree with ample water to continue its evaporation. However, when the tree has been killed, the production of sugars will come to an end eventually and the minerals will find their way down to the lower part of the tree, ending the circulation at the end of the three week period, leaving only heat generated density changes to continue.

The cohesion theory needs to show this erroneous one-way lift of water. My theory requires the water to circulate. If you could set up the experiment you would see how important this is.

1 gram triggers this flow, never mind 2kgs.

Yesterday evening at 11.25pm, I set up an experiment with a 4 metre length of tube, open at both ends and filled with boiled water. At the time I am posting this, no cavitation has occurred, meaning that the water inside the tube requires only that the tubes be held in a vertical position, as they would predominantly be if they were inside a tree. This alone raises a serious question about your energy analogy.

So unless you are referring to the 10 000J as the suns energy, it does not relate to the experiments. 1 gram can cause many thousands of times its own volume to circulate vertically, and this will inevitably cause horizontal or diagonal circulation, depending on the route with the least resistance.

All that is needed is to show how the water circulates. Note the word circulates, as it is important. The term lift relates to your current line of thinking.


quote:
Originally posted by daveshorts

Andrew

With physics it is always a good idea to keep an eye on where the energy is going,
So just answer me this...
98% of the water that goes up the tree is evaporated, so for every 100kg of water going up the tree at the most 2kg of water comes back down.

lifting 100kg of water 100m takes 10 000J


dropping 3kg of water and sugar 100m releases 300J

where does the other 9700J come from?



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 16:28:50
Rosy, you don't have to be a genius to see that the cells forum is hardly visited by anyone, wereas the general science section is visited by most of the people who use the forum.

Nevertheless I thank you for seeing the logic in the experiments and for not doubting their validity as viable repeatable experiments.

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 10/05/2005 16:33:56
You are right you can cause lots of water to circulate without using much saline in your experiment, this is because you are not increasing the average height of water in the system - the energy required to lift the water on the up side is exactly the same as the energy released  dropping the water on the down side. You are just moving it from one bottle at the bottom to the other.  This means that all the weight of the saline has to do is overcome friction.

However a tree is not circulating at least 98% of the water!!!

98% of the water going up the xylem leaves from the leaves (you quoted this figure several pages ago) it isn't coming back down so the energy to lift it up is not released by water going down the tree.

So where is this 97J/kg coming from in your model?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: NakedScientist on 10/05/2005 17:10:43
Oh, alright then, I'll move it to Physics instead !

TNS
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 17:29:02
I have tried to convince you that the diameter or even the number of upward flowing water beeds does not equate to the volume of water or the diameter of tube in the return flow.

I have stated before, that you can have a larger bore tube on one side of the loop and a smaller bore tube on the other side, the balance is equal and the water is held in suspension.

I have tested this using a twin tube on one side and a single tube on the other, at 3 metres height. The balance on both sides is equal with no net flow either way. Only when a tiny amount of salt solution is added to the single tube side, or for that matter the double tube side does the circulation begin.

At the top of the tree the bore sizes change as the branches taper of to twigs, meaning that the return flow will inevitably be in a smaller tube to start with. As the water evaporates from the fine bore tubes, it is left with the return flow being directed down tubes of a similar size, or if that pathway cause back pressure, the flow will find a new route, causing more tubes to form.

So if you can picture a large volume of water being drawn through smaller tubes and that this reduced but denser volume flowing down through the smaller tube is sufficient to generate the pull of higher volumes of less dense solution in larger or even multiple tubes rising up, it simply does not require the energy input you are presuming it needs to flow. All I keep asking is that you repeat the experiments, or let me repeat the experiments and you will see exactly what I am talking about.

Hand the experiment over to the people at your homepage and ask them to form an opinion about whether this is relevant to plants and trees. I have not yet failed to convince all that have witnessed the experiments.

You also mention about the heights that fluids have to continuously attain, if I am not mistaken by your post. There is another force at play in this experiment, and that is the increased head of water generated in the rising side of the tube. The Brixham experiment dos not exactly reflect the fact that all of the multi-conduits inside a trees structure are inside one big conduit, and the roots are not exactly open as my tubes are.
Enclosing my experiment inside a tube filled with water would produce a net increase in the head of water, showing how trees can grow higher than the original water levels. It also shows to perfection how dew exudes from grass in the morning and how water exudes from a cut stem, previously believed to be some mystical force generated by the roots, known as root pressure.


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 17:46:18
Chris,

Why does it have to be moved? We have agreed that it crosses the boundaries of Biology, Physics and even Chemistry.
It also crosses the medical and physiology boundaries, geology and palaeontology and even evolutionary boundaries.
If this is not general science then what is?

I would love to have a chat with you on the phone, if this is possible let me know. My number is: 01803524117
Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 10/05/2005 17:56:10
If you connect a large tube and a small tube together in teh way you suggest it will work, however water is not being gained or lost from the tubes, so the flow in litres/second will be the same in the big tube as the small tube, the velocity in the big tube will just be slower.

The down bottle fills up by the same amount as the up bottle empties doesn't it?

If the up pipe is 12mm and the down pipe is 6mm, to test this colour the saline red and the water in the up bottle blue you will see that when the red drops all the way down the pipe the blue will lift up about 1/4 as far as the saline drops. so you have lifted 4times as much water 1/4 of the distance as the saline dropped - so overall water has just moved from one bottle to another.

A tree lifts water to it's leaves ans 98% of it evaporates, your model lifts water to the top then all of it comes back down. The two are not equivalent at all!!!


I am the people at my homepage so that won't really help - and at no point have I argued with the results of your experiments just your interpretations of them, so doing the experiments wouldn't necessarily help, although I would be happy to come and see yours at some point when I am in Devon and not too busy.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2005 18:08:57
NO David, if the tree is killed and the flow continues for another three weeks, it definately is not the tree that is lifting the water!

But you are missing my point with regards to this flow in a tree. The very nature of the trees construction enables transpiration to take place. I would not even know where to start trying to make an artificial tree. But killing the tree and the water / sap inside it is still flowing for 3 weeks is a vertual artificial tree.

If saline solution were to be some how introduced at the top of the tree once it has stopped flowing after the three weeks, we should observe fresh circulation due to the initiation of said flow and return system. Obiously, we would have to refil the tree to its previous levels of water to replace the losses from the falling levels of water inside the tree.

Give me a date, and I will drive to Cambridge and give a demonstration for all to see.

Andrew



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: moth on 11/05/2005 10:07:08
Andrew, I too met you in Brixham with CHaOS (yes we are ganging up on you ;-), so have had some time to think about your idea.

I believe your experiment works, but i mostly disagree with the conclusions you draw from it and the arguments you use to explain it. I also disagree with your dismissal of the other princples involved.

I imagine that there could exist a tree which transpired very little, but instead used your salt-siphon principle to create a vertical conveyor-belt of water to transfer chemicals between its roots and leaves. Dilute solution would rise up one set of tubes while an equal flow of denser, more concentrated solution would fall down another set of tubes, and at either end living cells could maintain the concentration difference by extracting solutes at the bottom and injecting them at the top. I'm sure this does some violence to a biologist's understanding of trees (and i know it doesn't match mine), but as a physicist i am happy with it in principle.

I consider it an interesting and clever idea, but don't believe it has much to do with how real trees actually work. The key flaw is that the salt-siphon cannot explain transpiration. Your idea requires almost equal up and down flows, while transpiration means that (vastly) more water flows up than down.

You rubbish root pressure, saying that if it worked then jets of water would squirt from the roots of felled trees. I don't think that follows. Water is almost incompressable at the pressures we are discussing, so it is entirely possible for the roots to contain water at a significant pressure without causing them to squirt when cut as the water would need to expand only a tiny amount to completely relieve the pressure. What i would expect as evidence for the existence of root pressure is for roots to gently ooze liquid for some time after they are cut. Indeed this is what i have observed: when I have cut limbs from trees during the spring and summer i have often seen liquid flow from around the edges of the wounds (where the current year's phloem and xylem are). To be clear, i'm not prepared to swear root pressure is all there is, but i don't find you dismissal of it convincing.

Osmosis is a complex, subtle and powerful phenomenon. It is quite possible that the widespread explanations of it are faulty, and yet osmosis really happens. I found this paper which discusses the many ways of analysing osmosis: http://arxiv.org/abs/physics/0305011

Your recent answers to Dave's questions about the energy budget refer to differing sizes for up and down tubes. This is strikingly similar to a perpetual motion machine I invented when i was 14. It works like this: construct a siphon from a short fat tube and a long thin tube connected at the top. Place the bottom ends in buckets and fill the system with water. As there is a greater weight of water in the fat tube it will pull water up the thin tube, so transfering water from the lower bucket to the higher one. I hope you can see why this doesn't work, and why your replies don't answer Dave's question.

I don't buy your dismissal of the 'conected water column powered by evaporation at the top' idea, but i want to do some calculations before i post on that subject.

You seem to attack most things simply by saying they are implausible. This is not an argument that holds any weight with me. If you want any acceptance of your idea you will have to start making sense in terms of accepted scientific priciples. Our discussion in the E=mc^2 thread suggests that you are not prepared to do this, but i still hope you will. It is as if we are speaking different languages. I have not managed to learn yours from your postings here, so if we are to be able to communicate you must learn mine.

I would be interested in seeing your experiment, but even if it works exactly as you say it does it wont change my opinions of your explanation of it. Mostly i am just curious about the details of your method, and would rather see it for my self than through your discription.

I suggest this thread remain in General Science - the subject is a mix of biology and physics with a hint of chemistry. The discussion has lacked biologists so far and could certainly benefit from their input, but while Dave and I continue to examine the physical basis of Andrew's theory it would be out of place in the Biology section.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 11/05/2005 10:53:07
One other point I would like to add is that if the Brixham experiment was inside the trunk /sleeve of a tree, it would be able to support the column to much greater heights, furthermore it would add another interesting force to the equation. It would generate an increase in the head of the dilute solution, picture an inverted U tube with clean water on one side and a small amount of concentrated solution in the other, the water levels will change, pushing the dilute solution up and out of the opposing tube, and the resting place of each side of the fluids level will be much higher in the dilute side than the side with the salt added.

This is the mechanism for water to exude from a cut stem and this is why it has been erroneously attributed to root pressure!

I look forward very much to showing you the experiments.

Andrew


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 11/05/2005 11:34:23
I believe that if you cut a stem right off (at the right time of the year) it will exude sap - I know a dandelion does, wouldn't this preclude your explanation as you have just cut off your inverted U tube?

I don't think that root pressure allways explains the whole pressures involved (apart from anything else if it is being powered by osmosis it is an energy intensive process and would waste a lot of sugar if it were used it for transpiration), but it certainly exists.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 11/05/2005 11:52:06
Ill be AFK for a few days, will catch up when I come back home.

RE: Tubular differences, try to see that the increase in tension of the fluids pulling the sap through ever smaller tubes, forcing the excess out through the leaves as transpired pure water. The forces generated by the falling solutes in other areas of the tree are more than enough to cause water to be drawn up and evaporated.

Remember also. When I first came up with this theory all those years ago, I did not have the Brixham Experiment to show the principles. In fact the experiment was built to show the forces and flow rates generated by this liquid pulley system \ Not siphon effect.

At the time, I also believed in the thirty three feet limit, but gave the experiment a go anyway, believing that the cohesive force in the experiment would easily exceed the adhesive forces in the capped tube experiment previously used to determine the height that water can be drawn up with a pump, as in Galileo's problem at The Grand Duke of Tuskany's Palace.

As I carefully drew the water beyond the 33 feet limit, I knew in my heart that this was and is a very important part of fluid mechanics and fitted beautifully with my hypothesis. When I added the salt to the one side to see if it would draw water from one bottle to the other, over the thirty three feet limit, I was ecstatic to say the least.

My colleague,  Adrian VanZweden, who was top in Physics at his University In Holland and had worked for many years as an water engineer at South West Water, sat on a step with his hands on his head shaking it, saying this is not possible, This cannot be happening, after previously stating that the experiments could not work according to current Physics literature. Adrian and I have conducted the experiments many times, and he was there also at the Brixham experiment, along with John Russell, pictured in the news article with my wife Jude.

Moth, thank you also for seeing the logic in leaving the thread in the General Science section.

Sincere regards

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: thedoc on 11/05/2005 14:02:35
Maybe we should derive a new forum...

MAD SCIENCE
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: anthony on 13/05/2005 04:24:32
The majority of scientific publications in this area appear to be in "Plant Physiology", "Journal of Experimental Botany" and "Tree physiology" I suggest you try either the British Library or a local university library to read these journals.

I don't have much time available to me but have found an interesting abstract on the topic, that represents something close to the "state-of-the-art" currently in the field. I think you'll be surprised at how advanced the field is.

Thermodynamic analysis of the interaction of the xylem water and phloem sugar solution and its significance for the cohesion theory.     Lampinen, Markku J.; Noponen, Tuula.    Laboratory of Applied Thermodynamics,  Helsinki University of Technology,  Finland.    Journal of Theoretical Biology  (2003),  224(3),  285-298.

Abstract

The cohesion theory explains water transport in trees by the evapn. of water in the leaves (transpiration), which in turn generates the tension required for sap ascent, i.e., the flow of pure water from the soil through the root system and the non-living cells of the tree (xylem tracheids) up to the leaves.  Only a small part of this water flow entering the leaves is used in photosynthesis to produce sugar soln., which is transported from the leaves through the living cells (phloem) to everywhere in the tree where it is needed and used.  The phloem sieves are connected to the xylem tracheids by water transparent membranes, which means that the upflow of pure water and downflow of sugar soln. interact with each other, causing the osmotic pressure in the sugar soln. (Munch model).  Here, the authors analyze this interaction with a thermodn. approach and we show that some open questions in the cohesion theory can then perhaps be better understood.  For example, why under a quite high tension the water can flow in the xylem mostly without any notable cavitation, and how the suction force itself depends on the cavitation.  Minimizing Gibbs energy of the system of xylem and phloem, we derive extended vapor pressure and osmotic pressure equations, which include gas bubbles in the xylem conduits as well as the cellulose-air-water interface term.  With the aid of the vapor pressure equation derived here, we est. the suction force that the cavitation controlled by the phloem sugar soln. can generate at high moisture contents.  The authors also est. the suction force that the transpiration can generate by moisture gradient at low moisture contents.  From the general osmotic pressure equation we derive an equation for calcg. the degree of cavitation with different sugar soln. concns. and we show the conditions under which the cavitation in the xylem is totally avoided.  Using recent field measurement results for a Scotch pine, the theory is demonstrated by showing its predictions for possible amts. of cavitation or embolism from morning hours to late afternoon.

Your argument on this website has been interesting and some excellent scientific points have been made about your theories and experiments by very talented scientists. However, they are not experts in the field and I think you might benefit from that input. The first two journals I mentioned are, most probably, peer-reviewing journals, which means that, subject to the editors decision, the editor may also be an expert scientist, submissions will be reviewed by two experts. If you are serious about your ideas I suggest you submit your experiment and theories as a what is known as a "letter" or "communication", this may need be no longer than one side A4. You should first read the journal for style and think about reading the literature to reference your work relative to that of others. I think a day or two reading these journals may be very fulfilling for you. It is not necessary to have a university address to get published, but your submission must be professional and new.

If you were prepared to write a manuscript, and place the text online here, I would be prepared to comment on style, and I suggest others might too.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 13/05/2005 18:06:30
Anthony: I have read very much all that has been written on this subject, including the cohesion theory, which, as shown in the abstract, does begin to attribute some force from the solutes to the picture:


The phloem sieves are connected to the xylem tracheids by water transparent membranes, which means that the upflow of pure water and downflow of sugar soln. interact with each other, causing the osmotic pressure in the sugar soln.

Now I wonder where the idea of sugars causing what is believed to be osmotic pressure, originated?

I have approached many journals to get my work published, only to find a very tightly closed shop.

1.   New Scientist. Dr David Concur was the Editor when I first approached them to publish my findings. He said if I can get one academic involved in either physics or biology to back me on this discovery, He would break with traditions and primary publish my work. I got quite a few people to back me and he went back on his word!
2.   I approached New Phytologist, only to find the same “Not invented here syndrome”. Got some encouraging letters and no logical reason for refusing to publish.
3.   Nature, Well, They would not give me a reason for not publishing. Nor would they offer any help for a new author as one would expect from such a well read journal. They did say that it was not fit for their journal in either format or content?
4.   The Lancet, relating to the massive amount of work I have done with neurology, helping people to regain a huge amount of function and sensitivity in people suffering from a whole range of neurological disorders, ranging from multiple sclerosis to spinal cord injuries. The Editor was genuinely interested and we exchanged a fair bit of information, including some amazing case histories, yet, they refused to publish also.
5.   And there are many more attempts to obtain publication like this. In fact, I have one investigation into Plagiarism ongoing at the moment on another subject.

I wish to say thank you for your offer to help me achieve the correct pitch for publication and will do everything I can to get this important discovery into the public domain.

I wrote to The Association of Science and Education to get the basic theory into their School Science Review Journal. They claim to have lost my paper, even though it was submitted electronically to several people in the same organisation. They blamed it on the Editor leaving and deleting my work? I have since been asked to resubmit it. They have been looking at this article since the year 2000.

Someone on here called me paranoid. I would say realistic in the face of everything that has been done to stop me from publishing.

But I will pick myself up;--no matter how many times I am kicked in the teeth while I am down and have another go.

As I see it there are two ways of protecting ones work. One is to tell no one and the other is to shout it from the rooftops, so that in the event that some thief tries to claim it as their own, they will inevitably come un-stuck, thanks to the Internets amazing capacity to record and date stamp almost everything discussed on the Internet.

There are many more open Journals available now online, which are putting a tremendous amount of pressure on the closed shop journals. In fact they are squealing like stuck pigs about the amount of published papers that are going to these journals, and the beauty of these journals is they are open for everyone to read the publications and free of any charge for the privilege of doing so.

I accept your offer to help me to publish and cannot thank you enough for your offer to help.

I believe the basic theory, which was written for School Science Review, is a good place for us to start.

Professor H.T.Hammel has said that he would help with the paper, maybe I could invite him to join the forum. Also Professor Michel Cabanac from University Laval, Quebec Canada has expressed an interest in this discovery.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 13/05/2005 18:39:04
quote:
Now I wonder where the idea of sugars causing what is believed to be osmotic pressure, originated?

What is this supposed to mean?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 13/05/2005 18:47:22
The phloem sieves are connected to the xylem tracheids by water transparent membranes, which means that the upflow of pure water and downflow of sugar soln. interact with each other, causing the osmotic pressure in the sugar soln.

How do you interpret this?

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 13/05/2005 20:21:54
You give the impression of not thinking that osmosis has any effect... and of doubting wheter it exists.

I think the abstract was coming up with a mechanism for how the Pholem can be at a positive pressure throughout it's length which is how the sugar can move through it with minimal use of energy.
http://employees.csbsju.edu/ssaupe/biol327/Lecture/phloem.htm

It is really neat - areas of the phloem with high sugar concentrations will draw in water from the xylem by osmosis so increasing their pressure. Areas which are using sugar have a low concentration of sugar and therefore a low osmotic pressure. Water flows away from regions of high pressure to the low pressure where the sugar is being used. This has the advantage of being able to move the sugar from where the sugar is being produced - either in the leaves most of the season, or from starch in the roots during the spring, to where it is needed.

I don't know whether I have acces to this article because I am in a university, but if you can I would defnitely read the introduction.

Link to article (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WMD-4938KWR-1&_coverDate=10%2F07%2F2003&_alid=277042368&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6932&_sort=d&view=c&_acct=C000053194&_version=1&_urlVersion=0&_userid=1495569&md5=e9327294e2e5df0e0a65559cf160c550)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 14/05/2005 09:52:01
Dear Doctor Saupe,
 
I wrote to you in April 2003 in order to explain a new paradigm in water movement in trees and plants. I never did get a reply and wonder if you would care to join our discussion at the Naked Scientist forum?
 
I believe your knowledge in this field would benefit this discussion immensely. I do understand that your commitments and demands on your time are high.
I hope you can find the time to look us up, as I believe we have a mutual interest in understanding the true functions of transpiration and water movement in trees.

Sincerely  Andrew K Fletcher


 

Last post on this topic:

 
quote:
You give the impression of not thinking that osmosis has any effect... and of doubting whether it exists.

 
Sorry for giving the wrong impression about osmosis. I believe that the accepted interpretation of osmosis is erroneous, as did Professor H.T.Hammel. Water cannot attract water to the leaves of a tree, any more than diffusion or root pressure can cause it to flow at the observed rates evident in trees! There has to be a method of loading an unloading sucrose as Stephen Saupe Suggests in his pages. The bulk flow rates observed in trees are undeniably massive and simply cannot be addressed by osmosis, capillary action, or root pressure! Saupe points to this problem in his pages. He also states that the phloem is under a positive pressure, demonstrated by aphids. This fits with my own experiment in the saline loaded side that does indeed flow down! He also states that there must be a sink. In my theory, I have mentioned the sink as being the roots and trunk for simplicity. There are also the fruits, leaves and minor branches that continue to grow providing additional sinks as Saupe also states.
 
Sauppe also states:
Bidirectionality - how can phloem translocate materials in two different directions at once? It can’t, at least not within the same sieve tube. However, presumably sieve tubes within a single vascular bundle could be transporting in opposite directions assuming each is acting appropriately.
 
The fact is that bi-directional flow in one tube is easily observed using my model, proving beyond any shadow of doubt that it will also occur inside a tree when the resistance in other pathways becomes congested!
 
I wrote to Stephen Saupe in Early January 2003, sending him information about my experiments. I never did get a reply.
 
XIII. Why does transpiration occur?
A. Transport in plants. This is important to a small degree. Transpiration is certainly not a necessity.
B. Heat loss (latent heat of vaporization)
C. Carry nutrients in the soil to the plant
D. Perhaps plant cells need to maintain some optimal level of turgidity and this helps them do so.
 
And lets not forget the picric acid and copper sulphate experiments killing all living cells in the tree and yet it still flows and transpires for three weeks post death of the tree.  
 
I am surprised that he has failed to realise the importance of transpiration, density and gravity.
 
I have written to Stephen Saupe again to see if he will join us.
 
Andrew



Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 14/05/2005 12:08:14
The probelm with osmosis is.....


http://arxiv.org/ftp/physics/papers/0305/0305011.pdf
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 14/05/2005 17:17:45
Your link to a paper was not in any way arguing that osmosos is empirically wrong, or that the way that thermodynamacists explain osmosis or it's properties was wrong, just that the simplifications that are taught to school children are a bit dodgy - so it is still a real effect !!!

I don't see why the bulk flow rates are not possible by osmosis - the rate of osmosis may be slow per unit area - but there are a huge number of xylem and their suface area is huge - so it all adds up to a big number - unless you can do soame maths to back up your argument it isn't very strong...

You didn't get my point about the Phloem - if it is all at an absolute positive pressure, if you wired one into the Xylem, theere would be flow of sugars into the xylem as the pressure is bigger there - THE WRONG WAY  - so if this is the case your theory can't use the Phloem as the downward path (especially as sugars flow up or down a tree depending on the season....) -  and I don't think there is anything else to use
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 14/05/2005 19:35:58
quote:
Originally posted by daveshorts


I don't see why the bulk flow rates are not possible by osmosis - the rate of osmosis may be slow per unit area - but there are a huge number of xylem and their suface area is huge - so it all adds up to a big number - unless you can do soame maths to back up your argument it isn't very strong...

You didn't get my point about the Phloem - if it is all at an absolute positive pressure, if you wired one into the Xylem, theere would be flow of sugars into the xylem as the pressure is bigger there - THE WRONG WAY  - so if this is the case your theory can't use the Phloem as the downward path (especially as sugars flow up or down a tree depending on the season....) -  and I don't think there is anything else to use



Not at all David, if you wired a positive force generated by falling sap it would find the most direct route to the ground. The flow works totally independent to pressures! You can pressurise a tube to a hundred bar and this flow would still travel down inside the pressurised tube. It does not require any pressure to function; it generates pressures as it functions!


When I did the exhibition in London, I used a saline drip feed to enable many people to see the experiment, which was repeated well over a hundred times.

To do this I needed to set up an artificial bladder, which was on a T junction as you suggest, but at the bottom end of the tubes, to act as a sump for the saline pulses which eventually reached the lowest point. This worked remarkably well, enabling the pulses of saline solution to replace the clean water in 2x connected bladder wash bags, representing the kidneys on either side of a Catheter bag which had a convenient drain tap right at the bottom acting as the ultimate sump, and representing the bladder in human physiology which of course enabled us to empty it. This worked perfectly except for the formation of gas bubbles in the upward flowing side.

Some very large bubbles collected at the upper part of the somewhat complicated tubes, which looked a little like a tubular maze. The interesting thing with the bubbles is that the flow continued around the outside of the bubbles and it did not stop the flow.

Another interesting observation for people at the exhibition was that if the drip bag was allowed to flow a little more profusely, the large bubbles at the top of the experiment began to travel down with the saline flow, some of these bubbles measured 10 millimetres long in a 4 mill bore soft walled tube.  One other point was that the bladder bag on the saline free side of the nighttime catheter bag emptied as the negative pressure caused by the downward flow pulled clean water into the system.  Now the thing about this experiment is it was a closed loop system, and that the saline flow had to be the principle cause of the negative pressures and positive pressures generated. Pressure from the drip feed did not make any difference because there was a convenient method of isolating it.

But the gist of this reply is, that gravity will drive this circulation, and your T junction will not alter its course, because it is not pressure dependent, and is not trying to overcome gravity as with the embraced cohesion theory. This flow system actually requires gravity and therefore negates your previous energy equation, which after all still relates to gravity as being a force to overcome.


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 15/05/2005 00:06:51
Regardless of what Chris may say about your bladder theories, you didn't understand what I meant:

The Phloem is at a positive pressure - this means that even at the top of the tree the phloem has a pressure greater than atmospheric.

We have established that the top of the xylem must have a negative absolute pressure of several atmospheres.

The reason your syphon works is that because the saline is more dense than pure water  it pulls down slightly harder than the water side, so the pressure at the top on the downward side is a few mBar lower than at the top on the upward side, so water flows towards the upward side.

Now in a tree you have a Phloem at a pressure greater than an atmosphere and the xylem at a pressure of minus up to 10 atmospheres - there is no way you can make water flow into the xylem if they were attached to one another. you can't get water to flow against a 10 atmophere pressure difference without something else going on as it is a fluid and fluids flow from high pressure to low pressure... (if they are at the same height - which they are)

You can make osmosis produce this sort of pressure difference, but unless you are injecting mercury into the phloem, not how you are suggesting.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: anthony on 15/05/2005 06:10:13
Andrew, thanks for your reply, given your enthusiasm I would have been surprised if you hadn't already tried to publish. First of all, being published means lots of hard work, lots of time and inveitably rejections. Some of what is published shouldn't be and some of what should, isn't, editors try and do the best they can, the main advantage for the editors is that they always have much more than they can publish. The editors' main concern, with good reason, is the reputation of their journal, and the best way to loose that reputation is to publish bad science.

By extension, if I'm not surprised you've tried to publish, given the fact you haven't published, I suppose I am also not surprised you haven't. People in the arts have the same arrogance of people in the science. We think ours is the discipline that concentrates on logic, they think theirs is the one which concentrates on communication. I've found much of what you said very difficult to follow and given the fact that this argument has now reached about 40,000 words, the length of a short PhD thesis, it doesn't get any easier. So now you see why I made my offer. People say scientists speak a different language, I'm offering my services, and that of this forum, as translator.

All but one of the publications in which you have so far tried to publish are wholely inappriopriate for this work. New Phytologist was a good start, and I refer you to the list which I first posted. But you simply MUST read and understand what other people in the field have done first. Furthermore, you must not see it as potential plagarism. The sad truth is that ideas are very rarely new, and I'm sure your ideas are no different. What counts is working the idea, with a little proof, into something that someone else can have an idea with. That counts for you and me as much as it did for Einstein.

Science is now conducted by professional scientists, it's the 21st century. The time of the "Gentleman Scientist" is behind us, it's a concept I have some affection for, but will never be re-instated. The era of the Gentleman Scientist was one full of great cataloguers and makers of lists and trees in biology, geology and paleontology. Great observers who could see the connections between things. The physicists were developing the basis of modern science in laboritories, and by the end of Rutherford's time it was essentialy dead. Rutherford had PhD students and worked in a university after-all. Take no offence at this, but you are essentially a "living fossil." As such, you can be poorly adapted for the world at large.

As the abstract I posted shows, water transport in trees is very much the territory of the modern scientist. Modern science is built on layers of concepts each the foundatation for the next, that's why it takes six to eight years, undergraduate/PhD, to produce one modern scientist. Increasingly scientists have to draw on knowledge from different fields to progress. The abstract I posted for example, drawing on advanced thermodynamics, mathematics and computing to solve a simple biology problem. It is not easy, it is very, very difficult.

Everyone in this forum is trying to help but you are at a considerable evolutionary disadvantage. It remains possible for the Gentleman Scientist to publish, but you simply must research others work and communicate in the right way. It's our rules now. Alternatively you can withdraw from competition, which is ultimately the safer thing to do.

I remain true to my original offer, and make a second. If you are minded to look into other people's publications in the area, I will give you a list of journal articles that may get you started.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/05/2005 16:10:23
Anthony

Thanks for your reply

I have taken much of what you have said on the chin. Your defence of editors and Journals in an ideal world would be acceptable. I have a huge amount of correspondences from these and many more journals, which I intend to publish for all to see, so that everyone can make up their own minds about why these people have the audacity to place such controls on science. But there is a huge swing right now towards a different kind of journal, and this has revived my spirit somewhat. Whenever there is a new discovery in Science of significant importance, History tells us that it is seldom the establishments that deliver it. In fact it is usually the “fossils” that provide us with solid foundations.

I am surprised that you suspect I have not read other peoples papers. I have! I also have a great deal of respect for Professor H.T.Hammel, Professor Michel Cabanac, Pete Scholander, Galileo, Evangelista Torricelli, Eduard Strasburger, Is there really any point in regurgitating old papers, which will place demands upon the permitted space in our publication. Other than a briefer mention than those set out in the links provided below? I do realise that other theory’s have to be shown to be weaker than this one, but how much time, effort and space has to be devoted to this?

For an excellent history of the ascent of sap, read the following.
http://www.plantphys.net/article.php?ch=4&id=98


http://www.plantphys.net/article.php?ch=4&id=99
A recent synthesis of the main features of the CTT and the electrical analogy used for modeling water transport in the soil-plant-atmosphere continuum has led to a new approach to plant and tree water relations: the hydraulic architecture approach. This approach considers a plant, and especially a tree, as a hydraulic system. All hydraulic systems (dams, irrigation systems for crops or houses, the human blood vascular system) are composed of the same basic elements: a driving force, pipes, reservoirs and regulating systems. So described, the hydraulic architecture is a powerful tool to study the hydraulic characteristics of the conducting tissues under a whole range of natural conditions. Important questions subject to study with the hydraulic architecture approach include:


I repeat: Anyone that has ever witnessed these simple experiments looks in awe and instantaneously accepts that this is exactly how trees lift water at bulk flow rates.
Anthony,
I have to ask you to repeat at least the scaled down versions of these experiments, in order that it will clarify the text to the point that you will totally understand what it is we are dealing with here. A trip to the local aquarium retailer will provide you with the required tubes, junctions and T junctions, used to aerate fish tanks. While you may believe that you understand how this flow works at the moment, it is only when you see it work that the full implications of this discovery hits home.

You are sure that my theory is no different to what has been done before? Have you seen another?

How can you say this when every single paper has been trying to understand how everything living is struggling against gravity and trying to overcome gravity?
My theory embraces gravity as the power source that drives the fluids of all things living, As far as I know, no one has a theory that identifies how gravity causes water to flow vertically and effortlessly.

 
quote:
Science is now conducted by professional scientists, it's the 21st century. The time of the "Gentleman Scientist" is behind us, it's a concept I have some affection for, but will never be re-instated.


There is more than one way this statement can be interpreted. I believe that the professionalism of scientists has compromised science causing a considerable degree of stagnation in pure science. Everyone either is accepting what they read as fact or too afraid of rocking the boats for fear of being ostracised.

I believe you are quite wrong about this bubble of the closed shop being impregnable to outsiders. I believe someone may just come along with a pin and pop it, kicking science so far off its pedestal that a new breed of scientists will again immerge and science will again grow in leaps and bounds. I first heard this from a doctor on an Open University Programme who sated that Science is on a pedestal and that it is all B*******. Another scientist added that once it has been kicked off its pedestal, he hopes it will not fall so far as to become irreparably damaged, meaning I take it as losing all of its credibility. I think the programme was "The trouble with science"

Truth has an uncanny knack of turning round and biting us all in the butt, so telling it as it is, rather than as it isn’t sounds like a good standpoint.

I am not scared of a fight, and I can assure you that I don’t abide by Queensbury rules and have despatched a few hardened boxers from the ring on my travels. But I do consider myself as a fair and honest person. And maybe even a gentleman in the sense that you have implied it. As for a fossil, I see myself as a new generation of people who dare to disbelieve what is written and question everything and everyone, taking absolutely nothing for granted.

While engaging a pathologist on this same subject but in a different model if you get my drift, she said; “My god you have just dissected a body in front of me reassembled it and explained how it all works perfectly, and not even had to cut open a single cadaver.

 
quote:
Everyone in this forum is trying to help but you are at a considerable evolutionary disadvantage. It remains possible for the Gentleman Scientist to publish, but you simply must research others work and communicate in the right way. It's our rules now. Alternatively you can withdraw from competition, which is ultimately the safer thing to do.

And I really do appreciate being granted an opportunity to share my findings with people here!

 
quote:
It's our rules now

Interpreted, as I don’t appear to abide by the rules?

 
quote:
I remain true to my original offer, and make a second. If you are minded to look into other people's publications in the area, I will give you a list of journal articles that may get you started.


Withdraw from competition? Bahh, never knew how to be a quitter, but I can see that you are steering me into a rather complicated paper, which I believe may be the wrong way to go. I think it should be kept simple that even a scientist can understand it. Present company excluded from that remark of course, and I really could use some help with this.

One last point, almost a week ago I set up a 2 metre vertical loop of tubing filled with boiled water with the two open ends submerged in two bottles of water to test the stability of gas free water. It has remained unaffected and is still intact. I will try to leave it for three weeks as Strasburger did with his tree experiment in picric acid to see if the constant tension causes cavitation without any added salt to the one side as in the Brixham experiment.

Regards  Andrew


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 17/05/2005 13:29:37
I think that a gentleman scientist can still do useful work, but this is very dependent on the area. In subjects that are studying the way the world is such as parts of zoology, geology, medcine and especially psycology there is a lot still to do - and anyone can find a new rock, animal or herb, however if you are in an area that has been intensely studied, the pickings are a lot poorer.

 I would also say that the gentleman scientist is more likely to find an interesting experiment or new observation than come up with new theries of how the world works (again depending on the subject) as in parts of physics just understanding the evidence that you have to explain with your theory takes many years of work, let alone understanding the strengths and weaknesses of the present theories.

So essentially you are better off looking for new butterflies or rocks than rewriting   quantumn physics.

I also think you are hugely underestimating the awkwardness of many scientists, a lot of them are really not the kind of people to fit in and take part in a conspiracy. Making lots of scientists do the same thing is a bit like hearding cats...

As to your experiments Andrew I can easily explain them by conventional physics apart from a couple of observations.

The not syphoning above a certain height.
and
The water retreating up the tubes when you remove them from the bottles.

I don't think that your explanations explain these any better than mine could so I am interested.

Have you made any form of systematic study of these phenomena? What height does the tube stop syphoning conventionally? does the water retreat up the tubes if the tube is shorter, or under less tension, or was layed out at an angle rather than vertically?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 19/05/2005 19:58:35

So essentially you are better off looking for new butterflies or rocks than rewriting quantumn physics.

No thanks; I have no desire to go chasing butterflies, anymore than I underestimate scientists.

As to your experiments Andrew I can easily explain them by conventional physics apart from a couple of observations.

The point really is the original thoughts, which led to the experiments, and is now leading to a paper compiled in such a way that it is beautifully simple, yet addresses all of the known idiosyncrasies inherent in the current theories.
To say that you feel that you can explain them by conventional physics is comforting, as I would expect this new paradigm to be understood by physicists and biologists. After all, the children and teachers in the schools I have demonstrated the experiments in, had no difficulty understanding this logic, anymore than the 3 thousand visitors to The London International Inventions fair did in 1997.

What I do find surprising is that no one here appears to have conducted the experiments for themselves in order to give a qualified account of their own observations. If it is the money, I will send the £3.00 so that you can purchase the tubing and T junctions. This is even more confusing when one would think that with so many young enquiring minds someone at least would want to see water flowing up a tube for themselves.
 
Have you made any form of systematic study of these phenomena? What height does the tube stop syphoning conventionally? does the water retreat up the tubes if the tube is shorter, or under less tension, or was layed out at an angle rather than vertically?

Not sure about what you mean by a systematic study. I have tried removing the tubes at lower than the thirty three feet limit and find that water flows out of the tube from one side only, lifting the entire contents up one side and out of the other. This was demonstrated to the children at HighWeek Primary school in Newton Abbot, Devon. They had difficulty understanding why water only flowed out of on end when the tubes were lifted.

I have tested the tube at an angle, a loop, partly horizontal and partly vertical, in an intricate multi directional set up, and it works the same. I.E. a flow and return is observed! But this is hardly surprising when this same flow is attributed to driving the Atlantic Conveyor system (Gulf Stream) where there are no tubes whatsoever. Like I said before, it has no respect for where it flows. But flow it must!


I am also surprised that the link below did not generate much interest?

http://www-saps.plantsci.cam.ac.uk/search_links.htm
Gravity of Life - Have you ever thought how trees are able to transport fluids to their tops? Andrew Fletcher has some novel thoughts on how plants use gravity to drive this process.




"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 19/05/2005 20:36:55
Why is it that the phloem sap is observed to flow down, in the opposite direction to the predicted path of suction generated by the leaves? According to this theory, it is hard to understand how a plant or tree can differentiate between the xylem and the phloem. How can the same leaf suck up water in the xylem and blow it down the phloem at the same time? If you were to place an atomiser from a paint spray gun at the top of the tree, under say 65 psi, would you really expect this to cause water to be drawn up the tubes inside the tree? NO! It simply cannot work any more than a lift pump would work placed at the top of the tree. Why would you expect the current cohesion theory to work? You add, well there are many leaves at the top of the tree and the interactions between all of the leaves and the atmosphere would suffice to generate ample pull. How? There are many trees which have minimal leaves at the tops, like the larch which lift water with ease, yet do not have anywhere near the surface areas that you suggest would be required to generate the pull! Let alone Strasburger’s dead transpiring trees.

Even if you removed even more branches from the top of a larch it would carry on pulling water to the top! Look at bamboo for instance, or climbing vines.

A few days ago I went out with a stethoscope to listen to the trickling of sap as it flows in bulk within the trunk of an ash tree, which was just in bud. Again this tree did not have the massive surface area the cohesion theory requires of it. I could hear the water flowing and the cavitations creating cracking noises.

Now explain that with your knowledge of physics please,


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 19/05/2005 21:51:12
On the "Gentleman Scientist" question...
There is no particular reason, I don't think, why a "gentleman scientist" such as Andrew shouldn't be able to make and interpret accurately useful new discoveries many fields (I'd suggest that this wasn't infact the case in quantum physics which tends to require several miles of subterranean tunnels full of particle accelerators as this might be more than a little way outside the typical spare-time budget). It would require a phenomenal amount of dedication to get up to speed on the current thinking, getting hold of material not available on the internet etc., but some do have that.

However... the presumption within the scientific community is that individuals not doing this as a full-time job can't possibly have the time, energy and access to materials this requires, and so tend to be starting with an assumption that such people are unlikely to have anything very interesting to say. The primary necessity for anyone from an unexpected background who wanted to get their theory recognised by the scientific establishment is to write a *very* detailed explanation of their new theory along with a discussion of the old theory they're attempting to debunk which shows a very thorough understanding of the old theory such that it's impossible for readers to discount the whole exercise by saying to themselves "he only doesn't believe our theory because he doesn't understand it".
You haven't persuaded me yet. This may be because we're attempting to communicate in text and you haven't shown me any numbers, but I'm not convinced.

quote:
What I do find surprising is that no one here appears to have conducted the experiments for themselves in order to give a qualified account of their own observations. If it is the money, I will send the £3.00 so that you can purchase the tubing and T junctions.

Nope, not the money. The time. And the space. When I have more than a couple of hours together to call my own I have every intention of having a shot at some of your experiments. But as a student in a ground floor room in the middle of a seriously flat county this is not high on my list of priorities.

quote:
If you were to place an atomiser from a paint spray gun at the top of the tree, under say 65 psi, would you really expect this to cause water to be drawn up the tubes inside the tree?

I don't know how an atomiser from a paint spray gun works, but if it didn't introduce an air bubble or a nucleation site for a cavitation into the system I'd expect any given pressure to draw up a column of water of the corresponding depth... 1Atm vs a vacuum pushes water up 10m, as in a water barometer so my expectation would be that provided no cavitation occurs (and I'd suspect most conventional pumps in this area) a negative pressure of 2Atm would pull water up about 20m.

quote:
I am also surprised that the link below did not generate much interest?
http://www-saps.plantsci.cam.ac.uk/search_links.htm

Why? It's a links page... so you have novel theories about water transportation. We all know that.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 20/05/2005 00:26:26
quote:
Why is it that the phloem sap is observed to flow down, in the opposite direction to the predicted path of suction generated by the leaves?


Andrew fluid flows in the Phloem up down and sideways, it has been measured to be at a positive pressure - THIS MEANS IT CAN'T BE SUCKING UP THE WATER IN THE XYLEM DIRECTLY!! in order to suck the pressure in the phloem must be lower than the xylem..

If you read my previous post you would have found out that the reason it is at a higher pressure than the xylem is osmosis - the Phloem is sugary, and therefore water will osmose into it from the xylem. This can happen at pressure differences of 10-20 atmospheres quite happyly.

quote:
If you were to place an atomiser from a paint spray gun at the top of the tree, under say 65 psi, would you really expect this to cause water to be drawn up the tubes inside the tree?


If you made the atomiser out of something hydrophilic like paper or cotton and the holes in are small enough then yes.

Andrew HOW DO YOU KNOW WHAT AREAS ARE REQUIRED FOR THIS TO WORK? have you done any experiments or even calculations to find out - if so could I would be interested, if not please not don't make broad generalisations which you can't back up
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 20/05/2005 21:34:32
Dave

If you had read my previous posts, you would have found that this flow is not pressure dependent! It does not require pressure; it generates pressures as it flows! The tiny pulses of saline solution injected at the top of the loop experiment flow down. This causes a dragging effect because of the cohesive qualities of water. The downward flow cannot flow down without dragging water down with it. It behaves like an elasticised string. I.E. the downward flow is not possible, without it causing an upward flow! Phloem flows in the direction of a sink! If that sink happens to be an apple, then it will flow towards the apple, if it happens to be a root, it will flow to the root. If a denser solution is flowing down, then a less dense solution will be flowing up or in any direction affording less resistance! Hence “Flow and return”. In my inverted tubular experiment, both tubes are under a negative pressure with no saline added. Demonstrated by the water retreating up the tubes when the tubes are lifted out! Yet when the saline is added, it causes the contents of the whole tube to rotate in the direction of the downward flowing salt solution.

1.   Evaporation cannot take place without it altering the density of the sap at the leaf!
2.   Gravity will pull on the denser sap causing it to flow in the direction of a sink!
3.   The denser sap will drag less dense solutions from other areas of the tree!
4.   Pressures will be altered by this flow and return system, but the flow itself is not pressure dependent. I.E. Pressure changes are not required to cause this flow in any direction, other than the effect of gravity upon dense sollutions!
5.   The flow and return will generate negative pressures and tension in the sap at the roots and throughout the xylem it will generate an upward pull on the water, which will cause water to flow horizontal, down, up and diagonally, because the water is being dragged upon by the falling solutes and in the phloem it will inevitably change the negative pressure to a positive pressure, causing both a pushing force in front of it and a pulling tension behind it.
6.   In the tree, there is an outer sleeve, which adds additional support for this flow and return, making it much more robust than the simple inverted U tube experiment. Within this sleeve / bark cavitations can occur frequently and do not interfere with this flow and return system. The sap simply flows around the gas bubbles, as observed in my own tubular experiments.
7.   In these tubular experiments, it was also observed that a two-tier flow system can exist in a single tube, meaning, that there is a flow and return observed in the same side of a closed loop of tubing. Meaning, that a concentrated solution flows down one side of a diagonally placed loop of tubing, while clean water flows above it in the opposite direction!

For you to keep dismissing this as irrelevant to trees, without observing the hard evidence for yourself is a reaction I have grown to expect from people who would rather believe text in text books, than to question and evaluate the theories for themselves. You have absolutely no idea of the full implications. I have lived and loved my work and will do so until the day I die!

I therefore decline your polite invitation to become self gagged and hope you will understand why.

Andrew


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 21/05/2005 00:21:57
Andrew Yes your system generates it's own pressure differences however the water is still moving because of pressure differences they are just generated by density differences not by a pump..

 Shall we do a little calculation...

if you inject 20cm of saline with a density of 1.5g/cm3 this will produce an extra pressure of about (1000kg/m3-1500kg/m3)*.2m*9.81 = -1000Pa or -.01Bar above the saline on the downwards side.

So for a little overview:
The pressure at the top of a 20m tube
on the no saline side is -1Bar
on the saline side it is -1.01Bar because of the extra weight of the saline pulling on it.

This means that at the top the pressure on the saline side is lower so water moves towards the saline side - as you have observed.


However if you measure the pressure of the fluid in the Phloem
http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=440496&pageindex=1
you find the pressure is positive and up to 10 Bar - (otherwise aphids would implode)

So lets think about this -

the pressure in the xylem is at up to -10Bar the pressure
in the Phloem it is at +10 Bar.

Now you are expecting me to accept that the water is moving against a pressure difference of 20Bar to flow into the Phloem with no Osmosis going on...?

quote:
For you to keep dismissing this as irrelevant to trees, without observing the hard evidence for yourself is a reaction I have grown to expect from people who would rather believe text in text books, than to question and evaluate the theories for themselves. You have absolutely no idea of the full implications. I have lived and loved my work and will do so until the day I die!

Please do not say that I am ignoring the hard evidence - at no point have I said that  there is much wrong with your experiments - they are exactly what I would expect to happen apart from a few minor details that you have not investigated in detail.

What I am disputing with you is your interpretation, as although on the surface it sounds nice if you had bothered to do any simple calculations - like how much energy is released by the sap going down compared to the 50x more water going up, looked at the actual structures in a plant, considered what the pressure is in the Phloem, considered that sugar flows in more than one direction in a plant, etc. you would have realised that unless a tree is a perpetual motion machine, and is not designed the way it appears to be it can't work the way you describe.

The most important question I have to you despite all this, is have you ever considered that you may be wrong? or prefereably tried to proove yourself wrong. As if you haven't you are not doing science but PR.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/05/2005 11:28:23


Inside a phloem, the structure adds an additional restrictive force on the downward flow, mainly friction, causing the falling solutes to back up, “Hydraulic brake”, slowing the flow down, and allowing sugars and salts to accumulate, giving rise to higher pressures. Inside the tree, as previously explained, there is additional support for the columns of water, due to the outer sleeve of the tree. This will inevitably explain the reductions in negative tension found inside the tree, as opposed to those that are obvious inside the Brixham Experiment. For instance, If I were to use a closed loop of tubing instead of the open ended tubing in the Brixham Experiment, then the height that can easily be obtained would exceed even the tallest of trees, and the circulation generated by the solutes would effortlessly rotate the fluids in the direction of the density path. Again the support of either a closed loop or a semi-closed loop changes the pressure parameters greatly.

In your calculations, I have difficulty understanding how you have derived the figures.

I believe you will find that the negative tension inside the inverted U tube at 20 metres will be far higher than your estimate. And as you are aware, the experiment is designed to demonstrate the flow, not to mirror the internal structure of a tree. So comparing like for like with the inverted tube is pointless.

See Reference to Professor H.T.Hammel letter page 2 of this thread.


 
quote:
The most important question I have to you despite all this, is have you ever considered that you may be wrong? or prefereably tried to proove yourself wrong. As if you haven't you are not doing science but PR.


With this last question, it would appear that you are trying to belittle me. Why is this? Do you not think that given all of the years I have been working on this, I have not tested and re-tested as to whether I am correct or incorrect?
E.G.
One simple test for you:

Measure the density of your urine, making a note of what you have eaten and drank during the day. Retire to bed, and measure the density of your urine when you relieve yourself in the morning.

Now elevate your bed by no less than six inches or fifteen cm’s at the head end and repeat exactly as the day before.

Then sleep with your head down and your feet up on the same incline and do the same. Now compare the figures and explain why there are massive differences in urine density.

Also, if you have varicosity in the lower limbs, you might find that the veins are pulled in by the reduction in pressure inside the veins, as we did when sleeping with the head end elevated for four weeks. Strange, because the vein in my wife’s leg had been bulging and aching for 16 years, following the birth of our first child. The vein is no longer varicose and barely visible!

You will find that your heart rate will reduce by 10 to 12 beats per minute, and your respiration rate will reduce by 4-5 breaths per minute, even if you are a sleeping bull terrier! But you will need a partner to measure these while you are sleeping.

Most of my research since discovering this flow and return has been directed towards helping people suffering from a whole range of illnesses. Like I said before, this flow and return has no respect for where it flows, but flow it must! I have spent many years working with and helping people with neurological and non-neurological conditions, to which, I have never charged a single penny for my services.

However, discussing this physiology and its wide ranging relationships will only serve to complicate this discussion beyond the purpose of plants and trees, and I have absolutely no wish to do so, other than offering this as an excuse for not conducting a greater number of various experiments with water and tubes. I have found myself going full circle and addressing the foundations of the initial discovery, which is to show how the bulk flow is generated, how it circulates and how evaporation triggers it.

As for P.R. I have appeared on television 3 times, been featured in the Daily Mail, Western Morning News, BBC and independent radio, Woman’s Realm magazine, Herald Express, Sunday Independent, Disabled Bikers Magazine, Medical Physics Group Newsletter at The Institute of Physics. Why would I want to be doing P.R. on the Naked Scientists forum? I find this remark of yours a little terse.

I am here because I am trying to understand what is required of me to publish a paper that will provide the “Closed Shop Scientific and Medical Communities with a paper that is difficult for publishers and readers to ignore, and believe it or not, I am gaining a tremendous insight into how this is to be achieved. And perhaps enlist a little expert help.

Andrew


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 23/05/2005 13:13:56
I'm not saying which is the right interpretation of the urine density experiment, but my first interpretation would be that if you sleep with your head raised it makes breathing easier, which means you sleep more deeply.
When you sleep you produce more of the antidiuretic hormone which controls water loss (or possibly re-uptake, I forget) in the kidneys, so that you lose more urea etc. and less water. I suspect (I fear there aren't any physiologists reading this thread, so I'll have to check it on the physiology forum) that if you sleep more deeply you produce more ADH and therefore urine is denser.
Which would mean that the result would be due to gravity, but rather due to an effect on snot than on blood.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 23/05/2005 13:26:36
quote:
I believe you will find that the negative tension inside the inverted U tube at 20 metres will be far higher than your estimate.

Atmospheric pressure will support a 10m column of water. This will give a vacuum pressure above the water (0Atm) We know that. (I think?)
Atmospheric pressure is about 10^5 Newtons per square metre.
Pressure due to gravity changes linearly with depth in a liquid. In a column 10m high which is in an open jar at the bottom will have a point 10m up where the pressure is 0 bar. You've established that water may but need not cavitate at negative pressures. If it does not then there must be a "pull" from above to support the extra weight of water in the column and the decrease in pressure continues linearly to be -1 Atm at 20m, -2 at 30m, etc, until caviatation occurs and the whole lot falls back to the 10m it can sustain without negative pressure.
The -1Atm pressure at 20m means that there is a pressure difference at that height between the outside atmosphere and the water in the tube of 2Atm or 2*10^5 kN per m2.

By the way, if you've had time to think about getting water out of your inverted tube at the top, which you reckoned a while back you could if you wished design an experiment to do, I'd still be interested to hear about it (or any time you do get time to consider it!)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/05/2005 14:35:30
Rosy
Actually, you sleep less deeply with the bed inclined, rem sleep is less frequent, dreaming becomes far les frequent. The body generates a substantial amount of additional heat in the inclined position, avoiding the temperature drop off that horizontal sleep causes. More heat = higher evaporation, which inevitably results in the production of denser urine.
Head down tilt on the other hand produces urine of near water density! Which at least proves that renal function requires gravity in order to transport solutes through to the bladder. Head down tilt temperature also fits with the temperature reduction in hibernating bats, and as it is used to simulate the harmful effects of micro-gravity on astronauts, it has ben thoroughly investigated, with huge amounts of literature available on the internet.




"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 23/05/2005 16:15:38
Isn't REM sleep an indicator of light sleep - deep sleep happening in between the episodes of REM/dream sleep?

It may indicate that renal function is assisted by gravity, but it certainly doesn't proove gravity is required for solutes to be moved to the bladder. If it was the whole story then astronaughts would be dead after a few days in space...

It is possible that a lot of sleep problems could be assisted by altering the angle of the bed - this will have lots of effects like altering snoring, altering how hard the heart has to work, which will have lots of subsequent effects... the human body is a horribly complex system so making niave conclusions from simple experiments is a little dangerous
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/05/2005 10:58:00
Rosy



 
quote:
Atmospheric pressure will support a 10m column of water. This will give a vacuum pressure above the water (0Atm) We know that. (I think?)


If you are referring to the barometer type experiment, the only reason the water remained in the tube was because of the ability of water to stick to the top of the capped tube and the friction to the internal walls of the tube, again adhesive (adhesive quality of water) Atmospheric pressure does contribute to the experiment but not as much as believed, demonstrated by the inverted U tube, which relies on the cohesive force of water, more than doubling the height achieved and therefore indicating that adhesion was the principle factor in the barometer type experiment. When the water level goes below the 10 M level in the Barometer type experiment, it is then supported by a vacuum.

In the Inverted U tube experiment, there is twice the weight applied to the column of water suspended over the raised middle of the tube, and therefore twice the amount of tension is applied to the water inside the tube, yet it remains relatively stable providing the gas has been removed from the water by pre-boiling it.

The pull from above is balanced by the equal opposing pull on the opposite side of the tube, which therefore is a not actually a pull from above, more an increase in tension.
Again atmospheric pressure plays a part but not as much as previously thought. More, the Cohesive strength of water is tested against the adhesive strength of water + the additional friction caused by the additional adhesion to the doubling of the length of tube compared to the single vertical tube.

I conducted another experiment at 2 metres elevation, This involved 3 lengths of tube connected to a central T Junction, one length was longer than the other 2, to allow the open end to be doubled back on itself into a U shape, again with the end open and the water level inside to be at the same level as the water level in the jug which contained the other two open ends of the triple conduit. The U ended tube was allowed to fall below the water level in the jug containing the otehr two open tube ends ends. The whole experiment was filled with pre-boiled water and great care was taken to make sure there were no leaky joins where air could be sucked in.

What would you, or anyone else reading this expect to happen to the water in the end exposed to the atmosphere via the U shaped exit point, and the central T junction was elevated to 2 metres vertical?

With regards to constructing an experiment to show that water can be excreted from a tubular construction, Strousburger already did it by killing the tree and observing water transpiring from the leaves for three weeks after the death of every living cell in the tree, making the trees tubular structure a perfect example of your challenge! And in doing so concluded that bulk flow was not a living process, but a Physical non-living process! I am tempted to repeat his truly fascinating experiments myself.

Andrew



"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Terry Richards on 26/05/2005 12:54:37
I have been reading this thread and thought I might add that I was at the London International Inventions show in 97 and saw the experiment on display at Andrew’s stand. It was remarkable. From what I remember he had a dark red coloured liquid, which was salty water and dye in a simple loop of tubing suspended on a board with bags. Although I didn’t fully understand the explanations he gave, the water did appear to be flowing up and down.

He was showing a bed that was tilted. I didn’t stay to the end of the show to see if he won anything for his invention, but the experiment was impressive.

Terrence
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 26/05/2005 22:09:16
Andrew, I hope I'm about to explain some things you already know. But it's not at all clear from your posts that you do understand this stuff. I'm not going to consider the effects of introducing different densities of liquid, because that merely confuses the issue.
I don't think you should be disagreeing with me on any of the points I make here.

The basic point about a liquid such as water is that the pressure at a given depth is constant for any interconected bodies of water (where each is free to flow into the other.
So if equal pressures act on both side of a U tube open at both ends, the water in the two tubes will be at the same level.

If we then take out some of the air on one side (say reduce the pressure to half an atmosphere) then the water on that side will be pushed through the system by the air pressure on the other side until the system is balanced again. At this point, the pressure in the water on the other (lower pressure) side, at the same level, will also be 1 Atm. This will be due to (i) a pressure of 0.5 Atm from the gas and (ii) an extra weight of water, which will be enough to give 50kPa per square metre (as water weighs in at 1000kg per metre cubed, so a metre depth of water exerts a pressure of about 100N per square metre=100Pa) so the depth of the water will be 5m higher on one side than the other for a 0.5Atm air pressure difference.

quote:
When the water level goes below the 10 M level in the Barometer type experiment, it is then supported by a vacuum.


This is entirely untrue. The water is not supported by the vacuum in a barometer, it is pushed up by air pressure at the water level of the open vessel which gets it up to a height of 10m under compression. The vacuum cannot provide *any* force on or against *anything* because THERE'S NOTHING THERE, it's just a total absence.

Up to 10m, nothing has to be supported under tension *at all* because it's all happening at positive pressure.

quote:
In the Inverted U tube experiment, there is twice the weight applied to the column of water suspended over the raised middle of the tube, and therefore twice the amount of tension is applied to the water inside the tube, yet it remains relatively stable providing the gas has been removed from the water by pre-boiling it.

Um, no. In an inverted U-tube less than 10m in height there is no tension at all, it's all happening under positive pressure, just less than atmospheric. There's quite a large difference between the two [1] (provided there's no other way of air at atmospheric pressure seeping into the system). The pressure in the two tubes at any given depth will be the same. If there is space for it to do so, the water wants to move from high to lower pressure, which is how a syphon works- if pressure is 1Atm at a point on one side of the system and at some open point lower down on the other side there will be a positive pressure greater than 1Atm at that point. In which case, if it is open to the air, water will be pushed out of the system against the 1Atm pressure.
Above 10m, provided no cavitation occurs, the same will apply. Pressure falls constantly all the way up, and negative pressures "pull" exactly the same in all directions... against the walls of the tube, against neighbouring "bits" of water and so on.

quote:
Strousburger already did it by killing the tree and observing water transpiring from the leaves for three weeks

My point is that I think that your demonstration system requires more weight coming down than going up (weight of water plus weight of solution). This is very obviously not true of a tree and doubly untrue of Strousburger's dead tree which is no longer synthesising sugars.
If you can't build a demonstration then an account of a back-of-an-envelope calculation accounting for the energy and mass transferred (what's going where and what's powering it) might serve equally well to convince me.

quote:
What would you, or anyone else reading this expect to happen to the water in the end exposed to the atmosphere via the U shaped exit point, and the central T junction was elevated to 2 metres vertical?

I have no idea... I don't understand your description. Any chance of a diagram?



[1]100kN per square metre is about equivalent to 10,000 kg. The oft-quoted comparison for this is that it's equivalent to the weight of one elephant per metre cubed.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/05/2005 23:21:40
Terry
Thank you so much for the post Terry, Smiling like a cheshire cat here :) Though probably won't remember you from the exhibition :( Was a great few days for me, my son and my friends who attended. I did win a Thousand pounds worth of free advertising in Streetwise Magazine and there was a nice feature in there about the experiments and theory behind the bed design.


Rosy
A simple thought experiment for you to consider Imagine the inverted U tube experiment set up, but this time, the two open ends are submerged in one sealed container, with the water level afording some air space above it. And it has all the pressure removed eliminating any positive pressure or influence from the atmosphere.

Prediction, the water column will remain intact. What do you think?   B.T.W thinking about a way of testing this one to settle an argument.

In the case of the barometer type experiment, "Thought experiment again unfortunately" removing the poitive pressure in this experiment by sucking the air out of the beaker containing the water with the open end of the capped water filled tube will indeed cause the water to be pulled from the top of the capped tube at a much lower height than ten metres. But this does not prove that the pressure was the only force supporting it. It suggests that the increased downward force of the water has severed the hydrogen bonds to the capped glass tube.

I was trying to refer to the way a syringe pulls water up, even when there is air space directly in front of the plunger. The absence of pressure if you like is sufficient to draw water up acting upon its surface, so why do you think the vacuum is any different to the suction caused by the plunger in a syringe?

Maybe its the way I explain it?

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/05/2005 23:44:38


Rosy

I forgot to add that Strasburger's experiment (killing the tree) caused a cascade of solutes to flow down from the inevitable decay of the foliage and internal cells. According to my theory this would be more than enough to cause the flow and return to carry on for three weeks or more. The solutes did not vanish suddenly along with the death of the tree, they remained at an elevated point and were released slowly. I think Strasburger may have even noticed an increase in the circulation of the dead tree during the rapid release of stored sugars and salts.

I really don't relish killing a tree for science to test this, being a tree hugger by nature, I like planting trees not destroying them.

If i purchase a digital camera and video the experiments would this be acceptable to you and others? Seeing as no one can be bothered to repeat them. I have the original Brixham exp on video also, maybe I can find a way to load it on to a website.

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 27/05/2005 00:55:41
quote:
A simple thought experiment for you to consider Imagine the inverted U tube experiment set up, but this time, the two open ends are submerged in one sealed container, with the water level afording some air space above it. And it has all the pressure removed eliminating any positive pressure or influence from the atmosphere.


By eliminating any positive pressure do you mean carrying out the whole experiment in a vacuum? as otherwise there will allways be a positive pressure. You can't do this with open ends to the tube as it would cause the water to evaporate at the ends quite quickly...

quote:
Prediction, the water column will remain intact. What do you think? B.T.W thinking about a way of testing this one to settle an argument.


If you could somehow do it without exposing the surfaces to a vaccum and none of the surfaces were hydrophobic to act as nucleation sites it probably would remain intact - if you ignore the bottom 10m of your experiment that is essentially what you have done.

You could build your 2m loop and attach syringes to the end and pull on the syringes with a force of 100 000N x Area of syringe in square meters (so for a syringe with an area of 1cm2 apply a force of 10N or about 1kg. This would be equivalent to doing the experiment in a vacuum as the weights on the syringes should be compensating for atmospheric pressure.

As a check try it with and without a tiny bubble in the system, if when you add the bubble the weights pull the plungers out but when you don't have a bubble they don't, I think it has shown what you want to.

quote:
In the case of the barometer type experiment, "Thought experiment again unfortunately" removing the poitive pressure in this experiment by sucking the air out of the beaker containing the water with the open end of the capped water filled tube will indeed cause the water to be pulled from the top of the capped tube at a much lower height than ten metres. But this does not prove that the pressure was the only force supporting it. It suggests that the increased downward force of the water has severed the hydrogen bonds to the capped glass tube.


If you are using very clean and boiled water I expect that you could support a column higher than 10m in a glass tube, and I am sure it is possible using the tubes you do - as long as you can fill the end of the tube with no bubble or with something that has holes so small that sufrace tension can support the pressure - a tree.

  the ten metres thing does however hold if you are using large tubes with dirty and unboiled water as once there is a bubble the water will cavitate if there is a negative absolute pressure.

But this is all dead standard cohesion theory...

quote:
I was trying to refer to the way a syringe pulls water up, even when there is air space directly in front of the plunger. The absence of pressure if you like is sufficient to draw water up acting upon its surface, so why do you think the vacuum is any different to the suction caused by the plunger in a syringe?

The reason that a syringe can suck even with a bubble in it is that everything is under atmospheric pressure 100 000Pa - the equivalent of 10m of water.

so if the water in the syringe is under a pressure of 100 000Pa and the fluid in the syringe is under pressure of 90 000Pa there will be a NET force towards the syringe and liquid will flow in, without having a negative absolute pressure anywhere.

I think you will find that the syringe will not suck if there is a bubble and you are working against more than 10m of head - again you are in a good position to try this.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/05/2005 22:03:37
Dave, you have made some interesting points, and I have taken on board your idea about a syringe and a kilo weight. Great idea if the syringe can deal with a kilo force in the opposite direction to its designed function, but its certainly worth a try.

By the way, if the inverted tube is at 2 metres and the ends submerged in water at equal lengths, filling one bottle higher than the other causes it to flow to the other bottle as expected. From what I remember this was not the case at over the 33 feet limit. But I will have to test again at some point to make certain. Also, at 2 metres using the salt, it does not return to the other side because of the increased density of the salt receiving side. I have not observed the coloured salt solution flowing back up the tube once it has reached the bottle and the tube contains clean water. Also, you can regulate the flow by altering the density on the rising side bottle. This is important, because it suggests a mechanism for acid rain to kill trees by altering the density of the ground water by dissolving a greater amount of minerals from the soil. It should be easy to test this by adding salt solution to the soil, and then adding distilled water to compensate for the increased salt to see if it allows the plant or tree to recover. This also fits with overfeeding plants and killing them.

Thanks for the suggestions

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: daveshorts on 29/05/2005 12:04:31
Cool, just be a bit careful about the design of your experiment, as if you are attempting to distinguish between two hypothesies you have to be careful that the result will be difficult in the two hypothesies. I think adding a lot of salt to the ground would kill the tree in the conventional model as it would tend to dessicate the roots by osmosis...

Out of interest what do you mean by return to the other side? It is hard to describe this sort of thing without a diagram... Do you mean that in teh long tube the flow overshoots and then afterwards flows backwards for a bit?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/05/2005 19:52:56
I have drawn a diagram of the triple tubed exp, but can't figure out how to post a picture on the site, that on my hard drive :(

The last post was refering to the single looped tube exp.

According to the results in the single loop tube, it should only require a relatively small amount of salt to upset the flow, when added to the rising tube side. However, the tree has a fair amount of sugars and minerals in the sap and stored in the leaves, branches and trunk. So the salt may cause the leaves to wilt, but it may not kill the tree for a long time. just wandering if anyone has done something similar with trees and posted on the net?

Got my eye on a cannon Ixus 700, to film the experiments, but they cost over £300 with a decent memory card and tripod. But feel it will be well worth getting a good camera with high movie resolution.

It's about time I made a web page so I can store the pictures on it, tried using a blog, but the pictures still do not show on here for some reason.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 30/05/2005 10:48:22
Trees the key to beating salinity
DAFF04/175M 18 August 2004

The Australian Government's Natural Heritage Trust will invest $2.9 million over two years to develop commercial environmental forestry (CEF) that will address salinity.

Speaking at a regional forest investment workshop in Morwell, Australian Forestry and Conservation Minister Senator Ian Macdonald said the CEF program developed farm forestry systems that reduced salinity while delivering commercial returns.

"It is about linking the commercial to the environmental to develop long-term agricultural business options for farmers affected by salinity," Senator Macdonald said.

"When adopted, CEF will also benefit the broader community by not only reducing salinity in the Murray system, but also by protecting water quality and biodiversity. The CEF project supports private and public outcomes for regional catchment management groups and private investors to deliver benefits."

The CEF project began in 2003, and is a major collaboration between CSIRO and the Australian Government Department of Agriculture, Fisheries and Forestry. Other partners include the National Association of Forest Industries, the Murray Darling Basin Commission and the Victorian Department of Primary Industries.

The project partners will invest more than $4 million in 2004-05, and plan further investment in 2005-06.

The project is focussed initially on a pilot in the Goulburn Broken Catchment where salinity is a major problem, and the Catchment Management Authority (CMA) has targeted forestry as a potential solution. The CMA is an active partner in the project and is holding community forums to involve landholders.

The project has identified those areas in the catchment where forestry will reduce salinity without stressing river flows. These areas are typically found where rainfall and growth rates are lower than in traditional plantation areas. CSIRO is undertaking research to reduce investor risk by identifying species with commercial potential for these lower rainfall areas and developing growth predictions for them.

The project is also quantifying the other environmental benefits of farm forestry of interest to regional NRM groups and governments. These include biodiversity conservation, carbon sequestration and erosion control.

"This new funding of $2.9 million comes on the back of initial seed funding of $550,000 provided last year," Senator Macdonald said.
http://www.mffc.gov.au/releases/2004/04175m.html

Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. II. Flowering, fruit set and fruit growth.

H Howie and J Lloyd

Abstract
Flowering, fruit set and fruit growth of 'Washington Navel' orange fruit was monitored on 24-year-old Citrus sinensis trees on Sweet orange rootstocks that had been irrigated with either 5 or 20 mol m-3 NaCl for 5 years preceding measurements.Trees irrigated with high salinity water had reduced flowering intensities and lower rates of fruit set. This resulted in final fruit numbers for trees irrigated with 20 mol m-3 being 38% those of trees irrigated with 5 mol m-3 NaCl. Final fruit numbers were quantitatively related to canopy leaf area for both salinity treatments.Despite little difference between trees in terms of leaf area/fruit number ratio, slower rates of fruit growth were initially observed on high salinity trees. This effect was not apparent during the latter stages of fruit development. Consequently, fruit on trees irrigated with 20 mol m-3 NaCl grew to the same size as fruit on trees irrigated with 5 mol m-3 NaCl, but achieved this size at a later date. Measurements of Brix/acid ratios showed that fruit on high salinity trees reached maturity standards 25 days after fruit on low salinity trees.Unimpaired growth of fruit on high salinity trees during summer and autumn occurred, despite appreciable leaf abscission, suggesting that reserve carbohydrate was utilized for growth during this period. Twigs on high salinity trees had much reduced starch content at the time of floral differentiation in winter. Twig starch content and extent of floral differentiation varied in a similar way when examined as a function of leaf abscission. This suggests that reduced flowering and fruit set in salinized citrus trees is due to low levels of reserve starch, most of which has been utilized to support fruit growth in the absence of carbohydrate production during summer and autumn.

Keywords: Oranges, irrigation, water, salinity, responses, fruits, set, development, flowers, initiation, Carbohydrates, metabolism, Polysaccharides, Flowering, growth, Maturation, subtropical fruits, citrus fruits, fruit crops, Citrus, Australia, Rutaceae, Sapindales, dicotyledons, angiosperms, Spermatophyta, plants, Australasia, Oceania, 2180,

Australian Journal of Agricultural Research 40(2) 371 - 380
http://www.publish.csiro.au/nid/40/paper/AR9890371.htm

Salinity and drought stress effects on foliar ion concentration, water relations, and photosynthetic characteristics of orchard citrus.

JP Syvertsen, J Lloyd and PE Kriedemann

Abstract
Effects of salinity and drought stress on foliar ion concentration, water relations and net gas exchange were evaluated in mature Valencia orange trees (Citrus sinensis [L.] Osbeck) on Poncirus trifoliata L. Raf. (Tri) or sweet orange (C. sinensis, Swt) rootstocks at Dareton on the Murray River in New South Wales. Trees had been irrigated with river water which averaged 4 mol m-3 chloride (Cl-) or with river water plus NaCl to produce 10, 14 or 20 mol m-3 Cl- during the previous 3 years. Chloride concentrations in leaves of trees on Tri were significantly higher than those on Swt rootstock. Foliar sodium (Na+) and Cl- concentrations increased and potassium (K+) concentrations decreased as leaves aged, especially under irrigation with 20 mol m-3 Cl-. Leaf osmotic potential was reduced as leaves matured and also by high salinity so that reductions in leaf water potential were offset. Mature leaves had a lower stomatal conductances and higher water use efficiency than young leaves. After 2 months of withholding irrigation water, leaves of low salinity trees on Tri rootstock had higher rates of net gas exchange than those on Swt rootstock, indicating rootstock-affected drought tolerance. Previous treatment with 20 mol m-3 Cl- lowered leaf area index of all trees by more than 50%, and resulted in greater reserves of soil moisture under partially defoliated trees after the drought treatment. This was reflected in more rapid evening recovery of leaf water potential and less severe reductions in net gas exchange after drought treatment in high salinity trees on Swt rootstock. High salinity plus drought stress increased Na+ content of leaves on Swt, but not on Tri rootstocks. Drought stress had no additive effect, with high salinity on osmotic potential of mature leaves. Thus, the salinity-induced reduction in leaf area appeared to be independent of the Cl- exclusion capability of the rootstock and decreased the effects of subsequent drought stress on leaf water relations and net gas exchange.

Keywords: Oranges, salinity, responses, rootstock scion
http://www.publish.csiro.au/nid/40/paper/AR9880619.htm

Salinity

Cause

Salinity damage is caused by the accumulation of toxic levels of salts (sodium and/or chloride) in the tree. This usually arises from the use of saline irrigation water or the presence of a saline watertable within or just below the rootzone.

Symptoms

The severity of symptoms increases with the concentration of salts accumulated in the soil and/or trees. Loss of tree vigour is a major symptom of salinity. Trees affected by salinity generally show water stress before they should, ie when soil moisture content appears adequate. This is particularly the case where salt has accumulated in the soil.
Marginal leaf burn, particularly towards the tips, is characteristic of salinity. Leaves tend to be cupped. Premature drop of a proportion of the older leaves may occur along shoots.
When cut off, the branches of salt affected trees have discoloured heartwood.
In severe cases salinity causes tree death.

Control

Leaf nutrient analysis is a useful means of detecting the development of salinity problems. Annual leaf analysis will reveal the trend in leaf sodium and chloride levels. If levels are increasing the cause of this should be investigated. Bear in mind that higher levels can be expected in low rainfall seasons and in years of higher than normal river salinities.
The water used for irrigation in the Riverland is relatively saline, normally in the range 400 to 800 EC. With adequate irrigation management and good drainage, these levels of water salinity need not substantially affect stone and pome fruit production.
Leaching of salts through the soil profile is a necessary part of irrigation in the Riverland to prevent salt accumulation in the rootzone.
For further information refer to the irrigation section.



Knowledge of the problem?
Observations of increasing land and stream salinity were first reported many years ago. In 1907 Government Analyst E. A. Mann suspected that there was a relationship between clearing and the development of land salinity.

In 1902, 8,000 ha of trees in the Mundaring Weir catchment were ringbarked to increase run-off. Salinity in the weir increased, and in 1909 it was recommended that regrowth be encouraged and replanting undertaken. This was done and salinity levels fell.

Increasing salinity in railway dams used to supply water to steam engines was also observed. A railway engineer, W. E. Wood, collated and analysed the early data and with the publication of his paper in 1924 the relationship between clearing and increased land and stream salinity was unequivocally established.
http://agspsrv34.agric.wa.gov.au/environment/salinity/intro/salinity_at_a_glance.htm

Dave, this does appear to fit with the saline regulation of the tubular experiment, where the saline sollution isadded to the rising tube side bottle.

But more to the point, it was because of my interest in irrigating deserts and reforesting them that I considered how the trees were dealing with salts in the first place. I have contacted the Australian Government and several experts on desertification many times over the years, but failed to touch a nerve. Now trees are being recognised as valuable desalination plants.

This is good news for me. I have been shouting this message at them since 1993. "Plant Trees to reduce salinity in the ground water" I am curently shouting a similar message to the people in Thailand, who are experiencing one of the worst droughts in their History.
http://www.thaivisa.com/forum/index.php?act=Post&CODE=02&f=18&t=29285&qpid=358136


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: qazibasit on 10/06/2005 10:35:26
its mainly due to ascent of sap.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rabeldin on 28/06/2005 22:40:44
Mangrove trees, which grow in salt water, so something oppositee. They take in salty water and deposit salt crystals on the surface of their leaves. Surely, the difference in ion concentration is a crucial factor in both situations.

R A Beldin,
Improbable Statistician
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/08/2005 10:52:22
R.A. Beldin

Mangrove trees are able to restrict the amount of salt they take in and the salts found on the leaves are a result of evaporation, re-concentrating the salts. The difference in ion concentrations is indeed a crucial factor in all situations. Wherever a concentration takes place due to evaporation there is an obvious alteration of density in the fluids that are shedding water. There has to be! Denser solutes at the evaporation points will inevitably be acted upon by gravity and there goes that for every action there is a reaction again. Gravity will pull the denser solution down and the negative tension behind the falling sap will draw up less concentrated solution as a return flow, much the same as a flow and return system in a central heating boiler, which uses heat to alter density on the rising side and the cooled water becomes denser so provides the return flow. Having fitted this type of boiler it contributed to the discovery.  Flow and return hot water supply drawings. http://www.gasman.fsbusiness.co.uk/system_basics.htm http://www.ecoplusonline.com/images/Fig5_70.gif


"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: robbyn on 08/08/2005 13:10:42
I am interested to learn if there is more evidence supporting Andrew's view that it is best to sleep on a slight decline. Since 1998 is their further emperical evidence in support of the claim? Have their been any tests undertaken in controlled circumstances?

In his 1998 article he explains that "Cattle and sheep, when given a choice all sleep facing uphill". To me this reads as if they prefer to sleep on an incline.

Hospital beds in order to encourage sluggish circulation and avoid thrombosis are designed to raise the feet above, not lower them below, head level. I assume the benefits of this have been endorced by hundreds of years of practical observation.

Andrew makes some big claims  for sleeping on a decline of 5 deg. As the benefits claimed are considerable I would appreciate an update, so I can decide if I should copy it.

Robin
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/08/2005 15:22:00
Hi Robbyn

I have been trying to enlist the cooperation of the medical profession since 1994, lots of broken promises, despite having convinced quite a few people within the health service that this would save them an awful amount of money and time, not to mention saving patients limbs and lives.

I am currently trying to get a simple study with varicose veins oedema and leg ulcer underway at the local prison. The Health Officer there is very interested and we have the support of a vascular surgeon from Torbay Hospital and Professor’s Urnst and Curnow, also invoved with local health service and universities.

 The case histories are from my own attempts to demonstrate just how effective this simple cost free therapy is.

My telephone no is +44 1803524117 should you wish to hear this from the horses mouth, or have any questions which require answers.

Sincerely   Andrew K Fletcher

Below is a thread where I have been asking on here for some help to conduct a study that will be accepted by the medical profession.
http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=2262

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: robbyn on 08/08/2005 20:28:26
It seems there are two things to investigate:

1. The pumping action of a tree. Is it gravity aided?
Comment
I notice that you were invited to put together a page length paper for a peer reviewed journal. I would suggest you follow that advice.

2. The medical benefits of sleeping on 5deg declined bed
Comment
I have read the testimonials you kindly sent to me. They are remarkable and the results astounding. I can understand you wanting to pursue this discovery. It may be that the gravity theory does not account for the results. I am not qualified to comment. I know that many discovers of medical breakthroughs were broken by the system demanding explanations rather than results. I do not understand why bed manufactures are not happy to finance a study.


Robin
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Jason Fletcher on 10/08/2005 02:44:23
Its about time they started to give u some constructive comments dad! ive been watching these threads for a while now [:D]
I have watched and heard and seen thousands of people from doctors, proffesors, scientists to journalists and lamers on the net try to rip into my dad for years and try to take down his ideas and accomplishments and have all failed miserably .... he will get recognised in the end ya know!!! jus keep motoring on dad!!! .. why is it so easy to spread bad news and it is so difficult to bring a ray of light to the world?

Jason
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 18/10/2006 08:39:52
As we now have quite a few new members, it might be worth taking another look at this theory and hope you will forgive me for bumping this subject up.

Andrew

"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Wade on 11/02/2007 23:43:43
It looks to me like the answer would lie in the active transport of cells... and that if the tree is completely dead when the water moves upward, something is pushing it. perhaps it is the process of death and decomposition that pushes the water upward into the leaves, if, for instance, the circulatory pathways  harden and move water upward as they dry up. i admit, I only started researching tree circulation today, and except, of course, for photosynthesis, i have almost no knowledge of the anatomy of a tree, but i do know a significant amount about physiology and this entire topic seems to me like way too much energy put into something that could be found out with a little research. although i admit, i haven't read the entire topic either.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 24/08/2007 20:20:02


The Experiment at Brixham Overgang Cliffs where water flowed vertical up a single 6 mm bore tubing using 10 mils of salt solution, demonstrating that a tiny amount of denser solution can lift effortlessly many thousands of times it’s own volume in water without any artificial aids, demonstrating clearly a non living physical cause of bulk flow in plants trees, animals and humans. The 10 metre limit for lifting water clearly needs some serious revision.

Online experiment details
http://www.metacafe.com/watch/786493/water_flowing_up_a_cliff_to_24_metres_with_no_pump_experimen/#

http://www.myspace.com/inclined_bed_therapy
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 05/09/2007 19:08:40
http://www.metacafe.com/channels/AndrewKFletcher/

Just added the scaled down version of the Brixham experiment on metacafe and the set up instructions for the experiment as parts 1 and 2, followed by actual footage of the experiment in Brixham in 1995, seems such a long time ago now, particularly when the evidence provides irrifutable facts, one can't help wondering why it has been resisted for so long.

This short video shows how water is raised using salt solution it also shows negative tension pulling a filled syringe body plunger in. But most of all it shows the velocity of this flow system in realtime.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 21/09/2007 10:59:49
Rosy, have you seen the experiments on metacafe yet? Take a look at the scaled down version of the Brixham Experiment, here you will see a syringe filled with concentrated saline sollution being sucked up under a negative tension. The weight of the salt +resistance of the syringe body shows there is a negative tension in the water and the same happens without salt sollution. Mentioning this to advise you that your statement is not correct.
Quote
Andrew, I hope I'm about to explain some things you already know. But it's not at all clear from your posts that you do understand this stuff.

Up to 10m, nothing has to be supported under tension *at all* because it's all happening at positive pressure.



Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 21/09/2007 13:00:01
Sorry. It was a siphon in 2005 and it still is.
It still doesn't explain anything that wasn't better explained before.
And I have too little free time to go round the houses on this one with you. Again.

On second thoughts, I'm a sucker for an obvious explanation...

You have added n mL of a denser solution to your dilute solution. Say the density is 2 g/mL rather than 1 then thats added n g extra weight to the "down" arm.
All the water in the "up" and "down" arms is balanced from one side to the other so say your max tube height is 20 m and you inject 10 mL salt solution (weight 20 g), you've just aquired the ability *by siphoning* to lift 10 g, and therefore 10 mL water 20 m up. If the surface of the water under your your "down" arm were 1 m higher up than the surface of the water under your "up" arm I'd expect to see you siphon 200 mL water. If they're only 10 cm different in height it would be 10 times that, so 2 L water. If they were at the same height limiting factors would be things like friction as you're not actually lifting any water that isn't counterbalanced by water on the other side going down.
I can't see the heights of the containers on the Brixham cliffs experiment, but the scaled down version seems to show about 2 mL salt solution, so maybe 2 g of weight falling maybe 1 m, and two containers at near-as-dammit the same height (say 1 cm different), and maybe 3 mL water transferred across.
So you've got enough energy out of your SIPHON to move 2 mL water up 1 m (OK, maybe a bit less, depending on how concentrated your salt solution is) but you're actually lifting about 4 mL up about 1 cm, using maybe 2 % of the energy available from the conventional-physics based explantion in terms of a siphon.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 21/09/2007 16:48:36
Thank you for the reply Rosy, Ill try to get my head around your post in a bit, but the question that tension does not exist inside the inverted loop of tubing is dismissed because the salt solution is not initially injected into the tube but the syringe plunger together with the salt solution, which is hanging upside down is drawn into the loop of tubing by a negative tension which you said does not exist in your earlier post.

To activate this flow system all that is required is one grain / crystal of salt or sugar in one side, this induces the water filled loop of tubing to circulate. Even half a single crystal would do it. If you look at the other video showing salt crystals dropping into a clear water filled container you can see the flow generated by individual falling crystals as they dissolve, the sunlight shows the current created by this system.

there is no height difference between either of the bottles, the tubes are placed at the bottom of the two bottles. The recipient bottle overflows, the donor bottle level goes down rapidly as water is transferred from one vessel to the other, the displaced water = many times the volume of the added salt solution and should equate to the contents of the donor side of the tube. Which incidentally can be much larger in diameter than the downward flowing side. I have used an additional juxtaposed tube in the donor side to prove this capability and it runs perfectly. I did this to show that the flow is capable of delivering sufficient sap to the leaves to allow for the huge evaporation, which is known to take place at the leaf.

Changing the height of the arms as you put it at 24 metres does not induce a flow through siphoning. Possibly, the elasticity of water prevents this causing the bead of water to break and then water in both sides of the tube irrespective of the differences in levels will fall to the 10 metre level and the space above the water levels is vacuum.

This flow is different from a siphon effect. Because the water molecules are connected and under tension, by cohesion, the first denser molecule descends causing a chain reaction along the entire tube which drags all of the other molecules around much the same as if the water bead were made of elastic.
 
Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/01/2008 11:36:57
Umbrella Plant Experiment 
Cyperus alternifolius

Take a stem of this plant approximately 6-8 inches place it upside down in a beaker / vase of water and ignore for around 2 months. The roots begin to grow from the crown of the leaves, followed by the ascending leaves from the developing root crown. Gravitropism is the term used to explain how plants and trees determine the correct orientation in relation to gravity. However, I believe that the migration of denser solutes to the leaf crown due to the plant being kept upside down plays a very important part in this process.

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi209.photobucket.com%2Falbums%2Fbb31%2FAndrew_K_Fletcher%2FUmbrella%2520Plant%2FUmbrellaPlantExp002.jpg&hash=4932c25efbbd6af211c1da143f6b6622)
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Andrew K Fletcher
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: YourUncleBob on 29/04/2008 09:11:53
Andrew, Rosy and Dave, interesting dicussion, thought you guys might like to check out these papers on the subject of trees and osmosis.


http://arxiv.org/ftp/physics/papers/0305/0305011.pdf

http://www.fasebj.org/cgi/content/full/13/2/213#F4
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/04/2008 16:14:21
The paper Evolving ideas about osmosis and capillary fluid exchange  Ted Hammel is known to me, the other however is not. Thank you for the comment and glad you enjoyed the read.
Have you anything to add regarding points you have picked up on within this thread?

Kind regards

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: YourUncleBob on 06/05/2008 02:13:58
Andrew,
Apologies for my tardiness, been a bit busy as of late, I've been thinking about trees and their ability to lift water for a long time now.

I've been working with my material science students on creating an artificial tree encased in a glass-like sphere to lift water over 300 meters.

Our goal is to take energy from the sun in the form of heat to create electricity. Our basic design involves several of these 'trees' releasing the water they collect at the bottom of their glasslike domes into a central reservoir.Once the reservoir reaches a predetermined level, the water is released, passes through a turbine before being deposited in another reservoir under their 'roots'. This is a complete closed system.

Obviously there has been a lot of interesting problems to overcome!

But one of our biggest problems right now is getting the balance right between evaporation and solute concentration. The evaporation rate from our artificial leaves has to be such that the concentration levels of salt&sugar in our respiratory system don't get too dense and clog up the works!

I posted a question on this in the plant section but with no replies.


With regards to your experiments and whether or not there's a syphon effect I'm of the opinion that you've not created a syphon, as there doesn't seem to be any vacuum involved.

We've yet to test the fluid dynamics of a solute heavy liquid travelling down a 50 meter pipe (nevermind 300meter) into a pure water reservoir (where the pipe's 'skin' is semipermeable) then back up 50 meters.

Would the flow offset the 'osmotic push'?

Would we have fresh water pushing against the downward flow of the solutes?

Or would the two forces combine to provide some additional upward lift?

Your thoughts would be much appreciated.

Blaine
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/05/2008 22:17:09
My thoughts on this is rather than using a single large conduit is to use multi-conduits so that cavitations can be isolated.

I think you are shortly going to realise that osmosis might not be all that it is cracked up to be and that the flow and return system should provide the force. I cannot see osmosis push adding much if anything to the model. Reverse osmosis on the other hand where the pressure is obvious when applied on the other side of the model becomes logical and works efficiently in desalination of seawater. Maybe rather than raising the apparatus up we should be thinking about harnessing the density differences in seawater giving us a desalinated by product which could prove very useful. This is where I have been considering an application to lift sea water, remove some water by evaporation and collect it for drinking or irrigation and return the denser saline water back down the return flow giving us the capacity to turn an impeller and provide the force to return more salt water up the less dense side of the model. Alternatively just harnessing the depth of the ocean to generate electricity is something worthy of consideration.

Your tree model ironically represents much of what has been discussed on this thread and others over the years and I am glad that someone is investigating this simple paradigm further.

Thanks for letting me know about your experiments.

Kind regards

Andrew 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: YourUncleBob on 08/05/2008 04:21:36
Andrew your name keeps popping up whenever we use the internet to do research on this subject, so I feel honored to be sharing our thoughts with you.

Quote
My thoughts on this is rather than using a single large conduit is to use multi-conduits so that cavitations can be isolated.


Yes, that's exactly our plan with heavy solute pipes (Down) 10 times narrower than their corresponding low solute pipes (Up). Though we've included several bridges from the 'down' pipes to their corresponding up pipes, each bridge getting progressively narrower as we get closer to the bottom of the 'tree'. This was to help with any osmotic push, something I know you don't believe has much effect. We're counting on your 'gravity flow' to be aided by these 'little' osmotic pushes.

Your ideas of lifting sea water have been proofed to be possible. Checkout this.
http://www.seawatergreenhouse.com/the_process.htm

Here's a couple of diagrams of our basic design, for ease of viewing we've only included one 'circular tube' and kept their diameters the same.

Kind regards Blaine


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/05/2008 07:50:31
As you are generating a small amount of electricity it could be used to open and close valves to regulate pressure, prevent the column of water from collapsing while cavitations are refilled and to divert flow into cavitations.

If we stretched a closed loop of tubing capable of withstanding the pressures without collapse or ballooning to the top of the tallest tree, filled it with water and injected 1 mil of coloured salt solution at the top of the closed loop, we would see a complete rotation of the water inside the tube, now if we had one open ended tube the same height and joined at the bottom to the circuit and injected say 10 mils of coloured salt solution at the top of the loop that has been opened to the atmosphere via the added tube we would not only see rotation of water but we should see that water exudes from the top of the opened end allowing water to pass to the evaporation chamber. Making use of the return flow in the upward rotating flow on the juxtapose side of the complete loop to draw water back in could be achieved by using an outer tube to represent the bark of the tree and filling this tube with water. Having a sleeve of water around the tubes will provide a means to repair and prevent cavitations.

I have already shown that you can use a much smaller pipe as a down flow, even two pipes returning flow and one pipe flowing down.

Thank you for recognising my work :)

Where are you based?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/05/2008 10:44:37
Your diagram could also represent a human cerebro spinal fluid circuit. Which is where my research got really exciting for me.

Theere is going to be a bulging effect at the bottom membrane when the salts are released to flow down inducing a positive pressure, and i'm not sure that having a clean water bath at the bottom will not cause a dialysis effect from the membrane polluting the clean water?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/05/2008 20:02:20

MessageID: 172310
Today at 18:52:46 »       

If we take some tea leaves and boil them then squeeze the solutes out we can see that salts and sugars are stored in the leaves. However, gravity will always make sure that denser solutes are kept on the move so there is a constant flushing out of these salts and sugars as they are moved to sink areas, like fruits and seeds and stored as timber as tubes become redundant and more are manufactured.

Deciduous trees during the fall when the leaves are shed move solutes to the roots and higher than normal concentrations are located in the roots in autumn.

I am convinced that when the leaves fall the pressure changes in the sap to positive and forces the salts and sugars down to the roots. I have also postulated that leeching from the roots during the fall may serve as a detox ready for the spring. And this positive pressure would surely apply to the increased root growth during the fall. Let’s not forget that minerals are shed with the leaves also. During the fall the salts would remain very sluggish as transport is arrested. During the spring the warmer climate begins to change the density of the sap enabling it to circulate before the leaves are formed.

Fruits and seeds being shed also serve to remove concentrated sugars and minerals and could be considered as providing a renal function.

There is also evidence of concentrations of heavy metals around the roots of plants growing in salt marsh. Could this be evidence for leeching from the roots in addition to leeching from the soils to the roots? Could the regular influx of  brackish water in estuaries stimulate dialysis effect at the semi-permeable membrane in the roots?

Hope it's ok to copy your question to this thread as the answers are pertinent to my theory? If you object let me know and I will remove them.

Quote from: YourUncleBob on Today at 03:59:45
Unfortunately trees are not selective enough as they are killed quite quickly with an introduction of heavy metals to their water supply, or for that matter an abundance of salt!
The questions still remain. After evaporation the trees are left with a heavy concentration of salts and minerals at their tops. Are all these minerals absorbed and considered as nutritious for a tree? or Does a tree have a kind of limbic/kidney/liver system that stores any unused solutes?
or
Does a tree send the unused solutes back down to the roots?
And another question.
If a tree hates air getting into its plumbing, how do the leaves manage to let the relatively large H2O molecules out while keeping the smaller oxygen molecules from entering?
Any help on these questions would be most appreciated!

Blaine


Lmnol. Ocmno~r 43(2), 1998. 245-252
0 1998. by the American Society of Limnology and Oceanography. Inc.
Metal-rich concretions on the roots of salt marsh plants:
Mechanism and rate of formation
Bjorn Sundby
INRS-Octanologie, University du Qubec, Rimouski, QC G5L 3Al
Carlos Vale
IPIMAR, Avenida Brasilia, 1400 Lisboa, Portugal
Zsabel CaCador and Fernando Catarino
Departemento de Biologia Vegetal, Universidade de Lisboa, Campo Grande C2, Lisboa, Portugal
Maria-JoLio Madureira and Miguel Caetano
IPIMAR
Abstract
The roots of the vascular plant Spartina maritima, growing in the saltmarshes of the Tagus Estuary, Portugal,
are surrounded by tubular concretions whose diameter can reach >0.2 cm. Concretions are also found scattered
within the sediment matrix in and below the root zone. The concretions comprise 4% (DW) of the sediment and
contain 11.7 2 1.6% iron compared to 4.9 -C 0.3% iron in the sediment in which they are found. They are formed
by the precipitation of iron oxides in the pores between the sediment grains; this has filled about one-sixth of the
originally available pore space. To produce the concretions, the plants have extracted 0.25% Fe from the anoxic
bulk sediment and concentrated it into the oxidized microenvironment surrounding each root. A mass-balance model
using cylindrical geometry shows that the observed concretion density can be produced by a network of roots with
l-cm spacing. The space between the roots limits the amount of Fe that is available to a given root and thus
determines the size of the individual concretion. Field observations and mathematical modeling show that plants
can produce concretions on their roots in the space of a few weeks. The rhizoconcretions are 5-10 times enriched
in Cd, Cu, Pb, and Zn with respect to the sediment surrounding them, and the smaller diameter concretions are
more enriched than the larger ones. The preferential enrichment of the smaller diameter concretions, which was not
observed for Fe and Mn, is independent of depth in the sediment for Cd and Cu; however, for Zn and Pb, the
preferential enrichment is most pronounced within the upper trace metal-contaminated sediment layer. The rhizoconcretions
have acquired their load of metals via diffusion from the surrounding sediment. In the case of Fe and
Mn, the concentration gradient that drives the diffusion is maintained by the precipitation of insoluble oxides. In
the case of Cd, Cu, Zn, and Pb, the mechanism that maintains a concentration gradient toward the surface of the
root is not know, but our data show that S. maritima is capable of mobilizing trace metals dispersed in reducing
anoxic estuarine sediment and concentrating them into the distinct oxidized microenvironments that surround the
roots.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bass on 09/05/2008 00:50:05
Andrew
We have been doing geochemistry surveys using needles from alpine fir with some good success.  After several orientation surveys, it was determined that new growth in the early summer best concentrates the minerals.  We collect around 500 ml (1/2 quart) of needles per site.  Analyze for Sb, Ag, Pb, Zn, Cu and As- searching for antimony-silver veins and gold-arsenic veins in an area of almost impenetrable undergrowth.  Seems to work very well for known veins and have found some anomalous areas that bear further investigation.
With your discussion, should we also be looking at roots during other times of year as potential mineral collectors- or do you think that collecting soils in the vicinity of the trunks might work as well (if your process enriches the area around the trunk in heavy metals)?  Any thoughts?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 09/05/2008 14:11:05
Bass, thats a great idea :) The roots would contain these minerals in higher concentrations during the fall in deciduous trees, colloids containing metals should also be found in higher concentrations in the soil close to the roots, as trees will inevitably find trace netals and minerals with their long reaching roots and should therefore give a reliable indication of what lies in the ground beneath them. Needles on the other hand would be less rich in metals as they move due to gravity down the tree once concentrated and become locked away in the trunks and branches rather than stagnating in the needles, so taking samples close to the roots might be more accurate than collecting needles and you may have missed some important deposits. Scraping the outer part of the root for analysis should provide some interesting data, and you don't have to go to the lowest roots in order to do this because we should be looking for concentrations that have gone around the trees circuit and been excreted into the soil. Deciduous might prove better than pine as the fall changes the location of solutes due to the circulation being arrested.

http://www.lbl.gov/Science-Articles/Research-Review/Magazine/1999/stories/story3a.shtml
"We located a region of the live fungus only 400 by 400 microns in area (a micron is a millionth of a meter) where fluorescence revealed the presence of zinc," says Lamble. Graphs of x-ray absorption at electron orbitals, such as an atom's innermost K orbital, show steep rises called edges; edge shapes and positions are specific to individual elements and molecular bonds. "When we scanned the beam over the zinc K edge, we could see that the zinc was concentrated in regions only a few microns across. The shape of the K edge in the fungus sample matches the very distinctive standard graph for zinc oxalate."

 
Geraldine Lamble, an x-ray spectroscopist at the ALS.

 
 
Because the fungus stabilizes zinc in oxalate, which is indissoluble, the ectomycorrhiza can form a hard shell that keeps zinc away from the roots. "The fungus story has a happy ending," Lamble says. "Without human interference, ectomycorrhizae bind metal and stop it from leaching lower in the forest soil."

At a hundred thousand root tips per square meter, ectomycorrhizae make an effective sponge for toxic compounds. But, says Lamble, "you wouldn't want to be digging that stuff up."

Let me know what you find Bass. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: YourUncleBob on 10/05/2008 03:26:47
Andrew

I'm based in Taiwan, and I'm presently snowed under with Mid Term exam papers to mark!

We really should try to get the advocates of osmosis, 'being the primary force for the transport of water in trees', to explain away the accumulation of heavy solutes at the tops of trees.

You seem to be providing them with a way to discount the 'down' flow in the phloem pipes as the driving force by suggesting that it is the fruits, nuts and seeds that provide the 'sink' for the solutes.

How do the leaves prevent oxygen entering the tree's plumbing while letting the larger H2O molecules out?

kind regards
Blaine

PS You can do what you wish with my quotes, but I've decided not to hijack your thread with our artificial Tree (I did so because at the time it seemed to be very quiet here) and will keep my thoughts on that on the 'creating electricity from global warming thread' Which I now might have to make more mathematically formal to keep the curious fluid dynamic experts on board!

Keep up the good fight!


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2008 09:16:50
Blaine
The ever expanding roots are obviously the main sink, but we cannot deny that there is an accumulation of sugars and minerals deposited in the fruits and seeds, which fall or are eaten from the tree providing an exit point. Furthermore an apple for example acts as a kidney and bladder as solutes are flowing through it. Picture a T junction representing the flow through the branch as the horizontal part of the T and the solutes being denser flow down into the fruit causing less dense fluid to flow out of the fruit back into the horizontal flow along the branch leaving behind the sugars and minerals to ripen and sweeten the fruit.

The leaves do not prevent oxygen from entering during gas exchange to the atmosphere. It is the positive pressure and increased head of water shown in the short video on Youtube that provides the leaf with the ability to exude water from the leaf.

Picture a U tube of water filled with sap. Alter the density on the xylem side at the top and the water level in the less dense side exudes out of the other side. In the active part of the tree, instead of a U tube we have a multiple conduit system with each tubes contents affecting other tubes contents. For example, cavitations form in a xylem affecting the tension and negative pressure temporarily shutting down the circulation within changing the pressure to predominantly positive causing a reversal of the flow which inevitably changes the tension in juxtapose xylem and phloem. The gas bubbles now  are compressed and more dilute sap is pulled into the cavitated  xylem to replace the sap that was pushed out as cavities formed bringing the tube back into service as an active predominantly upwards transport to the leaves. It’s a bit like playing an organ except instead of having fingers to operate the valves we have pressure changes and density changes to regulate the flow. So to inspect a leaf to find the mechanism for selective diffusion will never provide anyone with the answers, after all it is just a leaf.

Quote
Quote from: YourUncleBob on Today at 03:03:06
Thanks Andrew,

I'm siding with you with regards to what happens to all the heavy minerals at the tops of the trees. I know that you're not a fan of the theory that says it's osmosis that provides the main power for lifting water to the tops of the trees, but to give your ideas more solidity we need to let the advocates of osmosis explain away the accumulation of these solutes at the tops of trees!

Any ideas on how the leaves prevent oxygen entering the tree's plumbing while letting out the larger water molecules?



I am not a fan of the current cohesion tension theory either, Trees are subject to the same problem that Galileo had with the 24 metre limit for drawing water up by suction. To say that water molecules evaporate and this causes the next water molecule to replace it is absurd. It’s a way of clouding the fact that we are still saying trees suck water from their roots and spit it out at the leaves. You cannot apply suction to the top of a tube and draw water up over the 24 metre limit, whether it is in an artificial tube or inside a living or dead tree. We cannot bend the rules to suit a paper. The paper must always bend to wither fit the existing rules or re-write the rules that fit with all of the other papers.

To give us some idea of the problems the literature faces we need to look at this brilliant simple experiment involving a vertical suspended vine. Note the boiling effect. I have also observed this inside my many experiments at Brixham.

The flow rates observed in trees during active transpiration is impressive and always has needed an explanation that addresses observed bulk flow rates.

·   The rattan vine may climb as high as 150 ft on the trees of the tropical rain forest in northeastern Australia to get its foliage into the sun. When the base of a vine is severed while immersed in a basin of water, water continues to be taken up. A vine less than 1 inch in diameter will "drink" water indefinitely at a rate of up to 12 ml/minute.
If forced to take water from a sealed container, the vine does so without any decrease in rate, even though the resulting vacuum becomes so great that the remaining water begins to boil spontaneously. (The boiling temperature of water decreases as the air pressure over the water decreases, which is why it takes longer to boil an egg in Denver than in New Orleans.)
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/X/Xylem.html
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/05/2008 11:44:00
Pressure Flow Hypothesis
From Wikipedia, the free encyclopedia
 
The Pressure Flow Hypothesis is the best-supported theory to explain the movement of food through the phloem.[1] It was proposed by Ernst Münch, a German plant physiologist in 1930.[2] A high concentration of organic substance inside cells of the phloem at a source, such as a leaf, creates a diffusion gradient that draws water into the cells. Movement occurs by bulk flow; phloem sap moves from sugar sources to sugar sinks by means of turgor pressure. A sugar source is any part of the plant that is producing or releasing sugar. During the plant's growth period, usually during the spring, storage organs such as the roots are sugar sources, and the plant's many growing areas are sugar sinks. The movement in phloem is bidirectional, whereas, in xylem cells, it is unidirectional (upward).

After the growth period, when the meristems are dormant, the leaves are sources, and storage organs are sinks. Developing seed-bearing organs (such as fruit) are always sinks. Because of this multi-directional flow, coupled with the fact that sap cannot move with ease between adjacent sieve-tubes, it is not unusual for sap in adjacent sieve-tubes to be flowing in opposite directions.

While movement of water and minerals through the xylem is driven by negative pressures (tension) most of the time, movement through the phloem is driven by positive hydrostatic pressures. This process is termed translocation, and is accomplished by a process called phloem loading and unloading. Cells in a sugar source "load" a sieve-tube element by actively transporting solute molecules into it. This causes water to move into the sieve-tube element by osmosis, creating pressure that pushes the sap down the tube. In sugar sinks, cells actively transport solutes out of the sieve-tube elements, producing the exactly opposite effect.

Some plants however appear not to load phloem by active transport. In these cases a mechanism known as the polymer trap mechanism was proposed by Robert Turgeon[3]. In this case small sugars such as sucrose move into intermediary cells through narrow plasmodesmata, where they are polymerised to raffinose and other larger oligosaccharides. Now they are unable to move back, but can proceed through wider plasmodesmata into the sieve tube element.

The symplastic phloem loading is confined mostly to plants in tropical rain forests and is seen as more primitive. The actively-transported apoplastic phloem loading is viewed as more advanced, as it is found in the later-evolved plants, and particularly in those in temperate and arid conditions. This mechanism may therefore have allowed plants to colonise the cooler locations.

Organic molecules such as sugars, amino acids, certain hormones, and even messenger RNAs are transported in the phloem through sieve tube elements.





[edit] References
^ Translocation of Food
^ Münch, E (1930). "Die Stoffbewegunen in der Pflanze". Verlag von Gustav Fischer, Jena: 234. 
^ Turgeon, R (1991). "Symplastic phloem loading and the sink-source transition in leaves: a model". VL Bonnemain, S Delrot, J Dainty, WJ Lucas, (eds) Recent Advances Phloem Transport and Assimilate Compartmentation. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: YourUncleBob on 12/05/2008 14:22:01
Andrew big thanks for your useful links,

However looking carefully at the inner structure of the leaf it seems the gases are exchanged in the fleshy middle and are kept away from the incoming water/solute loaded veins.

Still busy here will get back at this next week.

in the meantime Something to consider when worrying about preventing cavitations

http://www.lsbu.ac.uk/water/explan5.html#foam


Some salts prevent the coalescence of small bubbles.
Higher concentrations (often about 0.1M) of many, but not all, salts prevent the coalescence of small gas bubbles (recently reviewed [672]) in contrast to the expectation from the raised surface tension and reduced surface charge double layer effects (DLVO theory). Higher critical concentrations are required for smaller bubble size [599]. This is the reason behind the foam that is found on the seas (salt water) but not on lakes (fresh water). The salts do not directly follow the Hofmeister effects with both the anion and cation being important with one preferentially closer to the interface than the other; for example, excess hydrogen ions [1205] tend to negate the effect of halides [622]. The explanation for this unexpected phenomenon is that bubble coalescence entails a reduction in the net gas-liquid surface, which acts as a sufficiently more favorable environment for the one out of a pair of ions rather than the bulk when their concentration is higher than a critical value. It has been proposed that anions and cations may be divided into two groups α and β with α cations (Na+, K+, Mg2+) and β anions (ClO4-, CH3CO2-, SCN-) ) avoiding the surface and α anions (OH-, Cl-, SO42-) and β cations (H+, (CH3)4N+) attracted to the interface; αα and ββ anion-cation pairs then cause inhibition of bubble coalescence whereas αβ and βα pairs do not [1305]. These groupings do not behave as bulk-phase ionic kosmotropes and chaotropes, which indicates the different properties of bulk water to that at the gas-liquid surface. It is likely that the ions reside in the interfacial region, between the exterior surface layer and interior bulk water molecules, where the hydrogen bonding is naturally most disrupted [605]. A similar phenomenon is the bubble (cavity) attachment to microscopic salt particles used in microflotation, where chaotropic anions encourage bubble formation [758].
 

Interestingly, the concentration of salt in our bodies corresponds to the minimum required for optimal prevention of bubble coalescence [622]. As small bubbles are much less harmful than large bubbles, this fact is very useful.

the references can be found at the above web site.

The last little bit I highlighted, maybe of particular interest to you as you seem to have thought a lot about homosapien flows!

kind Regards Blaine
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 12/05/2008 19:16:35
Reducing the pressure at the leaf would undoubtedly assist gas exchange. tension = reduced pressure = efficient gas exchange

Andrew big thanks for your useful links,

However looking carefully at the inner structure of the leaf it seems the gases are exchanged in the fleshy middle and are kept away from the incoming water/solute loaded veins.

kind Regards Blaine

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/07/2008 21:03:53
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Concretions found walking along the river dart Estuary at low tide. The dead tree trunk and roots were above the high tide water level and surrounded by living trees that did not exhibit these mineral deposits. I suspect the high level of salt and minerals deposited on the roots eventually killed the tree.

Very similar to lime scale deposits found on urinals probably having more in common with solutes excreted from urine. In an estuary the salinity of water varies from sea water to brackish water depending upon the flow of the river water mixing with either incoming salt water from the sea or outgoing less salty water as the tide turns. The trees ability to draw this water into it’s system presents the tree with a toxic overload. In the case of the kidneys, filtration from the blood increases the density of minerals in the urine, which builds up over time on urinals that are inadequately cleaned forming very similar concretions to those pictured on this tree.
A question that arises from this observation is why are the living trees not affected by the same concretions as the one that died. Clearly this cannot be a sedimentary deposit coating the tree from the outside but must be a concretion that is excreted from the root and trunk, otherwise other trees on the same bank around the same age would also exhibit the same characteristics as those pictured.

This is a reply to Blaine's post about http://www.thenakedscientists.com/forum/index.php?topic=14146.0

Andrew K Fletcher
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 14/07/2008 22:56:15
Quote
Reducing the pressure at the leaf would undoubtedly assist gas exchange. tension = reduced pressure = efficient gas exchange
What, still peddling this 'tension' idea? Where does it come from? Why doesn't it apply all the time?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 19/07/2008 22:20:42
Pay attention to the varicose vein study and learn how solutes change pressures and apply tension to liquids. Cohesion Tension Theory mean anything to you?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 19/07/2008 23:34:46
That's surface tension - not internal tension. It's a feature of the asymmetry of forces at an interface - as you know, it is a very small force.
If it exists, it is amazing that it hasn't been used in some useful machine.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 20/07/2008 14:39:48
Just a thought re the trees a few potst up. If only the dead trees roots are covered in mineral deposits could it be that the causation runs the other way. It's not the minerals that killed the rtree, but the deadness of the tree that caused the mineralisation. For example, could bacteria feeding on the dead tree's roots have excreted something that precipitated the minerals?
For example, CO2 might be a potential reason for the mineralisation.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 20/07/2008 18:00:05
Good point BC there is a possibility that the death of the tree caused the concretions. The remaining trunk and roots were coated in the same mineral deposits. I suspect not as a bacterial process, although this also could be worth investigating, but as a result of gravity and decay causing the migration of solutes back towards the roots. We discussed this possibility in another thread relating to fossilized tree trunks found in deserts and volcanic locations where the trunk has turned to stone. Polished these reveal the ring structure of the tree and are used for ornamental and scientific interests.

This is what drew my attention to this particular trunk while walking along the estuary in Dartmouth. It may also have been a combination of the trees equivalent blocked arteries and the resulting decay that caused the solutes to exude from the trunk and form the concretions.

Either way, Gravity plays an important roll in both the trees survival and it’s inevitable death.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 20/07/2008 18:03:41
A 4 metre loop of soft walled latex or silicon tubing filled with clean water, add a little salt solution and close the loop using a union. Invert the tube and the salt flows down one side causing it to bulge visibly, while the opposite side of the vertically suspended loop is pulled in. As for a useful machine using it, it may interest you to know that our own organic machine we call the body uses it to great effect. So does another organic machine called a tree. And then there’s the massive machine called the Atlantic Conveyor system that drives the ocean currents, regulates the temperatures and powers the worlds weather, and is believed to have caused the last ice age and many others.
That's surface tension - not internal tension. It's a feature of the asymmetry of forces at an interface - as you know, it is a very small force.
If it exists, it is amazing that it hasn't been used in some useful machine.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 21/07/2008 12:17:16
We've been here before but all of those examples work under positive pressure and their operation is totally explicable in terms of pressure differences.
I would love it if you could explain to us how a single molecule, which knows nothing about its surroundings apart from its nearest neighbours, would know whether it was in a loop of tube or just an inverted tube? Why should it behave differently?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 21/07/2008 19:31:50
If they work under positive pressure then how the hell does a tube get pulled in? Stop thinking of water as water, start thinking of it as a solid. When the solutes flow down one side they apply tension to all of the molecules in the upward flowing side and a compressive force to the water molecules in front of the falling solutes. The tension generated causes the return flow tube to neck indicating that the molecules are pulling on the inside of the tubular wall while at the same time they in turn are being dragged upwards.

If the water was in the ocean rather than in a closed loop of tubing then the water molecules would still pull on all of the other molecules and initiate circulation and as there are no walls to pull on we do not see the same effects, yet the same affects apply and can be shown in tidal changes dragging water from one side of the planet to the other as the moon interacts with the earth's gravity. Same applies when pouring fuel into a car from a funnelled can. First the fluid flows slowly then it speeds up as the fuel flowing into the tank drags more fuel out of the can.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/10/2008 09:44:40
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59218

The current controversy about the “cohesion-tension” of water ascent in plants arises from the recent cryo-scanning electron microscopy (cryo-SEM) observations of xylem vessels content by Canny and coworkers (1995). On the basis of these observations it has been claimed that vessels were emptying and refilling during active transpiration in direct contradiction to the previous theory. In this study we compared the cryo-SEM data with the standard hydraulic approach on walnut (Juglans regia) petioles. The results of the two techniques were in clear conflict and could not both be right. Cryo-SEM observations of walnut petioles frozen intact on the tree in a bath of liquid nitrogen (LN2) suggested that vessel cavitation was occurring and reversing itself on a diurnal basis. Up to 30% of the vessels were embolized at midday. In contrast, the percentage of loss of hydraulic conductance (PLC) of excised petiole segments remained close to 0% throughout the day. To find out which technique was erroneous we first analyzed the possibility that PLC values were rapidly returned to zero when the xylem pressures were released. We used the centrifugal force to measure the xylem conductance of petiole segments exposed to very negative pressures and established the relevance of this technique. We then analyzed the possibility that vessels were becoming partially air-filled when exposed to LN2. Cryo-SEM observations of petiole segments frozen shortly after their xylem pressure was returned to atmospheric values agreed entirely with the PLC values. We confirmed, with water-filled capillary tubes exposed to a large centrifugal force, that it was not possible to freeze intact their content with LN2. We concluded that partially air-filled conduits were artifacts of the cryo-SEM technique in our study. We believe that the cryo-SEM observations published recently should probably be reconsidered in the light of our results before they may be used as arguments against the cohesion-tension theory.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 26/10/2008 14:38:37
Fascinating, but I'd sooner see you answer Sophie's question.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 26/10/2008 22:42:02
I think it would be water from a stone.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/10/2008 10:09:11
There are many stones that one can extract water from.

Albert Einstein
Most teachers waste their time by asking questions which are intended to discover what a pupil does not know, whereas the true art of questioning has for its purpose to discover what the pupil knows or is capable of knowing.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 27/10/2008 10:39:13
And what does this pupil know?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 27/10/2008 12:41:59
On the siphon thread. I provided you with an introduction to the spinning Z tube, designed to test the cohesion in water. There were measurements there. This is what Hammel referred to in his letter to me. You dispute the necessity for a U tube adding that a single capped tube would enable the water to remain in the tube over the 10 meter mark. I provided you with a very early attempt to do this. This was rejected because you said the pipe used was lead. Presumably then we need to alter Galileo’s Limit to using lead pipes only?

Now, why do you suppose that spinning a Z tube was preferred? Why not spin a capped ended tube? Why not spin a straight length of tube?
Both elbows in the Z tube provide the same stress on water as my experiment.

Your meniscus does not represent the strength of adhesion any more than it represents the strength of cohesion, it tells us nothing except that gravity is pulling the water down and some of the water sticks to the inside of a vessel.

Adhesion is very important for your single capped / domed ended vertical water filled pipe to work, and yes I understand why you would require adhesion to be stronger in this case. But the fact remains that no one to date has observed this. If we look around in nature for examples, do we see upright capped tubes or do we see circulation involving a flow and return system? Circulation being circular. In the body we see arterial flow and a return venous flow. In the tree we see phloem and xylem flow. In the ocean we see the conveyor system etc etc. Chop a carrot in half and we see circular patterns. We do not see a tree open at the top and bottom that is able to pull water from the soil like a giant straw and here lies the problem with science having a go at explaining circulation in a mono-directional paper, when in reality the fluids in the tree circulate.

I have seen trees 30 metres high, mostly larch with very few leaves and branches at the top, living by drawing water from root to soil.  I can photograph these if required because they destroy the cohesion tension theory, yet according to the circulation theory, little in the way of evaporation would be required for it to continue and more to the point the required tension on the sap for the current cohesion tension to work has never been observed. Despite many attempts.


Summary
The Cohesion Theory considers plant xylem as a 'vulnerable pipeline' isolated from the osmotically connected tissue cells, phloem and mycorrhizas living in symbiosis with plant roots. It is believed that water is pulled exclusively by transpiration-induced negative pressure gradients of several megapascals through continuous water columns from the roots to the foliage. Water under such negative pressures is extremely unstable, particularly given the hydrophobicity of the inner xylem walls and sap composition (lipids, proteins, mucopolysaccharides, etc.) that prevents the development of stable negative pressures larger than about −1 MPa. However, many plant physiologists still view the Cohesion Theory as the absolute and universal truth because clever wording from the proponents of this theory has concealed the recent breakdown of the Scholander pressure bomb (and other indirect methods) as qualified tools for measuring negative pressures in transpiring plants. Here we show that the arguments of the proponents of the Cohesion Theory are completely misleading. We further present an enormous bulk of evidence supporting the view that – depending on the species and ecophysiological context – many other forces, additional to low tensions, can be involved in water ascent and that water can be lifted by a series of watergates (like ships in staircase locks).
 
Received: 16 October 2003 Accepted: 30 January 2004


http://www3.interscience.wiley.com/journal/118760238/abstract?CRETRY=1&SRETRY=0

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 27/10/2008 14:42:28
There is no point in discussing the siphon phenomenon any more because your appreciation of it is incomplete and you don't seem to want to advance your knowledge at all in that direction.
Yes, trees are wonderful. Yes, there have been experiments on cohesion. But your explanation is what lacks rigour and depth.
I have no quarrel with your external references because they talk sense and do not neglect the effects of adhesion.  I can only conclude that you don't understand all they say.
I can't take you seriously if you can't even discuss the water meniscus in normal terms. Is that piece of theory all wrong as well?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 27/10/2008 18:57:46
Fascinating Andrew,
but I'd sooner see you answer Sophie's question
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 09:06:34
lacking rigour and depth as you put it could also equate to keeping it simple. Investigating how this flow and return system fits with human, animal, tree and plant physiology has been trully fascinating. Observing a recovery from cerebral palsy where a girl gets out of a wheelchair and climbs stairs in school after 12 years of being unable to walk: Priceless
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 11:08:20
Lacking rigour may be fun but the results of that approach are just not reliable. Furthermore, without some rigour in Medical tests, you cannot be sure that what you did was the reason for the observed effect.
Do you choose to go to a modern Doctor or be treated by one who follows Galen's (simple) methods and beliefs?

"Keeping it simple" can lose the whole point of something. A child believes in the Tooth Fairy because that model fits a limited set of observations. When you tell a child "Of course she came for your tooth - see - she left you some money", is that really a Proof?. Children grow out of that simple belief.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 14:24:50
You may want to believe that a spontaneous remission from brain damage at birth was a coincidence following a phone call from a parent who was enquiring about a bull terrier and asking my opinion about the breed and how an adult male would be around a severely disabled child. That day this mum got more than she anticipated and agreed to test IBT with her child to see if anything would happen.

Given than nothing had happened in 12 years previous regarding recovery it was indeed a long shot, but a shot well worth taking.
I received a call out of the blue one-day. It was a little girl called Caroline, who rang to ask if I was Andrew, the man who told her mum to tilt the bed. I replied yes, is this Caroline. She replied. I am calling to say thank you for all that you have done for me.

My legs went to jelly that day. Tears were falling from my chin and I collapsed on the floor unable to stand while the little girl told me about how much her life had changed for the better. Not only could she now walk, but the muscles in her legs were restored, her legs were straight, scoliosis had been reversed, she can clothe herself and brush her own hair, something a top neurologist in Wales said could never happen.

It is entirely your prerogative to choose to ignore what I have written here because to-date no controlled study has reproduced the results. Another girl around the same age also began to respond following an article in the Daily Mail National Newspaper relating to recoveries from multiple sclerosis.   
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Remember. I have never asked anyone for a single penny for helping them to recover. In fact my research has cost me many thousands of pounds over the years. What possible motive other than truth could I have for pursuing this important discovery?

If this was your own daughter, would you still require evidence that the bed has been rigorously tested? After all, the parents only had my word that there was a chance this could help their daughter.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 28/10/2008 14:37:57
Andrew, people aren't disputing that you have seen results - it's the descriptions of the mechanisms that they dispute.  These threads are pretty hard to read, as you're a bit like a politician - evading answering the actual questions.  This latest post is just more of the same...
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 28/10/2008 15:05:03
Just because you're sincere (and I don't think anyone doubts that) doesn't mean you're right.

And given that I can explain all the results of your siphon experiments I've seen to date in terms of conventional current physics, your explanation for the mechanism by which IBT achieves its observd effects is getting in the way of the application of what could be an important discovery by making it really hard for the rest of the world to take you seriously.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 16:50:55
I really can't see how a perceived medical success 'proves' anything about the explanation of how tension in water works. One is a recorded event and the other is a quaint personal notion. Where is the proof of any causal connection?
I believe you are upset by the wrong issue here. If something you have done has helped someones medical condition that is a wonderful thing. But does it make your understanding of Science correct?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 17:25:16
Ben, can you ask me a question that I have evaded?

Rosy, A siphon does not work above 32 feet limit. You agreed in this thread that this was not a siphon, so what has changed since then? This is an age old problem that goes back to before Galileo.

Whether anyone believes the theory or not is irrelevant for people who need help. The question is why has IBT not been reproduced by doctors, surgeons and nurses? For god’s sake, it’s a couple of blocks of wood under a bed that is producing the results. It is nothing short of criminal for this not to have been investigated!

Hiding behind any excuse that prevents tilting a bed in a hospital when circulation is compromised, renal failure has begun and oedema is evident and nothing in the allopathic arsenal is working for the person in the flat bed, does it not reflect very badly on not only the staff and hospital but on the very health care that is supposed to be providing these fragile people with support. I have fought at my own Father’s bedside, have shown the results to the staff and doctors at Russell’s Hall Hospital by bringing him from a comatose state with supposedly irreversible multiple organ failure, while he was fighting cancer to watching his kidneys start functioning and clear urine instead of brown bloody tar in the Catheter bag. His blood pressure returned to normal and his massive swollen legs were observed to shrink before the doctors eyes, buying him and my family a precious 8 months further. Yet every time I went away from the hospital, His bed was deliberately placed flat. Even when the staff had witnessed the huge improvements, they took it upon themselves to ignore the obvious results and place his life in jeopardy once again.

When my Father finally ended up back at the same hospital after collapsing once more, he was again subjected to the same ignorance which caused him to become comatose every time his bed was put flat, and every time it was tilted after a running battle he was observed to gain consciousness. The damage that the drugs he was given for diabetes (which he never had) -Metformin, together with the incompetence of the staff at Russell’s Hall Hospital made certain my Father stood little to no chance of fighting his illness. Infection followed and he eventually lost his life without so much as a single paracetamol to relieve his suffering from cancer of the gall bladder and liver. He refused to take any more medication from doctors right to the end.

So when people give me a hard time for failing to put this together in a way that is acceptable to them, spare a thought to the simplicity of the intervention and ask yourselves why has nothing been done to make sure this important discovery is not washed under the carpet for another 10 years or more.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 28/10/2008 17:53:21
The main question you have been evading recently is why should a molecule in an inverted u-tube act any differently to one in a single, dome capped tube, or words to that effect, from Sophie.

Andrew, no one here is doing anything to halt research into this, and no-one has any vested interest in seeing you fail.  I'm with Rosy on this one, we know you're sincere, and I don't doubt that inclining your bed has some great effects, but I'm not convinced by your proposed mechanism, and I think that's the issue.  The main thing for me is that your models seem to ignore certain key things - the massive pump involved in the human circulation system, which would make any other effect minor, and the many pores at the top of a tree.  Have you re-created your experiment allowing water to evaporate from the top (which we know does happen in trees from direct observation)?  Have you re-created the human circulation experiment with a great big pump in it?

The amount of anecdotal evidence you have certainly suggests that it is worth studying the effect of an inclined bed, and I wish you all the best with it/  However I, like Rosy, suspect that by pushing your hypothesis as well as the results you've achieved, you make it harder for people to take you seriously.

(and as a small co-incidence, I used to drive past Russel's Hall quite often)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 28/10/2008 18:06:59
Fascinating Andrew,
but I'd sooner see you answer Sophie's question
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 19:55:08
I replied to Sophie that the molecules are subjected to tension due to the weight of each column of water being suspended over an inverted U tube, this is causing the water to become stretched like liquid elastic and can be tested by blowing or sucking on one side of the tube when suspended vertical over 24 metres. More to the point when the open ends of the tubes are pulled from the water the water inside the tube does not flow out unless the bead of water has cavitated. In fact the water springs up the tube on both sides to a level depending on the height of the tube. So the higher the tube is elevated the more tension is applied to the water.

Having a capped ended tube relies on adhesion too much so is destined to fail because the small area at the top of the tube cannot support the weight. Cavitation caused by the tension will inevitably form at the top of the capped tube releasing the adhesion of the water molecules at the top. The adhesion of the water on the sides of the tube only serves to stop the water from necking under the tension. We can see that adhesion is not a holding factor along the entire length of tube because once the experiment fails the water runs out.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 19:59:40

IBT is very good for Alzheimer’s too BC. I can see you are having trouble remembering your previous posts so may I recommend two blocks of wood under the head end of the bed as a remedy for your recent repetitive behaviour and short term memory loss.
Fascinating Andrew,
but I'd sooner see you answer Sophie's question

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 20:16:55
But BC's right. An answer would be good.
BenV understood what I wanted so read his post if you couldn't understand what I was asking.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 21:20:58
It seems perfectly logical to me why a U tube works and a capped tube won't work. Why do you think I tested a U tube?

Ben you mention we have a heart. In embryology circulation is evident long before the heart forms into the familiar shape. Oddly enough a U tube forms first and there is a pulsatile flow evident before the heart begins to beat. Chick egg embryo is a good place to start on this one. So we don't need a heart to circulate fluids. What we need is a driving force that begins the process of life.

Does the applied tension aggravate / excite the molecules? I don’t know Does the downward flow drag the cavitations away from the top of the U tube and assist the water to remain intact for longer than an upright tube where the vapour bubbles rise to the top and cause the adhesion to fail higher than 10 meters? Probably

As for no one doing anything to halt research. No one is doing anything to progress research into it either! Doing nothing is something I have grown to expect over the years from the very people who should be working and testing this to save lives and improve lives.

How many of you have bothered to even observe this flow and return system in the scaled down version shown on Youtube? How many have taken the time to understand it?

An adhesive attached molecule behaves differently to a molecule that sticks to another molecule. For example all of the water molecules are pulling towards each other attracting at opposite polarity. So they are in effect pulling the water away from the tube towards the greater mass of water. Is the alignment of all of the molecules playing a part in causing the single upright-capped tube to fail? I see no point in talking about Sophie’s thought experiment when Sophie is not prepared to test the thought experiment and would rather assume that the 10 meter limit has never been a limit. Either way the text books are completely wrong. So why make a fuss over such a minor problem?

·   The fact of the matter is. Billions of people have been brainwashed into believing there is no point in testing the 10 meter limit because it looked right on paper. The maths were correct. Brilliant scientists said it can’t happen. Engineers have tested it over the centuries. Fire-fighters even offer prizes for raising water over the limit.

So may I ask you all what you might think the differences are?




Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 21:39:54
"it's perfectly logical to me"
Is that supposed to be a scientific answer?

Can you be surprised that I can't take you seriously?
What do you think they would have said to Sir Isaac if he'd written that in his Principia?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 21:54:45
oh yes. The difference between your experiment and the ones described by other workers (including firemen) is that your effect is short lived; even the link you quoted refers to "dynamic" tension in water.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 22:12:44
I also stated this was an experiment to test the tension and flow, not to represent a tree. Adding if I put my tubes inside another tube to represent the bark of a tree, we could exceed the 24 metres with ease and have water evaporating from the top because the water would be supported by the outer tube. We would also still see negative pressure beeing able to cause water to be drawn in at the base and as solutes flow down wee would see an increase in head of water at the top explaining how trees are able to stack growth at an ever increasing height, something that is not addressed in your precious cohesion tension theory.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 28/10/2008 22:18:05
Its an engineers answer. Its the answer that caused water to flow up vertical to 24 metres! It's the logic that tested your 10 meter limit and destroyed it. It's the same logic that applied the flow and return system to human physiology. Tell you what. Ignore my work and discovery, and everything I write and assume I am away with the fairies why don’t you. If you can’t understand something then at least try it out and explain it better if you feel able to.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 28/10/2008 22:41:55
I don't have a cohesion tension theory. Do you read what I write?
My only problem is that you insist that there is something magically different about the two water molecules at the top of the two tubes (u and domed). You have yet to answer that straightforward question.
In both cases, unless water is a solid, it will part company with the upper surface if there is not enough adhesion.
You still refuse to discuss this issue. Why? Does a liquid not flow when a force acts on it? Your tension would pull it away from the top surface unless some balancing force were keeping it there.
Such a straightforward question. Yet you don't answer it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 09:26:07
BTW, Andrew, a competent Engineer would know how any black box he uses will work because he couldn't risk it failing to perform as he expects when tested. You have been using a black box all the time but have no idea what is going on inside. You're no Engineer. There goes another group of workers who you have denigrated.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/10/2008 10:23:47
Sophie You are forgetting one very important observation which you must consider.

The flow from one vessel to another both at ground level therefore at = pressures, yet clearly visible in the Brixham video as being far superior to the flow rates observed in trees. Adhesion as you state is responsible for sticking the water to the inside of the tube, Cohesion evident in the flow from one vessel to another is clearly not relying on adhesion. Once the bead of water is severed by cavitations the water flows from the tube ends and empties it if they are removed from the water at ground level. Adhesion clearly is not as important for suspending the water. When the water bead collapses and the tube endings remain in the water at ground level. The water falls back to the 10 metre level. The space above it being vacuum as was shown in the original problem of the pump by Galileo and co.

Your last post appears to be stating the obvious again regarding adhesion in the tube and this is where I fear we may have had crossed lines. I was relating to your capped end tube all along. I see no point in stating the obvious. One could go on to argue that the cord used to raise the rope exerts a constricting pressure and the downward pulling on the cord over a pulley block exerts an upward motion to the tube and the air……. pressure exerts a positive pressure outside the tube and on the water in the reservoir’s at ground level. Why complicate a simple successful experiment when all this is obvious to the observer? This may be required for a patent application, but surely not for a simple tubular experiment?

Nevertheless. I melted the end of a 130 CM length of the same tubing used in the Brixham experiment, Blew down so the molten end formed a bulb as you suggested, filled it with tap water making sure no bubble were present, held it up and noted that water did not flow out of the end as expected. Applied a very moderate centrifugal force by holding the closed end and gently rotating it to find with little to no force water flowed from the end as expected.

Next: Repeated the same with previously boiled / degassed water and found that there may have been slight (if any) increase in resistance to the bead of water failing. The tube was at no point rotated the tube differently to force the bead of water to break and the tension could not have been any where close to that observed in the Brixham Experiment at 24 meters. One could argue that the air flowing passed the open end increased the tension on the water inside the tube, but trust me on this, I did the experiment to see for myself if adhesion could support the water in a 6 mil bore nylon tube, not to make it fail but to try to make it work.

Again I must state that there is little to no point repeating the same experiment with a longer length of tubing as the force exerted by the column of suspended water will easily cause the water to be pulled from the tube.

It may interest you to know that when the U tube is performed lower than 10 metres and the ends of the tubes are removed from the water, the water flows out and will not remain in the tubes. I look forward very much to your comment on this observation too.
 
Andrew K Fletcher

Albert Einstein
One had to cram all this stuff into one's mind for the examinations, whether one liked it or not. This coercion had such a deterring effect on me that, after I had passed the final examination, I found the consideration of any scientific problems distasteful to me for an entire year.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/10/2008 10:44:40
If you were a thinker instead of a sheep you would engage your brain before opening your mouth. Again you attack me. It is I that has trashed the bull that you have been teaching not you that has trashed my experiments. Worth remembering that don't you think?
Any moron can keep churning out the same written literature without questioning it.

Albert Einstein
Humiliation and mental oppression by ignorant and selfish teachers wreak havoc in the youthful mind that can never be undone and often exert a baleful influence in later life.


BTW, Andrew, a competent Engineer would know how any black box he uses will work because he couldn't risk it failing to perform as he expects when tested. You have been using a black box all the time but have no idea what is going on inside. You're no Engineer. There goes another group of workers who you have denigrated.

Albert Einstein
Education is what remains after one has forgotten everything he learned in school.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 11:34:20
I have just read your last outburst, which I will ignore.
I was about to post the following reply when I read it.You will notice that I am trying to be constructive.:

Quote
I see no point in stating the obvious
It may appear obvious to you but nothing is 'just obvious' in Science. If you have an incomplete model in your mind of what is going on then you can't explain this.
The reason that you don't explain it must be because you can't.
You are doing to me exactly what you claim that Science teaching is doing to children.
What you are saying. effectively, is "You just have to accept this obvious fact". If it isn't obvious to me then are you going to shout at me as if I were a naughty / thick child or are you going to try to help me with my obvious misconception?
Which should I do if I were trying to get an idea across to a child who didn't get what I was saying?

Some comments:
Quote
Cohesion evident in the flow from one vessel to another is clearly not relying on adhesion
Do you have a cohesion meter and an adhesion meter to tell you this? What justification for this statement? (we are not dealing with a chain or wire made up of a solid substance)

Quote
I was relating to your capped end tube all along.
But I was, 'all along', asking you to draw a distinction between the two situations - yours and mine.

Quote
One could go on to argue that the cord used to raise the rope exerts a constricting pressure

Precisely. The weight of the rope will pull down on the pulley. The rope is a solid and, despite being able to distort a little (become a bit narrower and longer), the 'constricting pressure' is balanced by the molecular forces which are there - the properties of a solid. If you were to hang a length of chewing gum (a very plastic substance) over the pulley the gum would stretch and get thinner because it would flow. Water flows, too, but more easily, so you would expect the same if you didn't provide the tube outside it which could provide some extra forces.

Quote
I melted the end of a 130 CM length of the same tubing used in the Brixham experiment
Well, you did try.  It worked as expected.  During your whirling phase, it is not surprising that water flowed out - the tube could flex and bubbles would have been admitted into the bottom, allowing air in.  Also, the opening at the bottom would not have been horizontal so there would have been a pressure differential (Hydrostatic - not atmospheric) across the inverted surface of water - that would start a water flow - you can see this happen with an inverted bottle of water, too where the water flows (gloops)  out quicker if the bottle is not exactly vertical. If you had suspended the tube motionless and tapped the sides I would expect the same sort of thing to happen. It was worthwhile trying but you were not in a position to see what was actually going on inside the tube. If you were to try the same thing with your U tube, I think the water would fly out even quicker with such rough handling (see the last comment on this post for the reason).

Quote
Again I must state that there is little to no point repeating the same experiment with a longer length of tubing as the force exerted by the column of suspended water will easily cause the water to be pulled from the tube.
That presupposes your original ideas are correct and that the inside of the top of the tube was as smooth as the top of the looped U tube.
There are many problems associated with implementing the closed tube experiment and I can see how the continuous loop provides both a much smoother surface and a better chance of eliminating bubbles. That is a practical and not a fundamental difference between the two experiments. Very easy to draw the wrong conclusions about the actual mechanisms at work.

Quote
It may interest you to know that when the U tube is performed lower than 10 metres and the ends of the tubes are removed from the water, the water flows out and will not remain in the tubes
That is precisely what I should have expected to happen. It's an unstable situation. Unless the two arms of the tube are precisely the same length then there will be a hydrostatic pressure differential across them causing water to flow. Once it has started, the difference increases further and the flow will increase.  If the tubes are kept in small reservoirs, such as in your original videos, the levels will self-adjust. This, of course, explains why, when you added a more dense liquid to one side, the levels started to change; the hydrostatic pressures are not equal. If you were to raise the side with the salt in, you would find a new position in which the flow would be zero. (Until diffusion of the salt solution into the freshwater side started to change things).

To sum up, I can see nothing in your last post which proves or justifies further you explanations. Half way through you, yet again, beg the whole question by making the assumption all over again.
All you have described fits in perfectly with conventional theory.
I think I have identified the crux of our differences  enough times. Are you really not capable of answering my one small point about the way the molecules must be working 'at the top' IN BOTH CASES?

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/10/2008 12:33:10
It was Einstein not me that wrote those quotes attacking his own experience in the education system.

To sum up:

1 the experiments at Brixham were roughly handled over a relatively prolonged period of time, due to the person at the top of the cliff lowering the tube rather than holding it steady, yet the bead of water remained intact as shown in the unedited actual time footage. More experiments have been done many times and recorded showing this bead of water to be a lot more robust than you are imagining it to be. I knew you would argue that gently rotating the smaller capped tube would not represent the longer tube. But surely you can comprehend how much tension there is in a u tube suspended to 78 feet = two columns of water pulling on each other. The tension BTW should be the same throughout the water column, because as you state each moecule must act on it's neighbouring molecules. A further experiment was conducted at a greater height than 24 metres. The water inside the tube was observed to boil without heat.






I have just read your last outburst, which I will ignore.
I was about to post the following reply when I read it.You will notice that I am trying to be constructive.:

Quote
I see no point in stating the obvious
It may appear obvious to you but nothing is 'just obvious' in Science. If you have an incomplete model in your mind of what is going on then you can't explain this.
The reason that you don't explain it must be because you can't.
You are doing to me exactly what you claim that Science teaching is doing to children.
What you are saying. effectively, is "You just have to accept this obvious fact". If it isn't obvious to me then are you going to shout at me as if I were a naughty / thick child or are you going to try to help me with my obvious misconception?
Which should I do if I were trying to get an idea across to a child who didn't get what I was saying?

Some comments:
Quote
Cohesion evident in the flow from one vessel to another is clearly not relying on adhesion
Do you have a cohesion meter and an adhesion meter to tell you this? What justification for this statement? (we are not dealing with a chain or wire made up of a solid substance)

Quote
I was relating to your capped end tube all along.
But I was, 'all along', asking you to draw a distinction between the two situations - yours and mine.

Quote
One could go on to argue that the cord used to raise the rope exerts a constricting pressure

Precisely. The weight of the rope will pull down on the pulley. The rope is a solid and, despite being able to distort a little (become a bit narrower and longer), the 'constricting pressure' is balanced by the molecular forces which are there - the properties of a solid. If you were to hang a length of chewing gum (a very plastic substance) over the pulley the gum would stretch and get thinner because it would flow. Water flows, too, but more easily, so you would expect the same if you didn't provide the tube outside it which could provide some extra forces.

Quote
I melted the end of a 130 CM length of the same tubing used in the Brixham experiment
Well, you did try.  It worked as expected.  During your whirling phase, it is not surprising that water flowed out - the tube could flex and bubbles would have been admitted into the bottom, allowing air in.  Also, the opening at the bottom would not have been horizontal so there would have been a pressure differential (Hydrostatic - not atmospheric) across the inverted surface of water - that would start a water flow - you can see this happen with an inverted bottle of water, too where the water flows (gloops)  out quicker if the bottle is not exactly vertical. If you had suspended the tube motionless and tapped the sides I would expect the same sort of thing to happen. It was worthwhile trying but you were not in a position to see what was actually going on inside the tube. If you were to try the same thing with your U tube, I think the water would fly out even quicker with such rough handling (see the last comment on this post for the reason).

Quote
Again I must state that there is little to no point repeating the same experiment with a longer length of tubing as the force exerted by the column of suspended water will easily cause the water to be pulled from the tube.
That presupposes your original ideas are correct and that the inside of the top of the tube was as smooth as the top of the looped U tube.
There are many problems associated with implementing the closed tube experiment and I can see how the continuous loop provides both a much smoother surface and a better chance of eliminating bubbles. That is a practical and not a fundamental difference between the two experiments. Very easy to draw the wrong conclusions about the actual mechanisms at work.

Quote
It may interest you to know that when the U tube is performed lower than 10 metres and the ends of the tubes are removed from the water, the water flows out and will not remain in the tubes
That is precisely what I should have expected to happen. It's an unstable situation. Unless the two arms of the tube are precisely the same length then there will be a hydrostatic pressure differential across them causing water to flow. Once it has started, the difference increases further and the flow will increase.  If the tubes are kept in small reservoirs, such as in your original videos, the levels will self-adjust. This, of course, explains why, when you added a more dense liquid to one side, the levels started to change; the hydrostatic pressures are not equal. If you were to raise the side with the salt in, you would find a new position in which the flow would be zero. (Until diffusion of the salt solution into the freshwater side started to change things).

To sum up, I can see nothing in your last post which proves or justifies further you explanations. Half way through you, yet again, beg the whole question by making the assumption all over again.
All you have described fits in perfectly with conventional theory.
I think I have identified the crux of our differences  enough times. Are you really not capable of answering my one small point about the way the molecules must be working 'at the top' IN BOTH CASES?

By the way, bubbles being admited into the bottom of the whiling tube will not alter the adhesion at the top of the tube with a mere two rotations will it? How do those bubbles travel from the opend end to the top of the capped tube while it is generating centrifugal force towards the ends of the pipe? What really happens in the tube is that the weight of the water exerts too much force on the molecules stuck to the top of your domed capped tube ending.


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: neilep on 29/10/2008 13:16:19
Glad to see everyone is being so cordial, courteous and gracious   [;)] [;D]

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 14:13:24
Thank you Neil!
Andrew:
You need to refomat your post. The quote includes some of your own words at the bottom, I think.

Your original post did not discuss how the space at the top had formed. Are you suggesting that the gap at the top of the tube was a vacuum? In which case , when you removed your 'extra force', the water would have gone back up to the top (as Galileo et al have found). If the gap remained, then it was full of air. This air can only have got there as bubbles from the bottom, out of solution or via a leak in your 'sealed end.  It must have come from somewhere.
Quote
The tension BTW should be the same throughout the water column,
Just not true. If you take a chain (of finite mass) and hang it up. The tension between the bottom two links is equal to the weight of the bottom link. The tension between the top two links is equal to the weight of the whole chain - less the top link weight.  How can the bottom link 'know' how many links there are above it? If there were more  tension acting on the bottom link than its weight then  it would move upwards. (Newton's First Law of Motion applies, as always)

How can you pontificate about this topic if you make a simple error like that? Some serious rethinking is needed, I fear.

I wouldn't mind betting that Einstein made a point of learning, thoroughly,  all about Newtonian Physics before he started leading off that it was inadequate or wrong. He never treated anything as 'obvious'.
I can sympathise with him regarding his view that his education was lacking. HE, as it proved later, was actually very clever  and was probably frustrated at his teachers not even approaching him in ability and he never did suffer from an understated ego.  Andrew - you are no Einstein.
I am just a humble proponent of a system which seems to work very well and is very consistent (except at its esoteric edges) - because the people who have constructed it are are lot more clever than you or I. But I do my best to avoid skating around difficult points - unlike you, who still refuse to address one pivotal question which I need not repeat, surely.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: JimBob on 29/10/2008 15:07:25
Y
Glad to see everyone is being so cordial, courteous and gracious   [;)] [;D]


And we could always determine the outcome of this by, oh, say broadswords. No light sabers - this is an age of enlightenment.

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.angelfire.com%2Ftheforce%2Femprs_palpatine%2Fsmilies%2Ffight1.gif&hash=8f0d5e01be12fac7e4a329c5987e5748)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 15:16:39
Keyboards at dawn, I think. Or any other time in the 24hr cycle.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 15:16:54
Can you feel the tension?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: paul.fr on 29/10/2008 15:54:37
Glad to see everyone is being so cordial, courteous and gracious   [;)] [;D]



Well im only reading this topic for the insults. Although i do find in upsetting when two grown men (ok, one may or may not be a woman..oh and i discount BC because he is a chemist) yadda yadda yadda...

Lokk, just get on with slagging eachother off, i have popcorn ready you know!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 16:07:13
All I want is an answer and all will be clear folks.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/10/2008 16:12:14
You know Sophie, you must be correct. I must be a complete idiot for showing you that water can be placed under tension when you refuted it. But where does that leave you?

Tension is brewing
Of course every molecule in the columns is under tension. Each and every single one of them. The downward pull from gravity on the water must also have an effect on the walls of the stiff nylon tubing, but not sufficient to account for the water springing up the tube when the ends are removed from the water container at ground level.

Add a pinch of salt to one side and water is drawn up under tension. Not because of pressure changes either. 1 grain of salt will trigger this flow! How can you account for this in pressure changes?  Surely this flow is responsible for generating the pressures and not the other way around. What drives the circulation before a heart forms? Gravity is a good starting place! This is not the same as a siphon. I keep trying to explain that there is a huge difference between a siphon flow and a density flow. Thought experiment. Coloured salt solution added to upward flow side of a siphon in sufficient quantity to generate a density flow in the upward flowing side. Here we have a downward density flow in the same side as an upward flowing siphon flow. Seen it done it!

Do I have a laboratory and unlimited funds to go with my cohesion and adhesion measuring device? Perhaps an entire university behind me even as you do?

You avoid most of my questions and ignore most of my answers and concentrate on what is happening to the molecules inside the tube? I do not understand what you want from me other than for me to become a verbal punch bag that is?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 29/10/2008 19:16:13
Fascinating, but I'd sooner see you answer Sophie's question.
 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/10/2008 19:31:02
I did try to deal with all the issues in your last post. Did I avoid any of them?
I am surprised that you don't think the behaviour of molecules is relevant to the way substances behave. To my mind that is a crucial issue upon which all other things in this topic must hinge. Any explanation just has to include the molecular consideration or we are back in the middle ages.

Have you given some thought to my chewing gum idea? Is that not relevant to the situation with water?

One grain of salt will cause a flow? Of course it will. The solution around it is more dense and will drop through the fresh water, albeit quite slowly. It would be a real surprise if it stayed there or went up.

What is 'surely' about the flow generating the pressure? You can measure a pressure difference with out needing any flow. As I suggested, try raising the salty side and you will get a balance point (equalise the pressure difference) with no flow. Why do you muddle up cause and effect so often? What do you suppose started the flow in the first place? Everything needs energy from somewhere to make it happen. Where does the energy come from for your flow if not from the salt having been lifted, by some means or another and gaining Gravitational Potential.

How about my question regarding the space that you saw above the column of water? Did it stay there? Was it air? How did it get there?  There is an interesting practical question here.

The fact that an open-bottomed U tube doesn't stay full is very well explained in terms of small pressure difference. You have not replied to my general comments about your latest trials. I think they were mostly good-willed comments??

What is a "density flow"? It is not a term in common use.

I fully believe you saw what you saw but the girl saw the tooth fairy's money too. Was she right to believe in the tooth fairy? She could have found the real cause by the appropriate experiment - staying awake all night- or asking someone who knows.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 31/10/2008 09:27:02
Ok let me ask you to state what you know about the Brixham experiment.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 31/10/2008 18:27:50
There's no point in going into too much detail but what it has actually 'proved', rather than what you have 'seen in it' is as follows. Water, under reduced pressure, will not boil instantly. It exhibits cohesion and adhesion. The forces of adhesion and cohesion, as a pair, sustain a siphon process when you increase the density of the liquid on one side of a U tube.
That, in itself, makes the Brixham Experiment well worthwhile having been done. It is a surprising result but reasonable with hindsight. There is, elsewhere, work which shows and measures the 'dynamic (temporary) tensile strength' of water under negative pressures.
You have not yet answered my objections /  questions regarding the results of your recent single tube experiment. They are the same questions that I would have asked myself if I had done the work myself - I was not trying to give you a hard time about it.

Your explanation and the undefined terms you use (such as density flow,  for instance) are not the only ones possible.

My explanation uses conventional and well tested ideas and tries to use as much of the existing knowledge as possible.

If you really had a convincing package of explanations for the phenomenon then you should be able to reconcile your ideas with such fundamental questions as mine regarding how the molecules behave at the top. You have still not managed to answer this in any depth. You just cannot ignore the problem or dismiss it as obvious - it isn't.

Remember - you are the one who is introducing a new idea and rejecting the established one. The burden of proof lies with you. That is, if you want it to be taken seriously.
Are you still not prepared to discuss the molecular situation and the nature of the forces all through the water?
Rather than just getting upset that your ideas haven't been accepted without argument, you need to substantiate them better.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 01/11/2008 01:52:50
I'd really like to see Andrew answer whether the column of water would remain intact if the tube were removed.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 01/11/2008 10:08:36
SophieCentaur.

Thank you for your reply

However, you have not stated anything I have not already stated other than mentioning the adhesion of water to the inside of the tube, which to me at least was obvious. In other posts, I have mentioned this, as soft walled tubes collapse when tension is applied. Again it is obvious that the water is still stuck to the tube and that the tension is pulling on those molecules which in turn pull on the tube. One could also argue that the adhesion inside the tube, coupled with the applied tension lowers the pressure inside a soft-walled tube to the point where atmospheric pressure pushes the tube in and that it does so because air molecules are in contact with the outside of the tube. I have also stated time and time again that the water resists the tendency to boil over the 10 metre mark, even adding when you take the experiment considerably higher than 24 metres the water boils as would expect it to. Even stating that adhesion in certain previous experiments was the reason for failure when cohesion in an unbroken column of water succeeds. Somewhere, I have also stated about my friend Adrian Van Sweden, a brilliant physicist, and former water engineer from South West Water sat on a step with his hands covering his face saying this is not possible after witnessing my experiments. He added water cannot exist in a negative pressure environment but here it is. Why have I not been taught this?

Remember what I said about working with a siphon over 10 metres
As you lower one vessel it stretches the water on the side that you are lowering causing cavitation and eventual failure. It does not induce a flow from one vessel to another. This is worth considering because had it ever have done so it would have been in the literature by now, as many engineers, plumbers, pipe fitters, boilermakers, fire fighters, irrigation experts, have all entertained this problem.

The spinning Z tube where water is injected at the centre of the Z causes the water to cavitate when sufficient tension has been applied. As water passes over the elbows of the Z tube rotating clockwise it induces tension that can be measured accurately.

Hindsight is an easy word to say after an event, but a difficult word to comprehend before an event.   

The 6 mil bore tubing capped and swung around gently caused the water to empty from the tube without any deliberate whipping or flexing in the tube. I wanted this experiment to succeed by the way as I have to admit there was a chance it could have, albeit slim. Even using degassed, pre-boiled water it made little to no difference. The spinning Z tube on the other hand confirms the huge tensile strength of water and as the Z tube is of a very small size, adhesion provides the stability of the injected water preventing it from necking. In a soft tube this necking is illustrated. In a solid walled tube not so obvious.

This is why IBT is important for varicose veins shrinking and oedema being drawn from the surrounding tissue back into the circulation. The density flow through the arteries induces the tension in the veins causing the fluids to pull the veins in as the pressure is relieved that causes them to bulge.

Studying trees on the other hand is more difficult due to the rigidity of the tubes, except in the stages of tube production just beneath the bark. This is where pressures and adhesion count in the liquids before they become solid tubes. The pressure in the liquid caused by the gravity induced downward flow resulting from solute free evaporation at the leaf enables a flow without tubes under a positive pressure, essential for maintaining the inside diameter of the forming tubular cells. And lignifications strengthen the walls around the flow by attracting and hanging on to the molecules of resin suspended in the sap. So here lies the answer to yours and Stefan’s valid question about whether a flow can exist without tubes. In fact circulation in all creatures begins long before any tubes are formed.   

Andrew K Fletcher
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 01/11/2008 10:52:12
Why do you bother to include comments about trees and IBT in your reply?
The fact that you can observe certain effects does not justify your explanations of one simple effect. You just cloud the issue.

You will notice a scattering of posts from other members amongst our dialogue. They all include the same basic question as mine regarding the basics of what happens at the surfaces of the tubes, in molecular terms.

I assure you that we are not all 'ganging up' on you about this. You should take it as a sign that the question really does need answering.

You keep doing exactly what you complain that teachers of Science do. You expect us to believe in something and refuse to look outside your particular model. Just consider, for a moment, that you could be wrong in this particular aspect of what you (think you) understand.

You went to the trouble of experimenting with the single tube - that's good. But why don't you reply to my queries about experimental details? I am a pretty experienced experimenter and my points are valid.

Please stop repeating your anecdotes and answer the main question. I will then stop asking it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 01/11/2008 18:33:06
If you have something to add about molecular behaviour in tubes then spit it out man. You appear not to be asking a question but to be implying you know the answer to your own question so get on with it.

I mentioned the tubular growth in trees because I was asked how this flow system could be there without tubes. The reference to soft walled tubes was required to explain how a flow could cause tubes to form with the flow maintained inside them once they have formed.

Perhaps you would like to explain why water inside the tube does not conform to the phase diagram of water to people viewing this thread too?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 01/11/2008 21:44:53
I'll spit it out, 'man'.

If the water is to stay in contact with the top of your U tube or my single tube, the molecules at the very top must be attracted to the top or they will move away from it. They must behave in exactly the same way. How can they tell whether they are at the top of your tube or at the top of my tube? They have no brains and no eyes. The same forces must be acting on them. Can you suggest why they should behave any differently? Are you suggesting that no force is needed in your U tube where a force is needed in my tube?
The answer to this question must contain no mention of trees or sick people or how bad Science teaching is.

We can't get anywhere near your flow system until you justify  something far more fundamental.

You won't answer my perfectly understandable questions about your latest experiment. Why not? Does it threaten your integrity or don't you understand them?

I haven't mentioned your Xylem tubes for ages. I am not interested in your tubes until we get the first bit sorted out. Is it really too hard for you?

I have to explain nothing - you are the one who is making the claims.
I just need some valid justifications for your new opinion - not paranoia.

This is a Science Forum. Why don't you treat it as such? Please apply some logic.
 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 01/11/2008 23:27:07
Andrew
I suggest you try reading through this article and some of the references in it.
www.lps.ens.fr/~caupin/fichiersPDF/CRPhys_2006_7_1000-1017.pdf  (http://www.lps.ens.fr/~caupin/fichiersPDF/CRPhys_2006_7_1000-1017.pdf)

You may find it instructive. If you can read it and understand what it says, it will tell you a lot of what you need to know about trees, the conditions under which tension in water becomes relevant and how cavitation occurs.
Basically, some of your ideas work for trees but they won't work for firemen.
Before anyone thinks they have found something new, it is a good idea for them to trawl through the literature.
Your 'revolutionary' ideas are very fragmented and seem to contain a lot of half-understood notions. Your very worthwhile experiment on the cliffs has been a bit wasted because of your interpretation of the results.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/11/2008 16:39:04
Sophie, before I read the link provided, I have gone back over the Siphon thread to try to understand what your problem with the Brixham Experiment is. Which incidentally is far from wasted! The results from the many experiments conducted, some of which I have not included in this forum, produce the results that they were intended to produce. The problem with being a lateral thinker is one tends to processes problems as a whole, and not segmented so that each can be understood.

You say water would move away from the inside of the tube. As water is already compressed by gravity, where is it going to move to? It can't move down the tube because it is linked to other molecules balancing the downward pull equally on the opposite side of the U tube. It can’t flow out because this would require cavitations to form, again to break the cohesive bond. It can’t flow up because of gravity, It can’t collapse the tube because the wall is strong enough to resist the decompression. If molecules move away from the wall, more molecules must replace it because each molecule acts upon its neighbours. Cavitations will inevitably combine to form larger vapour bubbles and this will cause the water columns to fall back to the level at which atmospheric pressure can sustain them @ 10 metre mark, so although the molecules cannot determine which experiment they are in, we must take into account at all times that each molecule is linked to another inside the tube, so deciding the fate or purpose of a single molecule or groups of molecules that are part of a huge volume of molecules in the same experiment is a little difficult to consider to say the least.

I have now read the lengthy paper you linked to and found it to be a report on the progress of science relating to cohesion, adhesion, tension, surface tension and cavitations in water and other various liquids, dealing with ancient science and more modern science approaches to the problems of cavitations in water. Most of which was familiar to myself, and some of which I have included in the two threads, including the spinning tubes, stretched water, etc.  Nevertheless, I have not seen this paper before and it does include at least two experiments that I have not heard of before. So thank you for posting the link and for taking the time to look at the experiments.

The terminology I use may not always be in accordance with writing a convincing academic argument and I agree with you on this at least, but if you compare what I have stated to what you have provided in the PDF file we are not far from the mark at all.

Throughout the paper you provided, there is no mention of timescales for cavitations to develop in degassed water, although nucleation is mentioned in relation to impurities in water, I suspect the main seed points are indeed between the water/tube interface. I cannot see another experiment that could show timescales for cavitations other than inside a living plant or tree. The U tube gives us prolonged stability of water under negative pressure and tension allowing us to see cavitations developing through the opaque tubing. There must be clearer tubing produced that could allow us to look more clearly at the forming cavitations.

Deionised water previously boiled will enable the Brixham experiment to easily exceed the 24 metre mark and give us prolonged stability.

I thought the inclusion of particles entering the experiment to cause the nucleation was interesting also. And had not considered this.



The following history event shows how a tiny bubble of gas causes the Huygens experiment, (similar to yours), fails from the paper you provided the link to.


4.1. Pull
A straightforward way to stretch a liquid is to pull directly on it. The pull can be generated by the own weight of the liquid. This is how Huygens made the first experimental observation of negative pressure in 1662, and published his work in 1672 [49]. A tube open at one end is filled with water purged of air, and inverted over a water bath. If the air above the bath is evacuated, water remains suspended in the inverted tube. The pressure at the top of the water column of height h is Psat − ρgh, where ρ is water density, and g the acceleration of gravity. As soon as a bubble of air is injected in the tube, it rises and the water column falls. This experiment was presented to the Royal Society of England, and repeated on water and mercury by several physicists, including the famous Hooke and Boyle,
who reached −0.2 MPa in mercury. The phenomenon was later re-discovered by Donny [23] and Reynolds [47,48]. Details are given by Kell [50]. As Reynolds used a 2.3 m-long tube wetted with water before being filled with mercury, he obtained the most negative pressure for water with this method: −0.3 MPa [48]. Hayward, who thought that the method was invented by Donny [23], re-used it to study different liquids [51]. Another way to pull a liquid is to mechanically increase its volume with a bellow for instance. One can also put the liquid under pressure before warming it up, and eventually releasing the pressure. These techniques have been widely used to make bubble chambers where high energy particles are detected because they trigger cavitation in the metastable liquid (see Ref. [53] for a review); however, volatile liquids with a low surface tension were preferred to water. But the bellow method was used by Hayward to design a water pump with a suction lift of 17 m, corresponding
to a pressure of −0.17 MPa [52]; much higher liquid columns exist in tall trees (see Section 7.1).
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 02/11/2008 19:46:25
Saying that you are thinking laterally doesn't prove that you are right.
You have brought up many issues which are very interesting and have changed my views about the behaviour of water under negative pressure.
BUT  the model which is in your head is still flawed. It cannot hope to describe what is going on if you say, for instance, that you have negative pressure up there but gravity is still Pushing the water against the tube. How is that consistent?
A truly valid model has to deal with all the little nitpicking details which you choose to ignore. You cannot be so selective about what you do and don't accept about convention without total rigour. Your explanations for what happens in your experiment just would not extend to other situations - even to a single tube. Your brief experiment was not detailed enough. You won't even answer my reasonable queries about it. You are too confident of your model to submit it to scrutiny. Do you not see how important it is to make clear what was in the void at the top of the tube? If it is air then there must be a leak. If there is water vapor or a vacuum then the void would vanish when pressure increases again. What happened? Can you remember? It is NOT irrelevant if your interest is truly scientific. There is nothing glamorous about pressing on and ignoring these queries and objections.
I despair of ever getting answers to these and the other questions which I and others have asked. If you want to be groundbreaking you have to be totally thorough.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 02/11/2008 22:20:56
The void vanishes each time when the tube is lowered back to ground level due to the compression of the atmosphere. Sorry for not including this as did not realise this was what you were asking. A direct question always helps.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 03/11/2008 10:27:00
I'm sorry; were the following extracts not direct enough?

Quote from my post of  29 Oct:
Your original post did not discuss how the space at the top had formed. Are you suggesting that the gap at the top of the tube was a vacuum? In which case , when you removed your 'extra force', the water would have gone back up to the top (as Galileo et al have found). If the gap remained, then it was full of air. This air can only have got there as bubbles from the bottom, out of solution or via a leak in your 'sealed end.  It must have come from somewhere.
Quote from my post of 29 Oct (later):
How about my question regarding the space that you saw above the column of water? Did it stay there? Was it air? How did it get there?  There is an interesting practical question here.


My comments referred to the single tube - to avoid confusion. It was clearly in that context.  Your last answer seems to refer to the high level U tube experiment. You see, I think that you really don't want the single tube to work because it would go against your theory. However, if you can clear up this problem then I would take that back, of course.

Did you also not read my direct statement that you were wrong when you wrote the tension is the same throughout the column? That needs an explanation from you, I think.

I also made a direct comment, earlier, using chewing gum as a metaphor for water at the top of a tube. No comment about that, either; was it irrelevant?

I just saw this statement from you whilst I was revisiting past posts:
"Stop thinking of water as water, start thinking of it as a solid."
Were you joking?  Can that be taken seriously? At what point do we have to treat a bowl of water as a bowl of solid? You could freeze it - but I don't think that's what you meant. When does a water molecule, at room temperature, know how to treat its neighbours differently? When is it part of a solid and when is it part of a liquid?
 

Can I recap on your recent single tube experiment? As I understand it you used a single tube, less than 10m long and whirled it around to simulate a longer tube. You noticed cavitation at the top whilst it was revolving and this cavitation disappeared when you stopped.  IS this correct?
What was the actual length and at what speed did you rotate the tube? How did you see the effects?

I'm not sure but I got the impression that you repeated this with a U tube and the water ran out. This is what you'd expect because of asymmetry.

Last comment, for now: Could you please define what Density Flow means? I can't find it anywhere apart from in your writings.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 03/11/2008 13:56:20
Sorry but I just spotted this in your last post.
Quote
You say water would move away from the inside of the tube. As water is already compressed by gravity, where is it going to move to? It can't move down the tube because it is linked to other molecules balancing the downward pull equally on the opposite side of the U tube. It can’t flow out because this would require cavitations to form, again to break the cohesive bond.

I was 'indoctrinated' into mechanics when at School, along with Newton's Laws. Forces add vectorially (would you not agree?).
At the top of the tube (when it is >10m, to keep the diagram simple), we have cohesive forces, acting towards all the nearby water molecules and the weight of the molecule, acting downwards. Nothing is being 'compressed by gravity', the molecule is just being pulled downwards by its own weight. The other molecules are all pulling away from it. These all produce a resultant force which acts away from the wall. Unless this force is canceled by an equal and opposite adhesion force, the molecule will move away from the wall. It can only stay where it is when the forces are balanced. Can you possibly disagree with that?
When this molecule moves away, it, of course, would let all the other molecules move - they are under tension- and they can flow out of the bottom of the tube as long as there is an unbalance in the forces.
Unless you have adhesion - not just a bit, but of equal value to balance the other forces involved - the bead will part company with the wall. If you don't agree with that then you need to go away and learn the basics of how forces work.
Needless to say, this applies to any shape of container, be it U tube, or an upside down Poseidon in the well known film.
You don't have to pick me up on this example because, in that case, the adhesive forces are not enough AND cavitation will occur. But that isn't the point of the argument.  The point is that, if the column stays up, it must involve both 'strong' adhesion and a delay in cavitation.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 03/11/2008 14:22:12
A density flow is what it says it is. Density flow is the movement of a denser solution acted upon by gravity from an elevated point towards the ground, which in turn induces a return flow. So it is a flow and a return flow system. This simple density flow is what drives a non-pumped domestic hot water system. The heat source alters the density of the water causing it to rise. The copper coil inside the hot water tank causes the water to become denser as it transfers the heat from the tube to the water inside the tank, causing it to flow back down to the source of heat, where the circulation process continues. A self circulation heating system operates by the force created by the density difference between the hot and cold fluid.

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.engineeringtoolbox.com%2Fdocs%2Fdocuments%2F189%2Fgravity-heating-system.png&hash=2366a04d130ca2aac38af48b4d47a265)

 A video on Youtube shows the flow through a clear glass vase. Watching it you could easily miss the point that for a downward flow of denser solutes, there must be a return flow to the surface, water molecules will always move to where molecules have moved from, just the same as they would when molecules move away from the inside of the pipe.

Your post asking about the void related to the single capped tube. I said that water flowed out of the tube when the experiment was performed, so could not have returned to fill up the void.

Damn, just realised a mistake with that capped experiment.  Maybe if we have a single capped end of tube and the open end in a vessel rather than being exposed to the air will assist the water to resist the centrifugal force longer. This would require affixing the bottle in some way to the end of the tube to prevent it from flying off.

There was no point swinging round a U tube in the same way because water would not remain in it. Again however if the both ends of the tubes were in a container and it was swung round it may prove interesting.

The chewing gum analogy necking, I did mention that as one molecule moves away from the wall of the tube another will replace it providing of course that the cavitation is not sufficient to cause the bead of water to fail.

Popping out so will get back to this on return
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 03/11/2008 15:51:28
OK on the term 'density flow'. In a hot water (convection) system, the energy comes in the form of thermal energy. To keep it going you need to keep the energy flow by maintaining a temperature difference.

Quote
The heat source alters the density of the water causing it to rise.
That's schoolboy howler number one. Water will not rise unless it is pushed. There are no strings pulling it up. What pushes it? It is the more dense cold water which displaces it.
Andrew, if you are not thorough with well known matters like that then how can you hope to make any worthwhile advances in Science?

Quote
Your post asking about the void related to the single capped tube. I said that water flowed out of the tube when the experiment was performed, so could not have returned to fill up the void.
So what was in the space over the water? If there was a permanent 'void' at the top then it must have been AIR! That means either a leak into the top or bubbles floating up from the bottom. I wish you could explain exactly what happened. It certainly casts doubt on the experiment.

Quote
water molecules will always move to where molecules have moved from,
Here's another cause and effect problem. The more dense solution displaces the less dense. Why? Because the more dense is pulled down harder than the less dense and pushes it out of the way. When you add the solution, you increase the overall pressure at the bottom of the container.
How does that apply to molecules as they move from the surface when water evaporates? You imply that you would get 'strings of water' leaping up into the air.

Quote
I did mention that as one molecule moves away from the wall of the tube another will replace it
And where does this molecule come from?  Does there have to be a flow? Do you inject them into the top? Get your model sorted out; it really is dodgy. Or are you only considering the situation when you have enough gum flow to allow the molecules to come from the other side? You are implying that there is a minimum speed at which this would work. Any slower and the gum will 'neck'. My diagram applies to the gum just the same as the water. Are you arguing with the basics of force vectors?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 03/11/2008 19:04:15
Sophie. Why do you mock?  In my density flow tube, we clearly see one side of a soft walled tube pulled in and one side bulging out. We clearly see water leaving one vessel into another and the same goes for a closed loop of tubing.

Your statement that water will not rise unless it is pushed may need a little edit, else you will have the entire cohesion tension fringe of science after you. They state as one molecule leaves a leaf (scuse the pun)  another is pulled behind it to replace it and this believe it or not is largely accepted science and all science has to offer with regards to the ascent of sap in tall trees, perhaps you should take a leaf out of their books?

And yes there are strings pulling on the fluid, strings of particles linked together just like RD suggested in his chain analogy. Using food colouring we can see how the flow occurs, we do not see a uniform full bore flow but a considerable amount of turbulence as some of the coloured salt solution is flowing down the return flow side of the inverted U tube which rolls in a circular motion as salt free water is drawn past it. Fascinating to watch by the way and well worth studying. It shows how molecules pull on each other too. What do you suggest might be pushing water out of the top of a giant sequoia towering well over a hundred metres? Root pressure? Magic?

The central heating system shown was merely to illustrate that a downward flow will result in a return flow. But more to the point to coin one of your phrases; ‘How do molecules of water know they are in a U tube, a central heating system, a single upright capped tube, a tree or indeed a human ’? Why should we expect that an upward flow or downward flow inside a tree will not produce a return flow? Schoolboy stuff this, but before the education system gets in their way!

And let us not forget your meniscus example where adhesion is pulling the water up at the edges, or have you forgotten this argument already?

I have not said there is a minimum flow at which this will work. I have said that we have an excellent opportunity to study cavitation in this model due to it’s stability and this is the first time the speed at which cavitation takes place in water suspended in a meta-stable state. There is another thing I would like to add. It would appear that cohesion is taking place in the upward flowing leg of the suspended tube. I may certainly have missed some cavitations forming in the 24 meter’s of water filled tubing on the down flow side, but suspect that the saline flows, which represents the phloem in trees is repairing the voids? Or is the positive pressure evident by the outflow from the bottle at ground level sufficient to prevent them from occurring in the down flow side? Even the bench top model produces cavitations over time.

The rotating tube failed because the open end allowed all the water to come out of the tube emptying it completely so unable verify if there was void in it or not.

To conduct a 24 meter single tube experiment would be a pain in the back side. Have you ever tried filling a six mil bore tube with water and making sure there are no bubbles in it, that is capped at one end? I have, and will not be attempting to fill a 24 meter one.


OK on the term 'density flow'. In a hot water (convection) system, the energy comes in the form of thermal energy. To keep it going you need to keep the energy flow by maintaining a temperature difference.

Quote
The heat source alters the density of the water causing it to rise.
That's schoolboy howler number one. Water will not rise unless it is pushed. There are no strings pulling it up. What pushes it? It is the more dense cold water which displaces it.
Andrew, if you are not thorough with well known matters like that then how can you hope to make any worthwhile advances in Science?

Quote
Your post asking about the void related to the single capped tube. I said that water flowed out of the tube when the experiment was performed, so could not have returned to fill up the void.
So what was in the space over the water? If there was a permanent 'void' at the top then it must have been AIR! That means either a leak into the top or bubbles floating up from the bottom. I wish you could explain exactly what happened. It certainly casts doubt on the experiment.

Quote
water molecules will always move to where molecules have moved from,
Here's another cause and effect problem. The more dense solution displaces the less dense. Why? Because the more dense is pulled down harder than the less dense and pushes it out of the way. When you add the solution, you increase the overall pressure at the bottom of the container.
How does that apply to molecules as they move from the surface when water evaporates? You imply that you would get 'strings of water' leaping up into the air.

The moecule I mentioned was a water molecule, so presumably it would have come from the water inside the tube.

Quote
I did mention that as one molecule moves away from the wall of the tube another will replace it
And where does this molecule come from?  Does ther have to be a flow? Do you inject them into the top? Get your model sorted out; it really is dodgy. Or are you only considering the situation when you have enough gum flow to allow the molecules to come from the other side? You are implying that there is a minimum speed at which this would work. Any slower and the gum will 'neck'. My diagram applies to the gum just the same as the water. Are you arguing with the basics of force vectors?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 03/11/2008 19:48:35
We have a U tube filled with degassed water to add stability. Adhesion must apply to the entire length of wetted inside of the strong nylon tubing. I agree so far at least. The molecules are all happily stuck fast to the tube. Still with you here so far. It can be as strong as you like and I am entirely happy with this and indeed it is perfectly logical and obvious. In fact I would go so far as to say the water stuck to the inside of the tube forms it’s own water tube. This provides an environment for water to flow either way in this suspended tube providing it is below 10 meters. If we pull both ends out of the water below 10 meters water flows out one side and the other side is emptied out of same side as it is pulled around by the out-flowing water, just like a syringe draws water from a vessel. So the water molecules involved in adhesion do not prevent free movement through the tube, but do prevent the water inside from necking, as in your chewing gum analogy. Above the 10 meter mark we do not have gravity pushing down and the atmosphere, which in turn pushes down on the water in the open vessel that in turn forces water up the tube or in this case assists it to stay there below the vacuum / void point.

So there is an attraction to the wall of the tube and molecules should align to the tube to form adhesion by using the opposite polarity to the nylon tube molecules-whether this is relevant at the moment I’m not sure. Nevertheless water can flow out either side of the tube, so adhesion does not prevent the outflow in the U tube. So cohesion must be the main stabilising force. What I hope I have said here is that although the water is stuck to the inside of the tube, water can move freely it does not arrest the water column so cannot be responsible for holding the open ended water filled tubes that we have exposed to the atmosphere by removing them from the water. So why does the water not flow out? What explanation other than the elasticity of water which is related directly to the cohesion of water will account for the water rapidly rising up the exposed tubes forming a level a considerable distance from the ends of the tubes?   
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 03/11/2008 21:03:32
Andrew. You are in your own little Science Cloud Cuckoo Land, I'm afraid. Three is just no point in continuing with this. You are not even aware of how much Science you are rejecting.
Over and out.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 03/11/2008 23:08:44
You can't have it both ways either the water is stuck to the tube or it is not. But only the molecules closest to the tube count. The rest of the water does not come into contact with the tube so relies on cohesion and is therefore free to flow either way but not without having an affect on the molecules next to those that are flowing. The question is really why don't you repeat the damned experiments and draw your own informed conclusions, rather than summising what you think must be happening?

By the way cloud Cuckoo land is way above 24 meteres vertically. And unlike the cohesion tension theory you et al adhere to, it does not suck.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 05/11/2008 11:02:03
I'm sorry but your last post, as they all tend to, consists of a non-logical, circular argument. I just can't cope with it any more.
Thoroughly examine what you have said.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 05/11/2008 15:42:32
Sophie I don't know how to put it into words that you can understand. Trying to say that even if the molecules are stuck to the tube it does not prevent freeflow from the tube as observed below 10 meters, if that makes sense. So adhesion while important is simply not as important as the cohesion in water molecules which is why the Brixham experiment works. My work is logical and has convinced a lot of professional people at professor level. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 05/11/2008 19:22:47
Of course the water can flow - it's a liquid. But what you ignore constantly is that, if there is no adhesion then it will leave the wall (it will flow away from the wall). You talk about water 'flowing in' to to make up the space but where will it come from? From which side? It will merely form a neck because each of your down tubes pull it in different directions. You are surely not suggesting that there is enough velocity in the flow to keep it moving, are you. It doesn't have to flow to work, in any case - you say.
Don't you see the very basic inconsistency in your version of what goes on at the top?
Give it some serious thought.
A rope can be as strong as you like but if you don't tie it on, it comes adrift. The molecules at the interface are the only thing which can keep the water in place up there - if you detach them, the column will pull apart due to necking.
Are you saying that a smooth bore metal tube >10m would work also? It is known to have lower adhesion to water than  water cohesion, remember.
Let's face it, you have assumed that the single tube will not work on the grounds that you believe you have an explanation how the U tube works. That is a totally circular argument and can't prove anything. You are totally locked into this misconception and have given no justification for it.
You have yet to answer a lot of my objections to your basic Science statements - like the tension in the column being the same. Any comments?
There - you've started me off again - blast.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 06/11/2008 08:58:58
I did reply to your question about tension being the same throughout the columns of water on both sides. Tension is applied to every single water molecule. This dragging effect was realised by Professor H.T.Hammel, ever wrote a paper on it relating to how current understanding of osmosis is totally wrong. Dissolved solutes apply the tension as they move from one point to another due to the effects of gravity and in doing so cause the whole of the liquid to move in the direction of flow. One would think that the bead of water breaks because the tension is greater in the area that breaks. But this is not entirely accurate. Cavitations take place along the column of water rather than just at the top. It is the tiny cavitations that join together that eventually cause the columns to separate and the levels to return back to the 10-meter mark.

When I conducted these experiments, I did so because everyone else had assumed there was no point because of historic experiments with water in tubes. Clearly they were wrong. The experiment you keep trying to justify is the very same experiment that has failed for 300 years. Modifying it slightly may as you say improve the possibility of prolonging it before it collapses, and as it is your idea then it is you that should test it. As I have said it is a pain filling a closed loop tube with a liquid. But having thought about this it could prove easy to do with a smaller tube inserted inside the 6 mil tube to push water in under pressure right to the end, withdrawing the inner tube as the water is injected. The tube would need to be relatively stiff to be able to push it right to the closed end of the 6 mil bore 24 meter tube.

The justification I have given to the U tube experiment is that it clearly does work, even when scaled down.

Remember. The U tube experiment was relating to the shape of vessels in nature. Trees do not have tall tubes that flow up to the top and end, they have circular vessels that entertain a circulation, something worth remembering.

A lot of people are reading this thread, would anyone else like to add their thoughts on whether a single capped tube would cause water to remain inside at 24 meters or even above 10 meters? The end of the tube should be globe shaped or rounded and smooth. Are there any schools or colleges interested in performing this experiment in the name of science?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 06/11/2008 14:38:56
So you are saying that the force on the bottom link of a hanging chain is the same as that on the top link?
What about the weight of the chain? This is the most elementary mechanics and doesn't need to refer to Prof Hammel or osmosis. That is just a smokescreen.

What you say about tension is merely an unsubstantiated statement - not a reasoned argument. Solutes will tend to fall because they are more dense. A stone will do the same thing in water.

You have no proof that the U tube is any different from the single tube because you have not done a control experiment. Yes, it would be a pain but, without it, you have not proved a difference. You are the one who needs to prove it - not me; those are the rules, I'm afraid. Old ideas are "Innocent until proved guilty."

You can't seem to deal with my 'necking' / adhesion argument and what would happen at the top if it weren't for adhesion so I presume you have no answer.

I would have to decline your kind offer to demonstrate your ideas to a bunch of innocent Schoolkids because your whole methodology is flawed. They could really do without that sort of influence until they are equipped with some logical thinking skills.
"In the name of Science"?? What Science? Science is consistent - or aims to be so. You have introduced an inconsistent idea which is not proven. You just get upset when it is not accepted.
Give me a good, logical, argument which refutes the logic of how the column of water would not stay up there unless stuck to the tube. And would it work in a metal U tube?

We have already accepted that your experiment worked. That is an interesting and surprising result. It's your explanation which is not acceptable because it does not stand the logic test. The one doesn't follow from the other.

And 'scaling down' is not valid because you have not scaled the ambient pressure. Can you argue with that?

Quote
Remember. The U tube experiment was relating to the shape of vessels in nature. Trees do not have tall tubes that flow up to the top and end, they have circular vessels that entertain a circulation, something worth remembering.
Can you repeat that in a way that makes sense, please? Tubes don't flow. Which are the circles? What does "entertain circulation" mean?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 06/11/2008 21:27:34
Put another way: The sap that flows in the tree is not on a one way trip to atmospheric liberation, it circulates around the tree evaporating water from it to the atmosphere, just the same as we do not excrete blood unless wounded, a tree does not excrete sap but evaporates solute free water from the sap.
Can see I missed some words from the last post now sorry.

I know this conversation has become heated at time. I just want to say that I am grateful for your thoughts even if at times I appear to be unhappy with some of your less than civil comments. The original explanation for the tubular experiment was written for students at Junior and secondary level in order to introduce the concept of a flow and return mechanism, without clouding it and making it too complicated for them to understand it. I still feel I did a good job regarding this and had no problem convincing both students and teachers with the experimental model and indeed the flow and return argument in trees.

I am beginning to take on board that a more detailed explanation is required for eventual publication, and as you say the need to test a single tube, a metallic tube, a plastic tube filled with mercury etc etc. I am also beginning to understand, thanks to you and others why a simple explanation may prove too problematic for people to grasp the behaviour of stretched fluids without seeing it for themselves, again thank you for enlightening me on how this is interpreted by others.


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 06/11/2008 22:52:37
That's OK as far as it goes Andrew.
I see that you are totally convinced that your Science is correct.
It is not 'too problematic' for me to understand what you are saying. It is 'too problematic' for me to accept it. There's a big difference.
As I have said several times. Your experiment show evidence of a phenomenon which is novel but your explanation is just too naive. I don't need to see it for myself. I believe you saw what you saw.
I also believe in well founded Science. Results, in general, agree very well with the established theories.  You, apparently don't understand these theories or you would be looking for an explanation for your phenomenon amongst them, rather than making up your own incomplete one.
Science tries not to be a matter of opinion; we try to base it on rigorous logic. When someone brings up an objection, for instance, based on vectorial addition of forces the objection has to be answered with rigour. You have chosen not to consider how this shows flaws in your explanation. If you explanation were correct, you could explain such an apparent anomaly.
You seem to be leaving this dialogue, assuming that you are, in fact right and ignoring objections.
Please don't have the temerity to object to conventional Science teaching on the grounds that we tell kids to believe things "because we say so". That is just what you have been trying to do -and with far less justification and track record. If a student objects to any of the standard Science I present them with, I am in a position to justify it right up to the wire. I would not dream of belittling them merely on the grounds that they have 'interpreted it' wrong. I will give them a full and rigorous explanation after having worked, if necessary, for a long time to reconcile their ideas.
I see you regard yourself as a heroic figure, battling against the massed ignorance of the Science establishment.In fact you are a Don Quixote, tilting at Scientific Windmills and failing to see what is actually going on around you.
Please try to read some established texts. They cannot all be wrong in every respect so they may just be more right than you are about this topic - if only you could understand what they are really saying.
It's never to late for some independent learning and self education. I do it every day.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/11/2008 14:04:00
Transpiration-Pull http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/X/Xylem.html

In 1895, the Irish plant physiologists H. H. Dixon and J. Joly proposed that water is pulled up the plant by tension (negative pressure) from above.

As we have seen, water is continually being lost from leaves by transpiration. Dixon and Joly believed that the loss of water in the leaves exerts a pull on the water in the xylem ducts and draws more water into the leaf.

But even the best vacuum pump can pull water up to a height of only 34 ft or so. This is because a column of water that high exerts a pressure (~15 lb/in2) just counterbalanced by the pressure of the atmosphere. How can water be drawn to the top of a sequoia (the tallest is 370 feet high)? Taking all factors into account, a pull of at least 270 lb/in2 is probably needed.

The answer to the dilemma lies the cohesion of water molecules; that is the property of water molecules to cling to each through the hydrogen bonds they form.


When water is confined to tubes of very small bore, the force of cohesion between water molecules imparts great strength to the column of water. Tensions as great as 3000 lb/in2 are needed to break the column, about the value needed to break steel wires of the same diameter. In a sense, the cohesion of water molecules gives them the physical properties of solid wires.

Because of the critical role of cohesion, the transpiration-pull theory is also called the cohesion theory.
Some support for the theory

    * If sap in the xylem is under tension, we would expect the column to snap apart if air is introduced into the xylem vessel by puncturing it. This is the case.
    * If the water in all the xylem ducts is under tension, there should be a resulting inward pull (because of adhesion) on the walls of the ducts. This inward pull in the band of sapwood in an actively transpiring tree should, in turn, cause a decrease in the diameter of the trunk.

         * The rattan vine may climb as high as 150 ft on the trees of the tropical rain forest in northeastern Australia to get its foliage into the sun. When the base of a vine is severed while immersed in a basin of water, water continues to be taken up. A vine less than 1 inch in diameter will "drink" water indefinitely at a rate of up to 12 ml/minute.

      If forced to take water from a sealed container, the vine does so without any decrease in rate, even though the resulting vacuum becomes so great that the remaining water begins to boil spontaneously. (The boiling temperature of water decreases as the air pressure over the water decreases, which is why it takes longer to boil an egg in Denver than in New Orleans.)
    * Transpiration-pull enables some trees and shrubs to live in seawater. Seawater is markedly hypertonic to the cytoplasm in the roots of the coastal mangrove, and we might expect water to leave the cells resulting in a loss in turgor and wilting. In fact, the remarkably high tensions (on the order of 500–800 lb/in2) in the xylem can pull water into the plant against this osmotic gradient. So mangroves literally desalt seawater to meet their needs.

Problems with the theory

When water is placed under a high vacuum, any dissolved gases come out of solution as bubbles (as we saw above with the rattan vine). This is called cavitation. Any impurities in the water enhance the process. So measurements showing the high tensile strength of water in capillaries require water of high purity — not the case for sap in the xylem.

So might cavitation break the column of water in the xylem and thus interrupt its flow? Probably not so long as the tension does not greatly exceed 270 lb/in2.

By spinning branches in a centrifuge, it has been shown that water in the xylem avoids cavitation at negative pressures exceeding 225 lb/in2.

Sequoias can successfully lift water 358 ft (109 m) — which would require a tension of 270 lb/in2.
However, such heights may be approaching the limit for xylem transport. (The tallest tree ever measured, a Douglas fir, was 413 ft. high.) Measurements close to the top of the tallest living sequoia (370 ft high) show that the high tensions needed to get water up there have resulted in:

    * smaller stomatal openings, causing
    * lower concentrations of CO2 in the needles, causing
    * reduced photosynthesis, causing
    * reduced growth (smaller cells and much smaller needles).
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 07/11/2008 15:43:30
Facts quoted above, from others, could well be true.
It is your interpretation of them that is flawed.
Merely posting yards of interesting botanical information does not detract from the fact that your Science is wrong.
As usual, you have no answers to the more searching questions.
Give my regards to Sancho Panza.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/11/2008 17:08:50
Whatever
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 07/11/2008 23:20:51
Interestingly, nowhere in your recent long post do you quote anyone denying the effects of adhesion. Nor do you quote anyone even hinting at your U tube theory.
It's just a re run of the previous stuff about the cohesion in water being very high, on occasions. A bit pointless as I have already agreed that the evidence for cohesion is compelling.
It's your personal interpretation that needs explaining and justifying.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/11/2008 09:13:11
1.  No tree to my knowledge has a cap on the top.
2.   Circulation in a tree flows predominantly down in the phloem from source to sink. Source being leaves, sink being lower than the leaves.
3.   Evaporation from the leaf cannot take place without a change in density in the sap that flows through the leaves. It is bad science to ignore this fact!
4.   The model we are debating while interesting is merely an experiment that was designed to show the power of a flow and return system that benefits from gravity, not to reflect the perfect anatomy of a tree.
5.   I have never denied adhesion is important. The fact that I never mentioned it by name, but did mention it by including that a soft walled tube necks as the tension is applied, based on observations with other experiments using soft walled tubes, and further mentioning it in the varicose veins study again a soft walled tube behaving in exactly the same way as my experiments is not the bad science you purport it to be. I have said that adhesion relies on cohesion but cohesion does not rely on adhesion, including that even when water is stuck to the side of a water filled conduit, it does not arrest the flow of water through the conduit. Yet in a single upright tube capped at the top this is what will happen and water inside the tube will be pulling down against the top of the rounded capped tube. Adhesion inside the vertical single tube will enable cohesion to be pulling inwards and downwards. Adhesion is not therefore a force, the force is the body of water on the molecular bonding between the water / tubular interface.
6.   And what if? What if I jump through your hoop, conduct your experiment and prove it one way or another? What have I accomplished? Who is going to listen? Does this mean it will become accepted?
7.   Or does it mean that you et al will find yet another reason to continue to believe in the leaf sucking cohesion tension impossibility of the first degree?  Come on here, play devils advocate for an hour or so and see through their smoke and mirrors theory. Leaves cannot suck water up a tree, no matter what spin is put on the theory it is still completely and utterly flawed.

The longer last post did provide you with evidence towards answering your many questions. It relates to the strength of cohesion, includes adhesion in exactly the same way I included my mention in the necking of tubes, It includes the vine experiment showing water boiling at ground level due to the tension applied in the stem, proving that tension occurs throughout the column of water as I had said it would do. And observed it doing as tiny vapour cavitations formed along the length of suspended tube, and go back into the water when the tube is lowered.

It mentions also the spinning / centrifuging of branches to test the cohesion which reflects the tubular experiment I swung round carefully. Although this needs to be done again with a water filled bottle on the end of it to produce a compared tension. Remember the tube used will easily withstand the crushing force.

I do not see many people rushing forward to defend the existing theory. Many thousands of people have read this thread now. Why do you think this is so? And finally the required tension of a giant sequoia at 270 pounds per square inch. Impressive tension that. If it is in place someone should have measured it by now?


Ulrich Zimmerman.
The Cohesion Theory considers plant xylem as a 'vulnerable pipeline' isolated from the osmotically connected tissue cells, phloem and mycorrhizas living in symbiosis with plant roots. It is believed that water is pulled exclusively by transpiration-induced negative pressure gradients of several megapascals through continuous water columns from the roots to the foliage. Water under such negative pressures is extremely unstable, particularly given the hydrophobicity of the inner xylem walls and sap composition (lipids, proteins, mucopolysaccharides, etc.) that prevents the development of stable negative pressures larger than about −1 MPa. However, many plant physiologists still view the Cohesion Theory as the absolute and universal truth because clever wording from the proponents of this theory has concealed the recent breakdown of the Scholander pressure bomb (and other indirect methods) as qualified tools for measuring negative pressures in transpiring plants. Here we show that the arguments of the proponents of the Cohesion Theory are completely misleading. We further present an enormous bulk of evidence supporting the view that – depending on the species and ecophysiological context – many other forces, additional to low tensions, can be involved in water ascent and that water can be lifted by a series of watergates (like ships in staircase locks). http://www3.interscience.wiley.com/journal/118760238/abstract?CRETRY=1&SRETRY=0
I have asked Ulrich if he would like to take a look at this thread and add a comment.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 08/11/2008 09:46:41
In case you hadn't noticed, the reason I keep asking the same question is because you have not answered it yet.
You have just replied with more acres of stuff from other people and with second hand arguments which don't deal with the issue.
My question is, and has always been, to you personally.
Like a cabinet minister under tight interviewing, you have still not answered it. I have no strong opinions about the stuff you have just written about. I just want to know, in terms of the actual science, how you can still insist on the difference between your U tube, which you have tried and my single tube, which you haven't tried.
Not one of your references deal with that.
Your replies would only need to be a couple of paragraphs long if you were to stick to the issue.

Yes, there have been thousands of visits to this and the 'siphon' thread. The only recent contributions, however, have asked you to answer my question. You still haven't.

Perhaps an honest reply would be that you don't understand enough of it to explain the phenomenon thoroughly. There would be no shame in that.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/11/2008 11:23:31
Your experiment idea is a test of adhesion, and yes I do understand why you feel this may be strong enough to support the water. But this experiment has been conducted my many people over many years using many different materials, all of who have failed just like the great philosophers of science did over 300 years ago. If it were to succeed what then? Would this change my own experiment one bit? Not a chance, because as I have said and will say again the experiment performed as it was expected to perform and water was observed to flow around it from one vessel to another. The fact that you have a problem with what goes on at the molecular level inside a U tube compared to the inside of a capped end tube is fascinating but hardly going to destroy my own observations whichever way it goes is it?

You keep trying to throw a protective shield around students steering them from what you see as heretical science. But then fail to address the flaws in the accepted science.

Adhesion inside the tube is an obvious stabilising force preventing the water from pealing away from the walls of the tube. The downward force of the column of water pulls on the water molecules in the opposite side of the loop of tubing, which in turn balances out the opposing force enabling the water to become stretched by the weight of the two columns of water. The water inside your capped tube can only be stretched to the point that the water is able to stick to the capped end of the tube.  We are talking about 6 mil bore tubing here, not some micro-bore capillary tubing.

I have not tested the experiment with metal tubing, and do not have access to a 48 meter length of unblemished metal tubing do you know where one could be found? Remember soldered joints will provide nucleation sites so can’t be used.

You have failed to answer my questions on paragraphs six and seven. I would like you to answer them if you feel you can. Is there going to be an opened door at the end of it and if so can I have it in writing please.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 08/11/2008 19:02:47
Quote
Your experiment idea is a test of adhesion, and yes I do understand why you feel this may be strong enough to support the water.

"MAY BE"??? I am saying, with better logic than any single one of your own 'original' ideas, that the adhesion has to be equal or greater than cohesion for your U tube or a single tube to work. If you can't understand my reasoned argument for that then that is your problem.

Quote
You keep trying to throw a protective shield around students steering them from what you see as heretical science. But then fail to address the flaws in the accepted science.
The problem is that your 'Science' is not even complete enough to be heretical.
I would protect them from what you have said so far in the same way that I would urge them to take care when reading adverts for snake oil and lunatic political parties.

Yes, I would say that any theory which ignores the simplest bit of vectorial force addition was nonsense. You do not even realise that what you are saying fails in this respect. You are implying that
"Forces Add Vectorially Except at the Top of a U Tube. In this situation we can ignore that particular bit of Science". 
Is that  supposed to be serious Science?
Describing the adhesion as a 'stabilising force' is to show that you don't understand the whole basis of vector addition. Why not use the proper terminology - which keeps bridges and planes up in the air and allows people to do Physics, Engineering and Chemistry with great success. This is not new Science and it is really not open to debate - certainly not by someone who seems not even to understand it. (Do you understand the 'triangle of forces' and what it implies in this context?)


Paras 6 and 7: I would fully expect the single tube to behave the same as the U tube but, as you say, it is more difficult to implement. It is you who claim that it wouldn't work on grounds which just demonstrate that you don't understand the basics.

You can buy long rolls of annealed copper tubing (10 mm microbore) in very long lengths. You would find it difficult to do the same experiment, though. I guess you would have to detect the amount of water suspended in it by weighing it. Adhesion between water and metals being what it is, I should expect the 10m limit would apply, so you could prove it one way or another with 21m of tube.
Smoke and mirrors? Can you show in a rigorous way how any aspect of modern Science is just Smoke and Mirrors? This is another of your Windmills.
Where do you get your ideas about the Science establishment. You put me in mind of Jude the Obscure, who was rejected by the Establishment in the Distant University City because he had tried to educate himself and had actually GOT IT WRONG. He was the only one who was surprised at what happened.
Give a Scientist, who is worthy of the name, a good reason to think that an existing theory is wrong and  he will bust a gut trying to PROVE it is wrong. He won't rant and rave that the system is flawed and that everyone is being horrible to him. He will scrutinise the new idea and try, in an informed way, to get the right answer.
 Clearly, you think your education in Science gave you a bad deal; that's sad but, unlike after a war, it is the losers who try to write the history. Mine certainly gave me a very good deal and I learned a lot throughout my life; it continues. What I did learn at a very early age is that if you can't answer a question you admit it and ask for help.

Quote
The fact that you have a problem with what goes on at the molecular level inside a U tube compared to the inside of a capped end tube is fascinating but hardly going to destroy my own observations whichever way it goes is it?
Do you actually read what I have written?
My idea does not attempt to destroy your observations - it successfully destroys your INTERPRETATION of them. Can you find, anywhere in this or the Siphon thread, a comment of mine which casts doubt on your observations?
Do you really want to ignore what happens at the molecular level and how the most basic bit of mechanics applies? It's a bit too rigorous and hard-fact for you, perhaps.

What you are basically saying is that you are right because you say so and the whole of Science is out to get you and your teachers were rubbish.
That's an opinion but proving the Science is a bit more involved than that.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2008 09:14:42
Ive found a supplier of 50 meter micro-bore copper tubing, cost £88.62 including VAT.
http://www.mytub.co.uk/product_information.php?product=309455

Maybe your school might be interested in testing both models? I can supply the school with the plastic pipe for free.

RE Smoke and Mirrors and Snake Oil Salesmen. First of all Proper snake oil from the water snake has some very interesting properties. The problem arose when Westerners jumped on the bandwagon selling inferior products that used the success of the original oils to market their own oils. Either way someone gets paid. I get paid nothing for this research. So the innuendo you implied is unwarranted.

On BBC Radio 2 this morning a Professor was talking about new Statins, based on speculative trials, he was deliberately trying to increase the market share for what he implied was a new wonder drug. It allegedly reduces the risk of stroke and heart attacks in people who do not have a problem with stroke or heart attacks. His company has identified that the entire human race should be medicated with this new wonder drug and the National Health should but can’t afford to pay the many hundreds of millions of pounds required to get the whole of the UK popping pills.

He referred to NICE in an obscured way saying that they advise the use of statins in certain cases. This was very deceptive of such a high ranking academically qualified professional. Not a single mention of any contraindications ether, one would have thought there may be some if a large scale study over say 10 years or more had been conducted. After all Statins are known to have contra indication.

Will you be advising your students against listening to the real snake oil sales-people?
Quote
"Doctors unhappy : http://news.bbc.co.uk/1/hi/health/7326870.stm
Dr Peter Trewby, a consultant physician at Darlington Hospital who has studied how willing patients are to take preventative medicines like statins, believes we are already prescribing too many statins.
He said: "We are turning healthy people into patients, we are medicalising people and making them worry about their health unnecessarily.
"I would take a statin if I had a heart attack but I certainly wouldn't take on otherwise."
Many GPs have told The Investigation they feel that they are being pressurised to prescribe statins to patients some of whom have almost no chance of benefiting.
Dr Stephen Fox, a GP from Leigh in Lancashire became so worried by the level of side effects he was seeing in his elderly patients that he is asked the NHS if there was any research evidence on statins and the over-75s.
He was told there was none.
He said "At some point you have to ask where is the line going to be drawn - does absolutely everybody have to be on these?"
Lunatic political parties attack countries that are unable to defend themselves, blow them to bits with high tech weapons massacre men women and children that have no interest in war or politics in the name of Oil, Sorry "weapons of mass distraction"!
 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 10/11/2008 09:33:27
What has all that got to do with my fundamental question?

I would advise my students not to listen to someone who wouldn't answer a direct question.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2008 17:14:08
Fascinating experiment showing a slice of water inside a solid wire frame.
Surface tension in water relies on cohesion in the water molecules. A droplet of water exhibits contraction of the surface water molecules due to cohesion pull. The following experiment in micro gravity shows graphically that:

1.   water does adhere to a metal wire. It also shows how water in micro gravity forms a globe. What does this suggest about the proposed copper tube experiment?
2.   The film of water shows the strength of cohesion and its stability is mentioned in hours rather than seconds. (that’s pretty strong)
3.   Not sure what the vanishing bubbles added to the water film tells us yet, but it certainly is interesting and could show graphically how cavitations are dealt with by trees.
4.   The paper towel used to draw water away from the captured water globule again shows that the adhesion to the wire does not affect the water’s ability to be drawn from the captive globule. So although adhesion is holding the water to the wire and the molecules of the water are under tension, the water can still be drawn away while the cohesive bond between the thin fim of water molecules resists the tendency to part even when other materials are added.
5.   The flow within the film of water shown by adding colouring is interesting, but unable to deduce whether there is some gravitational influence from the Earth, moon or even the mass of the station.

Micro gravity is a good tool for allowing us to see how water exists inside the tube here on earth.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2008 17:42:16

This video shows how strong the cohesive bond of a thin film of water really is subjecting it to boiling from a soldering iron and still it does not fail.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 10/11/2008 18:02:56
Never a straight response.
Are you surprised I wouldn't invite you to my School?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 22/06/2009 09:19:09
How do trees really lift water to their leaves?
Author: Andrew K Fletcher

The arguments for accepted explanations for fluid transport in trees has not been forthcoming, in fact this thread has shown they are indeed flawed.

Ever thought about how Giant Trees towering over a hundred metres can raise water to their leaves without an obvious pumping mechanism?

It may interest you to know that the current explanations are nonsense.

Take root pressure for example. Do roots really squeeze water to the tops of trees? Or Capillary action. Can trees soak up water and release it into the atmosphere like a giant sponge, if this were the case, rising damp would ooze from the tops of walls and even tall buildings? The Oceans would infiltrate the soils and ooze out at a higher level than the ocean.
The Cohesion tension theory as it stands sucks! And relies on water leaving the leaves and this is thought to somehow drag on a chain of water stretching right to the roots. (elaborate way of saying sucks)

Imagine standing on a desk let alone a hundred meters in the air and trying to suck water up a straw from a bottle on the ground. We can't do it so why do we expect a tree to be given different rules? It goes on to say that the huge number of leaves cause a collective pull. Well there are plenty of trees that stand at impressive heights, that are not furnished with a huge canopy of leaves and yet are able to effortlessly draw water from the soil and absorb moisture from the air. The larch being one example. But what about deciduous trees. In the Autumn the leaves fall and yet somehow in the spring the tree picks up where it left off and circulation continues inside causing the buds to form. How does this fit with the leaves having to pull water up? And then Straburger’s experiments where he killed a tree suspended vertically in a bath of picric acid. Strasburger observed circulation continuing for several weeks after the tree was completely killed ruling out living processes.


For those out there that continue to adhere to these quaint proposals for the ascent of sap in tall trees, namely root pressure, the cohesion tension theory, osmosis, capillary action, They are WRONG!

The trees circulate fluids, they do not have a preposterous one way fluid hoist system, but a circulation driven by density changes caused by evaporation altering the sap within the leaves and branches not unlike our own circulation which also benefits from density changes in the fluids again caused by evaporation.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 22/06/2009 11:10:25
I'm very happy with altrnate theories but why try and improve on osmosis?  Surely it explains everything?  I'm not sure that ANYTHING need be added to this process.  It's just that the roots can take up water and the leaves can give out water.  Perfect illustration of the same principle with reversed applications. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 22/06/2009 11:25:26
Quote
The arguments for accepted explanations for fluid transport in trees has not been forthcoming, in fact this thread has shown they are indeed flawed.
AKF. Why are you resurrecting this?

So your argument is not flawed?
As a matter of fact, you have no scientific argument at all. You keep repeating purple passages and the quoting the same instances. Is there any new development in research since you last posted?
We established that, in your smooth tube, you could get a measurable effect from cohesion in water which was a surprise to me. I have accepted that it happened. But is does not explain where the energy comes from.

 Your explanation ignores the rest of Science on the grounds that you are ignored due to lack of qualifications.  The reason that I / we don't accept your explanation for the phenomenon is because it is not a scientific one. You are  hanging it all on the idea of cohesion vs adhesion. However, the Science which applies everywhere else in the World is not allowed to act inside plants - according to you. Isn't Science supposed to be consistent?

Whilst we are 'imagining', lets discuss your circulatory model and use a simple mechanical model.
Take a long loop of rope hanging over a pulley at the top of a building. Tie buckets at regular intervals onto the rope.  Fill each bucket with water and add some stones. The stones represent your dissolved salts.
The buckets are spaced equally on the rope, for a start. (This is a simple model, so you have to ignore the problem of getting the buckets over the pulley at the top if the rope moves around - but that could be solved, of course.)

As an analogy to your transport theory, some water and some of the rock leaves the topmost bucket - leaving it half full and with most of the rock in it. It is now lighter than all the other buckets. Manually pull one side of the rope down and half empty the next bucket and the next and the next, as they reach the top and go over. There is now an imbalance. One side of the rope has less load than the other which, left to itself, will pull the emptier buckets back up to the top and those full of water will fall back down. You won't get a circulation.
The only way that you can sustain the motion is for someone at the top to be putting more rocks into the buckets that you want to go down. To lift water constantly, you need fractionally more weight to be added on the other side - constantly.
In a plant, the only source of extra weight, up there with the leaves,  is C from the CO2  from the air (during photosynthesis).  Just do the sums - compare the mass of water lost during transpiration with the mass of food produced by photosynthesis. There are just not enough 'extra rocks' produced at the top to pull the required amount of water up in the buckets. As I have so often said -The Numbers Count!
I have avoided using the Energy word because you have ignored its use in the past. The above, very mechanical, model shows that your proposed system cannot work. Can you possibly have an argument against what I have written?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 22/06/2009 20:19:39
Quote
Your explanation ignores the rest of Science on the grounds that you are ignored due to lack of qualifications.  The reason that I / we don't accept your explanation for the phenomenon is because it is not a scientific one. You are  hanging it all on the idea of cohesion vs adhesion. However, the Science which applies everywhere else in the World is not allowed to act inside plants - according to you. Isn't Science supposed to be consistent?

Not hanging it on the idea of cohesion versus adhesion, this argument was for the tubular experiments, which of course applies to the density flow theory also. Science is supposed to be consistent but it clearly is not when there are errors in the science!


Quote
Whilst we are 'imagining', lets discuss your circulatory model and use a simple mechanical model.
Take a long loop of rope hanging over a pulley at the top of a building. Tie buckets at regular intervals onto the rope.  Fill each bucket with water and add some stones. The stones represent your dissolved salts.
The buckets are spaced equally on the rope, for a start. (This is a simple model, so you have to ignore the problem of getting the buckets over the pulley at the top if the rope moves around - but that could be solved, of course.)

You appear to be missing a huge chunk of information in your analogy. Let me try to clear it up for you.

Picture a 3 mil bore tube (for instance) as one ascending limb, in this case representing the phloem, which is predominantly downward flowing sap and has far more dissolved solutes in it than the predominantly ascending sap in the xylem vessels. (published science).

Now back to the tubular experiment which admittedly is a simplified model designed only to show the density flow and that cohesion and adhesion play a part in the experiment, although I suspect not an equal part, but let’s ignore this for now.

In our ascending tube we use say 6.5mm bore tubing and do not include any salt for the moment. We raise our unequal bore tube up to say 24 meters and we do not see a flow in either direction but a stagnation of water suspended inside both the 3 mil bore tube and the 6.5 mil bore tube. In fact we could probably show 2 tubes attached to one side and a single tube attached to the other side providing there is a smooth uninterrupted bore at the upper most part of the suspended tube. All ends are open to the atmosphere but suspended in a bottle or bottles filled with water and at equal levels with the ground.

Now, let us see how this fits with your rope and bucket analogy. Ok let’s ignore the buckets and rocks for now. If we had a rope that was the same diameter and the same molecular weight, the rope with careful positioning could indeed stay suspended as there would be an equal counterbalance.

But let’s add a rope twice the size and twice the weight on one side of the pulley. Of course we would see one side pulled down by gravity and the lighter rope side drawn up without any added weights.

In the experiment and inside the tree or plant, there is an equalizing fluid balance that takes away the need for raising the fluids or indeed suspending the fluids.

Unlike the simplified experiment the tree has a multi conduited system inside a larger conduit, the bark with its roots beneath the soil. This is important in this instance because like the bottles of water, it offers support for the columns due to the air soil and water pressure applied to the outside of the tree and more so to the roots.

Yet if we cut the roots off or indeed run a chainsaw through the multiconduited tree system we do not see water oozing out but the water inside retracts up the severed trunk, and this also happens when the ends of the tubes are pulled from the bottles while the water is suspended inside the inverted U tube.

Now back to the flow and return system. According to the above explanation and indeed observations, we can have several upward flowing xylem vessels that are counterbalanced by a ingle downward flowing phloem vessel (for arguments sake) This would give us a mechanism for shedding a huge volume of water at the leaves while returning a smaller yet denser volume down the phloem vessel. Again this experiment was conducted albeit a scaled down version of the Brixham Experiment. “ x ascending salt free and one descending tube attached at the centre which was raised to 2.5 metres. Result was that the flow and return continued to work regardless of the weight on either side of the inverted U tube.

The extra molecular weight at the leaf is not entirely relying on CO2. For example, a deciduous tree that has shed it’s leaves cannot rely on CO2 but somehow manages to circulate fluids to the emerging buds.

You have overlooked the nutrients and colloids from the soil, these are delivered to the leaves in dilute solution and MUST be concentrated by evaporation!  Sugars are produced at the leaf from CO2 but cannot be produced if there are no leaves!

Inside the deciduous tree that has shed it’s leaves we have suspended sugars and salts, most of which migrate to the roots during the fall again verifying the need for gravity in any theory that addresses the ascent of sap in tall trees. All that would be required for circulation to continue is an unequal density in the sap and the warmth during the spring and summer provides an external heat / density change to the sap, sufficient to trigger an increase in circulation, but also an increase in positive pressure at the branches, providing the impetus for buds to emerge.

Yes I do have an argument, not against your work an motion analogy but against how you have applied it to a fluid based system.

Andrew

P.S. Yes there has been a huge development recently with regards to publication. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 22/06/2009 23:09:20
So a few lines of total logic are answered with far too much verbiage to even read, let alone answer.
You have not answered the overwhelming fact that, somewhere, you have to produce an equal WEIGHT of falling water plus stuff  (plus a little bit) to balance the amount of water you need to raise.  (You would not argue against the idea of vast amounts of water being transpired, I presume) Whether you are discussing 20m or 1cm. Where do all these extra weights - ropes, salts etc. come from way up there in the tree? If you want to pull something up you need something to pull it down with. If you want the process to continue, according to your model, you keep needing extra weight added at the top.  Where could it possibly come from? This is not Science - it's what a child with a construction kit would conclude. It could not work on that principle.
Can  you really not understand that?

I wonder why I bother, sometimes.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/06/2009 00:06:33
Try the Bleep experiments before you jump to conclusions!

Listen to what has been said!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 23/06/2009 05:50:47
Hi Andrew.  I'm not in the habit of agreeing with Sophiecentaur - but I must here make an exception.  He's drawn an analogy to buckets and stones?  Where is your answer?  Altenate science is absolutely the very best of all things.  In principle I am full blown, heart felt, initiate.  But I draw the line when alternate science also becomes illogical. 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 23/06/2009 07:49:25
We frequently find that alternate Science theories just change direction to suit rather than dealing with inconsistencies. If a molecule interacts chemically or mechanically with its neighbours in a particuar way under one set of circumstances then, unless conditions are radically changed, we normally expect it to behave the same way in another set.
Just how the molecules are supposed to know they're in a tree and not in a tube beats me. Unless it's supposed to be the 'flow' that sustains the flow - being perpetual motion.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/06/2009 12:05:46
Water is inside the tree during growth and the tree does not have to lift water to it's leaves because it is already at the leaf and if it is not then the leaf is desiccated and dies! No need to explain how a dead tree can suddenly decide it wants to pull water from the ground because it does not happen in nature. “Having said that I remember a Yucca Plant that died below completely yet somehow sent down a taproot through the dead trunk and began growing again.”

So if the fluids are suspended from ground level, all we need to show is how these fluids circulate by introducing a density pumping mechanism.

Here we have a density change caused by evaporation , which no one can argue against!

As molecules of denser solution are acted upon by gravity they have to migrate down the tree from a source to a sink and in doing so drag on all of the other sap molecules inducing not only a downward flow but a return flow. “for every action there is a reaction” The downward flow “source to sink” in a tree is located in the phloem. The sap in the phloem contains more dissolved solutes and is denser than the upward flowing xylem sap. If you can for a minute picture the beads of phloem sap as links in a chain around the branches and trunk of a tree it is not difficult to see how phloem in some parts of the tree can move against gravity as it is dragged around the circuit by the downward flowing denser sap.

We don’t need to show buckets with stones in them and rope as an analogy, it simply does not fit with the fluid model because the fluid model adapts to suit the different diameters of tubular cells within a tree.
I have mentioned before that the density changes in the ocean caused by evaporation and heat drive the Altlantic Conveyor System, an underwater river bigger than all the rivers in the World put together. In the ocean there are no vessels or tubular cells to obscure the density bulk flow.

In a domestic pump-less hot water system we can see a flow and return “copper pipes” This appears to behave the same as the ocean and does not rely on nylon as a material as you suggested earlier.

INDEED WHY WOULD WE EXPECT THE SAP IN A TREE TO BEHAVE DIFFERENTLY?

Your rope analogy cannot adapt or alter it’s shape, it is after all a solid, so for example as it passes over the pulley it would have to become thinner having shed some rope to the atmosphere and as you rightly state would counterbalance any added density. “your rocks in a bucket”.

When density changes in sap, it exerts a dragging effect on the molecules while at the same time exerts a positive pressure on the molecules in front of it. This positive pressure forces the more dilute xylem sap to move upwards above the original level adding the impetus for the tree to continue to grow vertically. It also explains as I have said before how sap exudes from a cut stem, nothing to do with root pressure but to do again with density changes in the sap!

Here is another analogy. Instead of rope we use stretchy slime. The slime can evaporate water to the atmosphere and become denser. The denser slime bulges as dissolved salts apply positive pressure to the slime causing it to visibly swell, (observed using latex soft walled tubing) and the upward flowing stretchy slime can be drawn up from a reservoir of slime under tension applied by the downward flowing slime causing it to become thinner (again observed in soft walled tubing). But the tree has the equivalent of a fluid filled support stocking “The Bark” that not only prevents the sap from bulging but prevents the internal cells from changing shape-due to the pressures applied internally. Very much like the pressure we apply to varicose veins and oedema using the stockings.

Trees grow and die perpetually or am I mistaken?


We frequently find that alternate Science theories just change direction to suit rather than dealing with inconsistencies. If a molecule interacts chemically or mechanically with its neighbours in a particuar way under one set of circumstances then, unless conditions are radically changed, we normally expect it to behave the same way in another set.
Just how the molecules are supposed to know they're in a tree and not in a tube beats me. Unless it's supposed to be the 'flow' that sustains the flow - being perpetual motion.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/06/2009 13:18:23
Witsend. Page one of this thread contains a reference to our understanding of osmosis by the now late professor H.T.Hammel, Emeritus Professor of the Max Plank Institute and a life,s work into the ascent of sap in tall trees, many published papers and he was definately not convinced by osmosis explaining everything or indeed anything in it's curent format.

Logic must also apply to the curent explanations for the ascent of sap in tall trees, but alas is clearly lacking in logic. For example: the evaporation of water from the leaves cannot suck / drag / move / pull / call it what you like on a column of water in a tall tree! We cannot suck water up more than 10 meters in an open ended tube, many people have tried over the years and failed so why should a tree have different rules? 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 23/06/2009 17:25:08
Ok Andrew K Fletcher - I take it back.  That was really well explained.  It's more or less what I understood as the action of osmosis.  Just couldn't think that it could be improved on or even that it should be questioned.

Clearly there's some nicety that eludes me.

Thanks for the explanation.  I now need to understand why Sophiecentaur objects.  It's possibly because you aren't qualified?  That's why he won't answer my questions.  Just tells me to get an eduction.  I think we've been joined in the same bracket. 

Incidentally I love your quote that you include in every post.  I can't get an experiment replicated - and I know a little about that contempt.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 23/06/2009 18:05:52
Unless it's supposed to be the 'flow' that sustains the flow - being perpetual motion.  Sophiecentaur

I think the point is that the sap from the phloem is not the same as the sap from the xylum.  The actual sap is different, therefore their molecules are also different. 

Here's my take, for what it's worth.  The trees' roots are only able to take water in.  They do not transpire. So once in it never comes out.  That's simple osmosis.  I remember it was described as a valve action that closed as the cells became turgid.  So it's a one way action.  The water is transported from the roots to the the xylum and then up the tree trunk in a sponge action.  That precludes a pump action and the question then is how far is the reasonable for water to reach from a sucking rather than a pump action?  I know damp rises. 

It then reaches the leaves where it is taken into the leaf cells through that same osmotic action.  There it is changed into sugar through the miracle of photosynthesis which then is ready to be transferred to various parts of the tree for it's general well-being.  Then, having been manufactured the same sugary sap is fed back to the phloem cells in the stem of the leaves - as opposed to the xylum cells at its centre.  Excess water is transpired from the leaves as a waste product of photosynthesis, together with oxygen, and the cells, through osmosis take in more water from the xylum cells to replace that lost in transpiration- and on and on.  The action is, indeed, perpetual.  But only in the same way as our own digestive system is pretty well perpetual.   But I'm not sure that it needs anything more complicated than the xylum's ability to hold water - much as a sponge would hold water. 

If I've missed the point - apologies.

     
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 24/06/2009 21:53:27
AKF
You do not seem to understand so much of the Science I quote to you that really cannot rely on your having understood what you have read of H.T.Hammel's work either. Do you have a reference which I can access easily and make my own assessment of what he actually says, please?
If you deny the relevance of Energy in all this, then you are onto a loser if you want a valid theory. Leaves, at the top of a tree, were produced with materials, including water, that had to be carried up there from the ground. If that didn't require energy to raise the stuff in the first place then we have to seriously reconsider the whole of our understanding of everything. Energy is needed to lift the water for transpiration - where does it come from? (Using the accepted definition of energy please)

Your ideas could only be considered if you were to do a complete energy budget, in which you say how much energy is put in, where it comes from and how much is got out.
It needs more than just verbal arm waving. The shape and width of your tubes has no effect on the gravitational potential energy involved in lifting the water. You have, clearly not seen the ultimate relevance of my simplified rope model - the rope cannot evaporate - it is the water in the buckets that evaporates. The rope is the intermolecular attraction, if you like.
As I commented earlier. You just shift your ground rather than dealing with my specific objections. Is that true Science?

Spelling edit
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/06/2009 11:42:13
Evolving ideas about osmosis and capillary fluid
exchange1
H. T. HAMMEL
Department of Physiology and Biophysics, Medical Sciences Program, Indiana University School of
Medicine, Bloomington, Indiana 47405-4401, USA

http://www.fasebj.org/cgi/reprint/13/2/213

Energy is from the sun, evaporative energy from the atmosphere and gravitational force / energy from the planet. Simple enough?

Where is the energy that drives osmosis? Where is the energy that mystically sucks water from the ground to a hundred metres through the leaves in the Cohesion Tension Theory? Where is the energy that enables trees to soak up say 500 litres of water per day and allow it to flow out of the leaves? Where is the energy that mystically applies root pressure and squeezes water out of the leaves. Where is the energy that enables water to attract water to the canopy of a giant Californian Redwood?

Quote
Your ideas could only be considered if you were to do a complete energy budget, in which you say how much energy is put in, where it comes from and how much is got out.
It needs more than just verbal arm waving. The shape and width of your tubes has no effect on the gravitational potential energy involved in lifting the water. You have, clearly not seen the ultimate relevance of my simplified rope model - the rope cannot evaporate - it is the water in the buckets that evaporates. The rope is the intermolecular attraction, if you like.
As I commented earlier. You just shift your ground rather than dealing with my specific objections. Is that true Science?

It is your rope model that is in need of revision because it does not address experimental observations. The video on Youtube showing water flowing around a vertically suspended inverted u tube between to ground level vessels speaks volumes about the differences between your rope analogies.

For example picture your rope inside the 24 metre suspended tube, give it a tug on one side and watch it gather momentum as more and more weight is shifted to one side, the rope is pulled up on one side and falls down the other side.

Now picture two identical levels of water in 2 bottles with both open ends of the inverted 24 metre high tube placed at ground level inside the bottles, secured with wire. Initiate the flow by adding say 2 grams of salt to one side. Now we see a downward flow that is dragging on all of the water molecules pulling them in the direction of the falling solute and pushing the water molecules in front of the falling salt solution. But at ground level we see water displaced in one vessel and water level in the other bottle falling on the upward flowing side. Clearly there is an energy imbalance here because the level dropping does not reflect the amount of solute added.

I state exactly what was observed experimentally, you keep saying I change direction. I would defy anyone to replicate my experiments and produce a different result.

But the shape and width would clearly have an affect on your rope and bucket model and this is my point! You can’t have one rope on one side heavier than on the other side as it would cause it to rotate and fall to the ground.

The vessels inside a tree are not perfectly uniformed and do not balance upward with outward flow in either number or size yet it does not appear to affect the stability.



Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 25/06/2009 13:40:05
Andrew: I still haven't seen you do the maths with regard how energy is conserved in your proposed sytstem - I imagine you must have done it (it's a five minute calculation) -  how much water (what mass of water) you would expect to draw to the top and leave there compared to the mass of the solution going down, if (as I think you believe) it is only gravity acting on the "down" arm that drives the raising of water to the top of the tree?
If you're planning to disprove the idea of the conservation of energy with your theory, it's as well to be explicit about it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 25/06/2009 14:03:36
Rosy - I think your question has been addressed in something I have written during your post. The idea is that solar energy provides the energy for evaporation and a resulting difference in density produces some flow. The actual amounts involved are, as you say, not specified.
AKF
I am in the middle of reading that article - thanks, it is very interesting and, not surprisingly, is coherent, does not rely on hyperbole or words like "mystically" and has a lot of well related ideas.
I notice that he constantly refers to constraints imposed by energy and thermodynamic principles. He seems to account for every occurrence in a reasoned way. This is no surprise as he has academic discipline. I haven't yet seen where his ideas explicitly support what you are saying.

Returning to the ancient thread of the 'circulating' water tube. The water circulates when you add salt at a height because the hydrostatic pressure is increased and the flow just takes place because of an impressed force. You supplied energy for this movement by getting on some steps and carrying the salt solution up there.  The energy turns up as gravitational potential energy in the difference in levels in your two bottom reservoirs. I can see no reason why the final difference in levels would be affected by where you put the salt. All that would count, in the end, would be the mass of salt you put into the tube and the resulting density change.  You keep implying that it is the flow that makes things happen. It is, in fact, things that cause the flow. Once you stop adding salt, the flow will slow down and stop - when the pressures due to the total weights on each side  balance the difference in hydrostatic pressure in the reservoirs. There is no suggestion, surely, that the process, once started, will carry on for ever. You could, in fact, achieve the same effect by introducing a stream of very small bubbles or a light oil into the up leg of the tubes. (Yes, I know that cavitation could be a problem but not in a short tube).
You say that the energy represented by the level difference does not correspond to the amount of salt added. You would need to justify that statement. To verify this you could use a U tube (not inverted), carefully add your solution to one side and measure the resulting height change (a long  cotton wool plug would help avoid mixing of the water / solutions on each side. Otherwise, you could, of course, measure the density of your salt solution and do the conventional calculation. I have no idea of the amount of salt you used so I can't help you there.
Actually, your experiment does not show circulation- it shows transfer. If both ends were in the same reservoir, the circulation would only carry on whilst you were adding salt - the average concentration of the bulk would just keep increasing.

I am beginning to see what you may be getting at when you say what is going on at the top of the tree. You seem to be saying that the extraction of water at the top (as the solar energy causes evaporation) is increasing the density of the solution, which would provide a pressure imbalance and start a flow. The problem is that the difference in density is small and would require a large downward flow. Then, at the bottom, the plant would need to be disposing of this more dense liquid somewhere away from where it is picking up its fresh water. Without that, the inlet water would start to consist of more and more dissolved salts and the process would self limit. You would need to justify with actual figures (as always).

You may be able to model the system (for a short tube full of salt solution)  by having a window near the top, on one side, with a semi permeable membrane - even some Gortex, which would let water evaporate and produce your concentration effect. The problem is that the construction of the membrane would have to be such that it let water molecules out but didn't let molecules of O and N in. The membranes in plants would have to be able to achieve this and may have to be smarter than you can get with non organic materials.

But, having accepted that something is going on, I can't see the relevance of the 'flow' idea of yours. The energy clearly comes from sunlight causing evaporation and by tension in the water column. What does the flow do for you - whilst it is essential for distributing food and oxygen around the plant, why do you want it to be part of the 'driving mechanism'?

BTW, are you still insisting that the circulation in our bodies is not actually driven by the heart? That's what you seemed to be saying in one of your other posts, some while ago.

Are you aware of the concept of Negative Potential Energy. That is what gravitational energy  is. You can only 'get' energy from gravity by raising something above its rest position. That involves an energy input (positive). Gravity is no different from a spring, in that regard. Your first statement doesn't make sense, I'm afraid.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/06/2009 18:08:38

1.   Irrigation in arid conditions leaves behind a crust of salt due to the high evaporation rates. This is what started my journey. Where trees were present in the arid areas, the crust of salt did not contaminate the land sufficiently to kill the trees given that these trees were well established and thriving.
2.   The same saline contamination must also apply to vegetation, trees included, as they evaporate water effectively so one would expect a build up of salts at the leaf and we should see salted crowns on trees everywhere but normally we do not. Except for mangrove and a few others, but even these are not overly contaminated at the leaf.
3.   Due to the effects of gravity on solutes, We should see salt and sugars accumulating at the roots and normally they do not except for a deciduous tree shedding it’s leaves, then we see a build up at the roots over the winter.
4.   If the salts under normal active transpiration and circulation are not found at the roots, then there is a storage mechanism in the timber and no one can dispute that trees are very good at storing carbons and salts, in fact a paper I read a long time ago said trees were used to take up highly toxic heavy metals and lock them safely into the timber. But the dilute water arriving at the roots would suffice to re-dilute salts and sugars enabling the tree to actively transport them back to the leaf providing the upward flow is always more dilute than the downward flow and this appears to fit with the literature.
5.   You mention the U tube experiment showing differences in levels. No cotton wool is required to keep the solutes from mixing with the solute free side. I have observed a suspended Youtube preventing diffusion for several weeks by using food colouring to monitor this. Will conduct the experiment again if you like and photograph it every day or you could try it and see for yourself. This presents more problems for the literature because diffusion is thought to be an influential driving force also.
6.   Adding a gortex window is an interesting idea, however it would not work with the 24 meter experiment because the gortex would provide a cavitation seed point, unless the experiment was inside a water filled tube to support the water columns. “this reflects the trees structure more than the simplified  Brixham experiment”
7.   Gravity energy potential. Evaporation from the oceans provides rainfall that causes rivers to flow. No one has to lift anything anywhere it just happens every single day of the year. Evaporation from the ocean surface is all that is required to drive the Worlds ocean currents, an underwater river bigger and more powerful than all of the rivers in the world put together. So why are you trying to avoid the connection with density flow trees and plants?
8.   Picture one salt laden molecule attached to all of the other water molecules in the tube experiment. How does it move away from the other molecules without affecting their motion? It can’t! If cavitation occurred the salty water molecule would apply a positive compressing force on all of the other water molecules “the butterfly effect in fluids”
9.   The Heart inside a chickens egg does not beat at conception, How could it, the heart does not develop before the circulation is in place. Primary circulation is established long before the primary tubular structure of the heart develops. The egg need to be rotated and as it is egg shaped it can only be rotated across one axis under normal incubation, so why does the egg need to be rotated at all? Could the migration of salts through the albumen be initiating this primary circulation? If the heart was entirely responsible for circulation, which it clearly is not, then varicose veins should worsen when the head of the bed is raised by 15cm’s. After all, the medical establishment promote this idea by advising patients to sleep with the head of the bed lower, or raise the legs higher, yet it does not have any lasting effect on varicosity. So one would expect the medical establishment to re-think their logic and question their own misguided non-scientific belief system. Yet they continue to advise raising the legs knowing full well that it will be of no use long term and surgery will be required eventually. So there is something clearly wrong with the literature. Professor Hammel sent me a paper. Hammel said during a telephone conversation that he had observed a pulsate solute flow arriving at the kidneys and was very excited by the simplicity of the evaporative density flow.

Roles of colloidal molecules in Starling's hypothesis and in returning interstitial fluid to the vasa recta
H. T. Hammel
Department of Physiology and Biophysics, Indiana University, Bloomington 47405, USA.
To begin to understand the role of colloidal molecules, a simple question requires an answer: How do the solutes alter water in an aqueous solution? Hulett's answer deserves attention, namely, the water in the solution at temperature and external pressure applied to solution (T,pe1) is altered in the same way that pure water is altered by reducing the pressure applied to it by the osmotic pressure of the water at a free surface of the solution. It is nonsense to relate the lower chemical potential of water in a solution to a lower fugacity or to a lower activity of the water in the solution, since these terms have no physical meaning. It is also incorrect to attribute the lower chemical potential of the water to a lower concentration of water in the solution. Both claims are derived from the teachings of G. N. Lewis and are erroneous. Textbook accounts of the flux of fluid to and from capillaries in the kidney and other tissues are inadequate, if not in error, as they are based on these bogus claims. An understanding of the process by which colloidal proteins in plasma affect the flux of nearly protein-free fluid across the capillary endothelium must start with insights derived from the teachings of G. Hulett and H. Dixon. The main points are 1) colloidal molecules can exert a pressure against a membrane that reflects them and, thereby, displace a distensible membrane; 2) they can alter the internal tension of the fluid through which they diffuse when there is a concentration gradient of the molecules; and 3) only by these means can they influence the flux of plasma fluid across the capillary endothelium. However, the process is complex, since both the hydrostatic pressure and protein concentrations of fluids inside and outside the capillary vary with both position and time as plasma flows through the capillary.




 
Effect of a Salt Crust on Evaporation from a Bare Saline Soil
Haruyuki Fujimakia,*, Takahiro Shimanoa, Mitsuhiro Inoueb and Kazurou Nakanec
http://vzj.geoscienceworld.org/cgi/content/abstract/5/4/1246

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 25/06/2009 19:19:10
A couple of comments- you have replied with overkill, as usual and I am overwhelmed.
Point 7. NoBODY carries the water up there into the clouds- the sun provides the energy for the latent heat of vaporisation. Isn't the water cycle taught in School?
Point 6. Of course a gortex window wouldn't work on a high tube. I said so. You wouldn't need to climb your cliff to test the idea. I doubt that the goretex would be impervious to air molecules for anything other than a few cms of head, unfortunately.
Point 9. Small animals do not need hearts because the chemical gradients are enough to get nutrients around by diffusion. Insects  do not use a blood system for respiration either. You are so obviously convinced about the success of your treatment of varicose veins that you seem unable to consider that the explanation is anything other than your home-brewed one. Again, they are two separate issues. In mediaeval times, doctors often used to manage to make people well despite working on the Galen model for medicine.
Point 5. The difference in level will directly depend upon the difference in densities.How can it do anything else?

Points 1,2,3,4 Yes, of course salts move around in a plant but you are proposing that the salts have to move in order to make the flow happen. That is an entirely different matter.
Point 8. What is a "salt laden molecule"? afaik, salt exists as ions when in solution. What is laden with it?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 25/06/2009 21:00:45
Andrew, your embryo argument has been refuted by several of us already. Please be less like a creationist and stop using it - how stupid do you think we are?

http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216255#msg216255
http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216702#msg216702
http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216712#msg216712

More generally, it would be nice if you either become more sensible or stop arguing about physics and medicine altogether.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 25/06/2009 23:33:23
Andrew, the point here is that Sophiecentaur does to original thought is what rain does to fire and dampness does to squids.  I'm beginning to get an obsessive interest in the personality type.  But I would strongly recommend that you don't try and reason with him unless you actually quote from a text book.  He has a certain stiffness.  A want of flexibility.  Struggles a little with the abstract thought.  And he trawls through the new ideas threads because he's determined to kill any such, at birth.

He's also a scientist who makes up his mind about an experimental results without doing the experiment.  Rather a contradiction in terms. So don't get discouraged.  Then he'd have achieved his object.  He's not interested in the idea.  He's only determined to put you down.   



 
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 25/06/2009 23:38:41
witsend
I guess you would say the same about anyone who had their feet on the ground.
I have built your circuit many times. It's a relay driver. They work conventionally.

I should listen to your friends. If they wonder why you posted your idea on a forum then perhaps so should you.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 26/06/2009 00:39:44
I have built your circuit many times. It's a relay driver. They work conventionally.Sophiecentaur

Yet another example of a total misconception of the experiment and its intention.  It is NOT a relay driver.

And I joined this forum because its the best fun I've had since Christmas.  There are not that many people who give up their time to 'talk physics'.  I spend a fortune on phonecalls to various friends from all over the world just to indulge this passion.  My own circle of family and friends don't have a clue what I'm on about and quite frankly it's lonely.  This fills that gap. I just wish I could get past the personality and get back to physics.  If you were less destructive you'd be ideal.  But you're on a mission.  I think you're trying to protect the purity of physics from fraudulent misreprestations.  You haven't the ability to tell fraud from a left foot.  And I'm no fraud.     
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/06/2009 08:08:37
You make your point very clear Stefan, transparent actually and not a point of view I am unfamiliar with, coming from predominantly people who prefer the literature to remain un-tested.
Labelling me as a creationist says you have not bothered to read what I have written, else you would see that I have no religious interests and do not dwell in a belief system. You do yourself a disservice and add nothing to this discussion with your sneers.


 
Andrew, your embryo argument has been refuted by several of us already. Please be less like a creationist and stop using it - how stupid do you think we are?

http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216255#msg216255
http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216702#msg216702
http://www.thenakedscientists.com/forum/index.php?topic=18961.msg216712#msg216712

More generally, it would be nice if you either become more sensible or stop arguing about physics and medicine altogether.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 26/06/2009 09:02:04
You are like a creationist in that you keep using dead arguments and don't listen to reason.

Do you think your nonsense is a valuable contribution?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 26/06/2009 11:41:01
Andrew, the point here is that Sophiecentaur does to original thought is what rain does to fire and dampness does to squids.  I'm beginning to get an obsessive interest in the personality type.  But I would strongly recommend that you don't try and reason with him unless you actually quote from a text book.  He has a certain stiffness.  A want of flexibility.  Struggles a little with the abstract thought.  And he trawls through the new ideas threads because he's determined to kill any such, at birth.

He's also a scientist who makes up his mind about an experimental results without doing the experiment.  Rather a contradiction in terms. So don't get discouraged.  Then he'd have achieved his object.  He's not interested in the idea.  He's only determined to put you down.   

I disagree entirely.  Sophiecentaur would, no doubt, be thrilled to see established science proven wrong and updated - but only provided it is on solid enough evidence and theory.  If he's pushing you at all, it's to make your science better, not to destroy it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 26/06/2009 12:40:20
AKF
Quote
Labelling me as a creationist says you have not bothered to read what I have written,
You shot yourself in the foot there, I'm afraid.
If you "had read" what was written, you would have seen that stefan said that you were "like a creationist" and not"a creationist".
I'm afraid that you see what you want to see and make what you want to out of what you observe and what you read. A bit more discipline might help to improve your grasp of Science and allow you to make valid conclusions.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/06/2009 13:11:45
You are like a creationist in that you keep using dead arguments and don't listen to reason.

Do you think your nonsense is a valuable contribution?
Much better argument than the arguments relied upon in the literature!

Repeat: Osmosis does not account for the fluid transport volumes observed in tall trees. Root pressure is a joke. Cohesion tension theory sucks and capillary action cannot account for the size of tubular dead cells found in the xylem of tall trees. And let's not forget Strasburger's experiments that rulled out any living processes actively involved in bulk flow.

You are defending erroneous literature!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 26/06/2009 13:21:32
Hi BenV.  Always delighted to see your input.  It continually amazes me that you actually follow these threads.  I'm sure you know the analogy of the wind and the sun.  They took a bet as to who could encourage man to take off his coat.  Wind tried to blow it off and failed.  Sun achieved his object with relative ease.

There's a wild lack of constructive input and an entire want of good manners.  Points are taken in isolation and the overview is so wanting that it becomes positively absurd. He enjoys this liberal barrage of insult at the cost of my intellectual respect.  But I grant you, I possibly parade that lack too freely.  However, in my defense, when I draw breath and try again, I am simply again reminded of his aptitudes - or his lack of them.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/06/2009 13:22:44
Sophie, I really appreciate your guidance and for showing me how this needs to be presented.

I have an offer of much needed help with presenting a paper for publication from a retired doctor and engineer.

Ben you are Bang to right on Sophie's intentions. Ok we have had a few disagreements and occasionally a few terse comments, but generally most helpful and shows my failings of oversimplifying while trying to present my observations.

Witsend, you will find that the responses you receive will be more favourable if you refrain from attacking the person rather than the subject at hand. Yes it can be frustrating to try to explain a new direction in a way that it has clarity for all concerned, but at least we can learn how what we write is interpreted by others and this makes for a stronger argument in the end.

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 26/06/2009 13:29:24
Witsend, you will find that the responses you receive will be more favourable if you refrain from attacking the person rather than the subject at hand. Yes it can be frustrating to try to explain a new direction in a way that it has clarity for all concerned, but at least we can learn how what we write is interpreted by others and this makes for a stronger argument in the end. Andrew K Fletcher


Andrew, I am entirely satisfied with the responses I get in this forum - with the entire exception of Sophiecentaur's.  But I'm glad he seems to serve you as a guide to lighten the light - so to speak.  Me, I find his input obnoxious and counter productive.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 26/06/2009 13:50:47
Put aside your other arguments (which pale in comparison to sophiecentaur's and others' criticisms) for a moment.

You used the embryo argument in a different thread and we demolished it. Yet you repeated it to us in this thread. Do you think we are idiots? Try having some intellectual integrity, Andrew.

You are like a creationist in that you keep using dead arguments and don't listen to reason.

Do you think your nonsense is a valuable contribution?
Much better argument than the arguments relied upon in the literature!

Repeat: Osmosis does not account for the fluid transport volumes observed in tall trees. Root pressure is a joke. Cohesion tension theory sucks and capillary action cannot account for the size of tubular dead cells found in the xylem of tall trees. And let's not forget Strasburger's experiments that rulled out any living processes actively involved in bulk flow.

You are defending erroneous literature!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 26/06/2009 16:49:05
Put aside your other arguments (which pale in comparison to sophiecentaur's and others' criticisms) for a moment.

No one demolished the argument  about gravity influencing embryo development Stefan, how could they? NASA and the former USSR space programmes have done ample research and shown that gravity plays a crucial part in embryo development. Do some homework before jumping to conclusions.

But please start a new thread rather than distracting this one.

Quote
You used the embryo argument in a different thread and we demolished it. Yet you repeated it to us in this thread. Do you think we are idiots? Try having some intellectual integrity, Andrew.

You are like a creationist in that you keep using dead arguments and don't listen to reason.

Do you think your nonsense is a valuable contribution?
Much better argument than the arguments relied upon in the literature!

Repeat: Osmosis does not account for the fluid transport volumes observed in tall trees. Root pressure is a joke. Cohesion tension theory sucks and capillary action cannot account for the size of tubular dead cells found in the xylem of tall trees. And let's not forget Strasburger's experiments that rulled out any living processes actively involved in bulk flow.

You are defending erroneous literature!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 26/06/2009 17:17:06
That gravity influences physiology is not the argument. The argument we demolished is that gravity has the effect you think it does.

You brought this up yourself, so it can stay in this thread however inconvenient it may be for your agenda.   

Meanwhile, please start responding more effectively to sophiecentaur's posts. He's been more patient with you than I think you deserve.

No one demolished the argument  about gravity influencing embryo development Stefan, how could they? NASA and the former USSR space programmes have done ample research and shown that gravity plays a crucial part in embryo development. Do some homework before jumping to conclusions.

But please start a new thread rather than distracting this one.

Put aside your other arguments (which pale in comparison to sophiecentaur's and others' criticisms) for a moment.

You used the embryo argument in a different thread and we demolished it. Yet you repeated it to us in this thread. Do you think we are idiots? Try having some intellectual integrity, Andrew.

You are like a creationist in that you keep using dead arguments and don't listen to reason.

Do you think your nonsense is a valuable contribution?
Much better argument than the arguments relied upon in the literature!

Repeat: Osmosis does not account for the fluid transport volumes observed in tall trees. Root pressure is a joke. Cohesion tension theory sucks and capillary action cannot account for the size of tubular dead cells found in the xylem of tall trees. And let's not forget Strasburger's experiments that rulled out any living processes actively involved in bulk flow.

You are defending erroneous literature!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 26/06/2009 18:07:30
Andrew K Fletcher,

I assure you that if you EVER email me again with such fatuous comments I shall copy that email and paste it on this thread.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 29/06/2009 17:28:50
Do what you want, and welcome to my ignore list.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 29/06/2009 21:28:12
Andrew K Fletcher,

I assure you that if you EVER email me again with such fatuous comments I shall copy that email and paste it on this thread.
Please enlighten the rest of us. It seems that Andrew isn't bothered and I'm sure I'm not the only one who wonders what he said.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: witsend on 29/06/2009 21:45:58
Hi Bored Chemist

It was nothing interesting.  Andrew wrongly assumed that I shared his opinion about certain things.  I must assume it was emailed because he wanted that opinion kept confidential.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 29/06/2009 23:02:16
I don't think PMs are appropriate for these sorts of interchanges. Keep it public.
When Lawyers start  to communicate out of court, someone has realised they're on dodgy ground .
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 01/07/2009 09:20:41
Question for B.C. et al.

If a tree is suspended vertically in a bath of picric acid has it's roots severed as was the case with Strasburger's experiment showing circulation continued for weeks following the event, despite the tree being completely killed by the influx of acid. What would this acid do to the semi-permiable membranes within the tree? Worth remembering that the leaves were completely killed yet obvious transpiration carried on inside the tree unaffected by this destruction of all living processes.

Andrew
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 01/07/2009 09:43:11
AKF
As usual, you gather a lot of evidence and most of it is sound. You may have revealed a contentious issue - which is interesting. (The reactions you have been getting from other members show that they agree with what I am saying.)
The problem is that you keep trying to impose your own explanation on the phenomenon. If your model doesn't apply elsewhere in Science, then you can't insist that it is valid in this particular case. Science doesn't work in compartments - there must be an explanation which satisfies all conditions - not just in Biological situations - and your model really does not fit the majority of evidence.

Have you never considered that your fundamental view of basic Physics could be flawed? Is it not just possible that conventional Science - which you resent so much - could have got things right about Physics? You seem to want to argue with basic Mechanics in addition to biological phenomena which may be harder to measure and model. Your explanations contain far too much much metaphor and simile and not enough numerical evidence to back them up. Just because you can't imagine why, when you're wrong, proves nothing.

That paper you referred me to says nothing about your particular theory. Did you ever wonder why?

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 06/07/2009 10:01:35
Test the experiments for yourself before jumping to conclusions about how this fits with other systems.

I gave the ocean current "Atlantic Conveyor system as one example with density flow. Another with a domestic hot water pumpless system, another with air density changes relating to hot desert coastlines causing a thermal barrier which prevents the denser moisture laden air from crossing onto the land.

Another with density changes in the blood relating to how dialysis works and indeed how posture alters density in urine.

Far from not fitting it does indeed fit.

Your cuppa in the morning relies on leaves storing salts and sugars. Fruits rely on sugars migrating from a source to a sink.

finger nails and toe nails rely on density changes in order to grow where they grow as do elephant tusks!

Gravity is the key factor in all of this!

How could we work out a density change mathematically in say a cloud passing by, could we explain accurately by how much it's density is affected by heat from the ground, energy from the sun and a cold breeze passing through it? Or would it be more productive to observe the cloud rising or falling?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 06/07/2009 10:40:28
There is nothing at all new about the mechanism of convection, due to thermal density changes or circulation due to the addition of solutes. The forces and the energy involved all account for the values observed. You seem to be  claiming that you have something new here. Why? No one has denied that it happens - the objection is that you seem to have commandeered it as as 'source' of motive energy.

Of course gravity is involved. When you drop a stone on your foot, 'gravity is involved'. Left to itself, however, gravity won't do it again. Someone has to lift the stone again - providing gravitational potential energy - before it can happen again. 'Gravity' is not the source of the energy, any more than a watch spring is the source of energy for a watch.

You have your usual list of observable processes, as if that actually constitutes proof of anything (apart from the fact that they happen).

As for calculations about clouds vs standing watching them - it depends what you want out of the exercise. If you want a chance of predicting what will happen with a cloud under a new set of circumstances then you need to get some understanding of the Physics involved. As you are posting on a Science Forum, I should have thought that would be your interest. The analysis of clouds is not difficult - it's done all the time, along with a lot of other thermodynamic calculations.
If you had no idea of what was going on in a cloud apart from the fact that it was rising or falling, how would it increase the sum total of human knowledge? You would need to study / measure the parameters of that cloud and then do some ACTUAL SUMS (Andrew!!!!) before you would get anywhere at all.
I'm afraid your maths-free approach to your theories is of even less use than alcohol-free Whiskey.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 06/07/2009 12:34:25
Of course it is nothing new. The cloud rises into the atmosphere because of the energy provided by the sun. No one has to lift the clouds into the air but the fact remains many tons of water are lifted into the atmosphere from the ocean and this triggers a density change in the ocean surface water and this triggers circulation. Not rocket science is it? We don't need to work out the exact amount of density change taking place, the fact that it sinks is sufficent.

There is nothing at all new about the mechanism of convection, due to thermal density changes or circulation due to the addition of solutes. The forces and the energy involved all account for the values observed. You seem to be  claiming that you have something new here. Why? No one has denied that it happens - the objection is that you seem to have commandeered it as as 'source' of motive energy.

Of course gravity is involved. When you drop a stone on your foot, 'gravity is involved'. Left to itself, however, gravity won't do it again. Someone has to lift the stone again - providing gravitational potential energy - before it can happen again. 'Gravity' is not the source of the energy, any more than a watch spring is the source of energy for a watch.

You have your usual list of observable processes, as if that actually constitutes proof of anything (apart from the fact that they happen).

As for calculations about clouds vs standing watching them - it depends what you want out of the exercise. If you want a chance of predicting what will happen with a cloud under a new set of circumstances then you need to get some understanding of the Physics involved. As you are posting on a Science Forum, I should have thought that would be your interest. The analysis of clouds is not difficult - it's done all the time, along with a lot of other thermodynamic calculations.
If you had no idea of what was going on in a cloud apart from the fact that it was rising or falling, how would it increase the sum total of human knowledge? You would need to study / measure the parameters of that cloud and then do some ACTUAL SUMS (Andrew!!!!) before you would get anywhere at all.
I'm afraid your maths-free approach to your theories is of even less use than alcohol-free Whiskey.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 06/07/2009 14:36:01
Quote
We don't need to work out the exact amount of density change taking place, the fact that it sinks is sufficent.

No, not correct. The actual forces and energy involved are HIGHLY relevant to cloud and air movement if you want to know whether there will be a storm or a breeze. The actual values of the quantities are relevant throughout the real world and to our lives.
Gravity acts on a fly just as it acts on you but you can't walk on the ceiling like a fly because of the (insignificant to you, it appears) relative differences between electric and gravitational forces involved.

Yes - it is as hard as rocket Science, actually. If you don't consider yourself qualified to hold forth on the viability or otherwise of a rocket engine (will it take off or not, given some masses and power specs?) then you are not qualified to have an opinion about the viability or not of your circulation ideas. How can you  KNOW that the forces involved are due to what you say and not to something else unless you have actually worked out both, in detail?
Nothing "is obvious" when you want to prove an hypothesis.

Just 'like' a creationist, you are ignoring some evidence and repeating, ad nauseam, some other (misinterpreted) evidence. Is that Science?

btw, we have now established that you acknowledge that gravity does not supply the energy for these processes so, perhaps, you will stop telling us that it is the key to the whole thing.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 06/07/2009 16:26:52
btw, did you know, AFK, that the water is not "lifted"into the air. It is displaced upwards by good old Archimedes' principle. Warmer or 'damper' air are both less dense so they are displaced by cooler,  dryer air and 'upthrust' upwards.  The old bollocks statement about warm air rising and cold air rushing in to take its place is ,,,,well,,, bollocks. You can't suck air. Some new theories may suck, though!
Work is done against gravity in' lifting' the cloud. The clouds don't just go up because of the Sun they are actually Pushed up by the surrounding atmosphere.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 11:34:07
When they bury you will they put your qualifications on your head stone? Or have you contributed something significant we can all remember you by? Enlighten us please.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 12:02:11
Andrew - I don't expect to see a comment like that from you again.  If you can't defend the science, do not attack the person.

Maybe you should try to take him on on his own terms?  i.e. using facts and figures to support your argument?

I should warn you, Sophie comes out of this conversation as looking a lot more reasonable than you.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 07/07/2009 14:58:47
Andrew,
Perhaps you would like to answer the same question you asked of sophiecentaur.

What have you actually achieved? I mean real achievemnets rather than hypotheses that are not well supported by evidence, so nothing that isn't going to be written off as a coincidence.
(I'm not, BTW, claiming that my epitaph will be anything special, but since Andrew asked...)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 15:06:28
BC, I understand the retort - it was an offensive and inflammatory thing for Andrew to have said - but I don't feel this line of conversation will benefit the forum.  All it will lead to is hurt feelings and this thread being locked.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 16:07:38
I don't see anything wrong with my comment. It was written to point out that to be remembered it is not enough to cross the T's and dot the I's. Original thinking is what counts!

B.C. I will be remembered for my contribution to understanding circulation in trees and plants, but also for relating the same principles to circulation in animals and humans.

I will also be remembered for my experiments with water filled tubes at Brixham and for applying a great deal of common sense to how correct posture over long periods can beneficially influence the body.

My question still stands. How many gravestones have you found with a list of qualifications etched into them?

Andrew - I don't expect to see a comment like that from you again.  If you can't defend the science, do not attack the person.

Maybe you should try to take him on on his own terms?  i.e. using facts and figures to support your argument?

I should warn you, Sophie comes out of this conversation as looking a lot more reasonable than you.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 16:15:04
Andrew, the problem is not that you do not have certificates to say you can do something, the problem is that you are not qualified because you do not tackle the hard facts of the issue, i.e. the energy calculations etc, in short, the maths.

At present, you may be remembered by people here as finding something interesting, but then sticking arrogantly to a hypothesis that does not add up.  Not a grand achievement.  Wouldn't it be better to be thought of as someone who developed a hypothesis that added to science?  Or someone who took criticism well and thoroughly answered the questions of all his critics, collaborating and working well with people?

Does it not concern you that many people here do not think you are correct?  Even after years?  If you are correct, you should be able to prove it to them, in their language, using a full understanding of the science involved.  You have either chosen not to bother, or you can't do so and refuse to ask for help, or you know that your hypothesis does not stand up to scrutiny.  Which one is it, Andrew?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 16:21:56
The one that it is is not listed there. It is test the experiments for yourself and see for yourselves how a tiny amount of salt can move many times it's own volume around simple tubular experiments.

My critics can't be bothered to repeat these simple experiments and would rather believe that leaves on trees can somehow suck water up to well over a hundred metres vertically. The trees can't do this any more than a powerful pump coud do it, so why do we keep churning out this garbage when it is unsupported? This is what led me to question the literature and quite rightly so!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 16:31:00
So it's everyone else's fault?

They do not have time, enthusiasm or facilities to do your experiments - it is your responsibility to put it in a language that they can understand and either accept or further question.

You've also missed the point again - it's not the results that cause controversy, it's the explanation and extension to plants and animals.

THIS IS YOUR RESPONSIBILITY ANDREW - DO THE REAL SCIENCE AND EITHER YOUR CRITICS, OR YOUR HYPOTHESIS, WILL FALL.  REFUSE TO DO THE REAL SCIENCE AND YOU FAIL YOURSELF AT THE FIRST HURDLE.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 16:41:08
Remember Ben,
I read the GCSE Biology book by D.G. Mackean to find an answer to what trees were doing with salts, approaching the question of fluid transport in plants and trees with an open mind, a mind that vaguely remembered the biology lessons from many years ago “too many years ago”.

None of it made sense to either me or Don Mackean who wrote the book.

This led to the hypothesis about a density flow rather than the pathetic explanations, which incidentally are still adhered to even though no one has demonstrated any working model. The experiments followed after the hypothesis, not to add credence but to test the density flow and to test the 10 meter limit also referred to inside the same text book.

The initial experiments, the ones before the Brixham experiment were attended by a very proficient physicist and dear friend “Adrian Van Sweden” who gave me lot’s of reasons why the experiment would fail and then lot’s of questions about why it did not fail together with sitting on a step with his hands over his eyes shaking his head saying repeatedly “this is not possible” “Why was this never mentioned in the literature?” “Why do I find it so hard to accept?” Adrian also helped with the Brixham Experiments. He was also a former engineer for South West Water and a person who found a great deal of benefit from sleeping inclined, recovering circulation to his feet, toes, hands, fingers, lips, nose which were blue due to a heart defect and metal valve which incidentally could be heard missing beats at night while sleeping flat and should, according to a doctor we met have fibrillation, adding all metal valves have fibrillation, yet Adrian’s didn’t anymore!

Most of my time over the years has been spent helping people to recover from a range of illnesses. I have found it both rewarding and intriguing and far more useful than trying to convince some people who obviously do not want to be convinced of anything outside of the convenient box.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 16:41:31
The experiments came after the hypothesis not the other way around
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 07/07/2009 16:44:42
Ben, given the fact that most schools and colleges have a  budget that could easily afford a bit of plastic tubing, a length of strong string to pull the experiment up, a pinch of salt and a couple of empty bottles, it is hardly a question of resources now is it?

So it's everyone else's fault?

They do not have time, enthusiasm or facilities to do your experiments - it is your responsibility to put it in a language that they can understand and either accept or further question.

You've also missed the point again - it's not the results that cause controversy, it's the explanation and extension to plants and animals.

THIS IS YOUR RESPONSIBILITY ANDREW - DO THE REAL SCIENCE AND EITHER YOUR CRITICS, OR YOUR HYPOTHESIS, WILL FALL.  REFUSE TO DO THE REAL SCIENCE AND YOU FAIL YOURSELF AT THE FIRST HURDLE.


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 16:48:38
I have found it both rewarding and intriguing and far more useful than trying to convince some people who obviously do not want to be convinced of anything outside of the convenient box.

Then what are you doing still here?  If your science is accurate, it's already inside the box.  If you can't be bothered, then why are you still here?

If you are right, you WILL be able to convince everyone here.  If you can't be arsed, then you must accept that people will assume you are wrong - and they are right to do so.

The experiments came after the hypothesis not the other way around

I know, you have said before.  If I hypothesised that there are tiny monkeys in the soil, and they they love my shoes so much that will attract my shoes towards them, I could then do the experiment of moving my shoes away from the soil and seeing in which direction they fall.  My experiment would prove that the soil monkeys love my shoes.

Clearly, I'm being ridiculous.

Only you can explain this and have it accepted.  On this board you have several intelligent people with sceptical attitudes who would be able to help you.  If you answered each and every one of their questions with the relevant data or calculations, you would either find that your hypothesis is flawed, or that their scepticism would pass.

You chose not to do so.  You chose to be offended by their (perfectly understandable) attitude instead.  If this were a game, you lose.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 07/07/2009 16:50:27
Ben, given the fact that most schools and colleges have a  budget that could easily afford a bit of plastic tubing, a length of strong string to pull the experiment up, a pinch of salt and a couple of empty bottles, it is hardly a question of resources now is it?

Andrew, the current explanation may be wrong.  That's fine.  Your explanation may well be correct, but is not strong enough to take it's place.  If you make it strong enough, it will become accepted, and perhaps that is how people will teach this in the future.

You refuse to make it strong enough.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 08/07/2009 10:09:08
Andrew

WE DO NOT QUESTION YOUR PHYSICAL, EXPERIMENTAL RESULTS, SO WHY SHOULD WE ATTEMPT TO REPLICATE THEM?

WE CAN EXPLAIN THEM USING THE CONVENTIONAL THEORY

YOU HAVE NOT SHOWN THAT YOUR NEW THEORY EXPLAINS *ANYTHING* BETTER THAN THE CURRENT ONE

YOU WILL HAVE TO DO SOME ******* MATHS
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 08/07/2009 14:11:52
Re. "B.C. I will be remembered for my contribution to understanding circulation in trees and plants, but also for relating the same principles to circulation in animals and humans."
I wouldn't bet on it.
For example the stuff you posted about the kidney here
http://www.thenakedscientists.com/forum/index.php?topic=17612.0
 is not consistent with observations of the densities of the fluids involved.
The experiments you did show nothing that cannot be explained in terms of the established models of physics and nothing that you have done is backed up by maths or double-blind trials as apropriate.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/07/2009 21:20:06
BC don't make me laugh. Please my ribs are aching as it is. Double blind study? Who is going to do this when it flies in the face of the literature they depend upon so much.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 08/07/2009 22:35:46
BC don't make me laugh. Please my ribs are aching as it is. Double blind study? Who is going to do this when it flies in the face of the literature they depend upon so much.
Don't use this as an excuse for not doing the science you could otherwise do.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 08/07/2009 23:25:18
AKF. You are tilting at windmills here. No one on any of these threads seems to have doubted your experimental results so why should we need to repeat your experiments?  What everyone is disagreeing with is your nonsense explanations. This forum is blind to qualifications and past achievements. You might be surprised to hear what some of us HAVE  actually achieved. We mostly comment on the sense of what we read in these posts. There is no place for inverted technical snobbery. Your claim to being RIGHT just because of your lack of 'qualifications' makes no sense at all.
You quote GCSE level as if that is the sum total of human knowledge. That's plain daft. There are more shortcomings to the School Science curriculum than you've had hot dinners but that is irrelevant to the sense or otherwise of your ideas.
It is also strange that you use the opinions of your own  'expert' to support your ideas but reject the opinions of other experts. That's all a bit selective, isn't it?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 09/07/2009 19:39:30
BC don't make me laugh. Please my ribs are aching as it is. Double blind study? Who is going to do this when it flies in the face of the literature they depend upon so much.
OK, so that's your excuse for not doing bouble blind trials (not a very impressive one but...) .

What's your excuse for totally failing to do the maths?
What's your excuse for persisting with ideas that simply don't hold water when someone else looks at the numbers?


As things stand, if someone took up your ideas and ran with them and they actually turned out to be right then your epitaph might well be "Had some ideas about so-and-so but hadn't the abillity to follow it up with a proper explanation or investigation".
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/07/2009 10:38:33
It's not an excuse it's an observation of over 15 years of observing how people go back on their words and fail for whatever reason they can come up with to carry out this simple repeatable study. Why do you think this is B.C et al? Who stands to gain when this therapy is eventually made mainstream? And make no mistake it will be! But who stands to lose the most money when many drug companies and charities and surgeons and doctors find their services are no longer as important as people currently believe them to be? Do you think for one minute I have not been to Universities, Sleep Therapy Centres, Dr’s Surgeries, Hospitals, Colleges, Secondary Schools, Spinal Units, Members Of parliament, Editors of Journals, Science Forums, Television, Radio, Newspapers, Private meetings with surgeons nurses and doctors, argued and shown exactly how this therapy works in front of professionals in charge of caring for people dying including my own Father?

Make no mistake B.C I know who and what I am up against!

The numbers is not quite as simple as Sophie makes it out to be, and I need some help to make certain that everything is taken into account including all of the observations from the experiments.

For example: A tree grows slowly and is filled with fluids from the onset so does not require fluids to be lifted to the leaves as per Sophies rope and bucket analogy. But does require an understanding of why adhesion and cohesion enables the water to remain inside the tree even when the leaves have fallen in deciduous trees. My understanding of this, again based upon observations rather than plucking out of thin air is that the density based circulation provides a mechanism for keeping the tree not only topped up but is more than capable of providing an ever increasing head of water enabling the tree to continue growing away from the soil by adding an upward positive pressure at the tips of branches as well as providing a positive pressure to the phloem and a negative tension to the xylem that reaches from the roots to the water molecules in the soil. It is this incredible bonding quality of water that enables the tree to draw water to it’s roots from the soil and circulate it up to the leaves and back to the roots. Circulation is the key word here. Plants like ourselves and many other species do not lift water but circulate water! Circulating may require a pulley block and rope with buckets on it to understand it but not in the sense that it begins as an ampty

Raising the tube experiment from ground level to 24 metres over 10-15 years would not replicate the adhesive or cohesive structure of the tree either and would fail because the experiment is not designed to show an exact structure of a tree but to show how water can remain suspended in a tube over twice the height limit thought possible in physics and circulate fluids.

What I really wanted to hear in the forum was and is offers to help rather than offers to hinder progress. Dave Short did offer to help. Without the experiments being replicated it is infuriatingly difficult to show in words what is happening, in particular with the elasticity of water and tension.

Good News

A now retired doctor and physicist who I met some 15 years ago and who said then all those years ago he would be able to jointly write these experiments up for publication has again confirmed that his help will be forthcoming. This is what is needed: Practical sound advice and guidance. This is what makes a person stand out from the crowd!


This same doctor said after meeting me in person, at a University, as he looked out of his window: “today for the first time I truly understand a tree” without even seeing the experiments!

I have also said this and so have many academics and teachers.


OK, so that's your excuse for not doing bouble blind trials (not a very impressive one but...) .

What's your excuse for totally failing to do the maths?
What's your excuse for persisting with ideas that simply don't hold water when someone else looks at the numbers?


As things stand, if someone took up your ideas and ran with them and they actually turned out to be right then your epitaph might well be "Had some ideas about so-and-so but hadn't the abillity to follow it up with a proper explanation or investigation".
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 10/07/2009 23:11:13
Quote
Make no mistake B.C I know who and what I am up against!
Quite frankly, AKF, as far as I can see, you are up against yourself. If you really wanted to make this work then you would actually use history to help you instead of trying to play the tragic hero.
You don't read what anyone has written in these recent posts. You argue in one direction when the issue is in another direction. Has anyone doubted that you have seen results from your therapy experiments? Has anyone doubted the Brixham results?
What do you want to be 'remembered for', someone who found out something which could have been useful or someone who demonstrated just how wrong it's possible to be when you ignore all the facts?
I think you are reveling in all this opposition rather than trying to learn anything from what people have written.
Do you really think that the people on this forum are ruled by vested interests? You are exactly the same as the creationists and the Moon Landing Conspiracy proponents. The truth is clearly too complicated for you to understand so you have to make up your own home brewed ideas instead.
Such a shame. You want to be the one man in History who produced a brand new Science, all on his own. Everyone's out of step but you.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 11/07/2009 05:45:31
So wrong and so far off the mark about where this is heading Sophie. I do learn from you and others, my lesson might not go in the direction you anticipate but that is the problem with people who think laterally rather than a blinkered approach.

I have taken on board all of the posts and let's face it they are available for reflection and are being read by the doctor who has agreed to help with the paper. The real shame is that the significance of all of this appears to go over your heads.

You said science does not suck in that it can be explained better by pressure changes. The cohesion tension theory has an elaborate explanation stating that as one water molecule leaves the tree to the atmosphere another is drawn up to replace it. Well blow me if this was the case we would have water spurting out of the tops of buildings filled with cavity wall insulation and all of the water would leave the top of the tree rather than the observed source to sink flow.

Picture a deciduous tree in Autumn with all of it's leaves on the ground standing 40-50 metres as naked as a newborn. The cohesion tension theory states evaporation from the leaves causes water to be sucked up, SUCKED being the appropriate term for one molecule replacing another in a vertical chain from root to leaf. Well blow me again there are no leaves to suck here yet the buds begin to burst in the upper most branches during the spring. How does your precious historic science deal with this obvious anti-suck observation? It can’t can it? Only a density change be it from the warming of the outside of the tree or from the release of stored salts and sugars or even a combination of both can explain this new burst of life in what is after all a multiple conduit system consisting of predominantly non living tubular cells.

Another argument is that the collective pull of the densely leaved canopy can account for the impressive heights of trees. Well blow me again there are many trees locally that have very little canopy yet continue to grow vertically and have done so for some 21 years. Larch being a prime example.

The problem science is having at the moment is accepting that trees do not suck water up and emit it to the atmosphere, they circulate sap and some of it is emitted to the atmosphere and as a result of the water loss inevitable density changes take place!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 11/07/2009 09:43:14
No Science in all that. I'm afraid. You can relate as many instances as you like but that constitutes no proof of any principles.
In your circulation theory, would you be able to discuss the actual quantities involved? How much goes out at the top and how much goes down again (and then where does it go, laden with all these salts?).
Try thinking things through to their conclusion rather than giving us more purple passages.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 11/07/2009 10:13:54
Well blow me if this was the case we would have water spurting out of the tops of buildings filled with cavity wall insulation...
That's simply not true, is it?  If you really think that, they you do not have a grasp of the physics involved at all.

I'm with sophie, and pretty much everyone else.  We're bored of your waffle - do some science instead.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 12/07/2009 09:32:32
Cohesion tension theory states transpiration pulls on verticle columns of water dragging it up to the leaves from the soil! How? Why can't we see a model? Why should introducing a density change at the roots (adding salt to the soil) stop this imaginary process?

Why do the leaves bother to fall from the tree in the Autumn if they are so efficient at dragging water from the ground?

All answers welcome, here is a chance to do some "science"

Ben was speaking metaphorically about the constraints of the cohesion tension theory as it stands. Not literally but yes according to the tension theory if a brick evaporates water it should aslo apply the same tension to the water below so stacking one brick onto another should cause rising damp to travel to the tops of walls but it clearly does nothing of the kind.

If you are bored BenV, perhaps you should read something more interesting :)

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 12/07/2009 19:13:15


All answers welcome, here is a chance to do some "science"

Not literally but yes according to the tension theory if a brick evaporates water it should aslo apply the same tension to the water below so stacking one brick onto another should cause rising damp to travel to the tops of walls but it clearly does nothing of the kind.

If you cover the walls with a layer of waterproof material (I can't say I have tried tree bark- but it would be interesting) then that's exactly what happens. The water soaks up to the top and evaporates there.
Of course, without that cover, it evaporates before it reaches the top.
Scince is based on observation. My observation is that your assertion is false.
This tends to suport (though it does not prove) the opposite viewpoint.
In effect you have just proved your own ideas to be faulty.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 12/07/2009 22:21:09
AKF
Why do you introduce a nonsense question about why trees "bother" to shed [edit] leaves.
If large leaves were not shed they would rupture in frost and let infection enter. Any connection with your theory is spurious (not for the first time).
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 13/07/2009 10:42:24
AFK
Quote
A tree grows slowly and is filled with fluids from the onset so does not require fluids to be lifted to the leaves as per Sophies rope and bucket analogy

I just re-read this comment. Do you not see what rubbish it is? If a tree is 30m high, it GREW there. All materials needed to be lifted up there during the growing process. How long it took is irrelevant to the energy needed.

How can you expect to be taken seriously when you misunderstand elementary things like that?

If you accept that Energy is conserved in chemical and physical processes then you need to apply that principle in all of your ideas. You can't pick and choose what Science to use and what not to use. It's a consistent package - not mumbo jumbo, like your ideas.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/07/2009 20:32:30
Circulation of fluids is what counts as the tree grows, the tree maintains circulation using density changes caused by evaporation.

HOW ON EARTH CAN A TREE EVAPORATE WATER WITHOUT ALTERING THE DENSITY OF THE SAP inside the leaves and branches? does the tree somehow magically whisp the density away? Does it someohow suck sufficient water in from the atmosphere to replace the water it loses?

If 98% of all the water drawn through the roots evaporates through the leaves and the water inside the leaves contains a solution of sugar and salts surely some concentration of said salts and sugars will take place! Why have our learned bretheren overlooked something so blatantly obvious? Common sense lacking?

Easy question here...........



AFK
Quote
A tree grows slowly and is filled with fluids from the onset so does not require fluids to be lifted to the leaves as per Sophies rope and bucket analogy

I just re-read this comment. Do you not see what rubbish it is? If a tree is 30m high, it GREW there. All materials needed to be lifted up there during the growing process. How long it took is irrelevant to the energy needed.

How can you expect to be taken seriously when you misunderstand elementary things like that?

If you accept that Energy is conserved in chemical and physical processes then you need to apply that principle in all of your ideas. You can't pick and choose what Science to use and what not to use. It's a consistent package - not mumbo jumbo, like your ideas.


Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 15/07/2009 22:27:00
Andrew.  Where do you think plants get the material from which to grow?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 16/07/2009 07:29:13
Andrew.  Where do you think plants get the material from which to grow?

From the dilute solution of nutrients in the soil, water from the atmosphere, sugars from photosynthesis and carbon dioxide and oxygen from the atmosphere. http://biology.clc.uc.edu/Courses/bio104/photosyn.htm A link to refresh your memory Ben :)

Almost forgot to add some trees use bacteria to draw nitrogen from the atmosphere.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 16/07/2009 07:31:35
Now
AKF
Why do you introduce a nonsense question about why trees "bother" to shed [edit] leaves.
If large leaves were not shed they would rupture in frost and let infection enter. Any connection with your theory is spurious (not for the first time).
who is being nonsensical? How does a tree know there is about to be frost? Does it watch the BBC weather forcast as the leaves fall long before the first frost in most cases? No what happens is that increased rainfall introduces far more water into the tree diluting the sap. Coupled with huge increases in humidity and damp together with colder air causes the circulation in the tree to slow down and at times to the point of circulatory arrest. Density changes are also slowed down by a huge reduction in sunlight so again sugar production slows down and evaporation rates also slow down. Density in the sap at the leaf is reduced by the migration of solutes and nutrients away from the source to a sink causing the leaves to change colour as the tree effectively washes the life out of the leaves. Take the same tree to a more temperate climate and it seldom sheds leaves.

http://www.thenakedscientists.com/forum/index.php?topic=18299.0%3Bprev_next=prev   Dentstudent answers a question on leaf shedding.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 16/07/2009 07:56:40
Interesting, so according to you, cellar walls which have a ruberoid coating or membrane on the outside and an equally waterproof coating on the inside ooze water out of the top of the membrane rather than the membrane preventing the water from entering the brickwork? I have observed this following a heavy rain by the way and attributed it to the water table level rising and water running down the outide of the building to the basement wall rather than water percolating up the membrane. Fascinating, though I must admit that a swimming pool provides an excellent example of retaining the water inside it and I have never noticed water oozing out of the soil around the outside and one would have thought this should happen based on your post content, although there may not be an external waterproof barrier on a pool. A lot of buildings do have a waterproof coating and rendered exterior.

Thinking of a way I can test your post experimentally. Though I suspect what you may be refering to is a form of evaporative sweating with condensation reaching the upper part of the coated walls. Not quite the same as active water transport but a valid point on reflection.



All answers welcome, here is a chance to do some "science"

Not literally but yes according to the tension theory if a brick evaporates water it should aslo apply the same tension to the water below so stacking one brick onto another should cause rising damp to travel to the tops of walls but it clearly does nothing of the kind.

If you cover the walls with a layer of waterproof material (I can't say I have tried tree bark- but it would be interesting) then that's exactly what happens. The water soaks up to the top and evaporates there.
Of course, without that cover, it evaporates before it reaches the top.
Scince is based on observation. My observation is that your assertion is false.
This tends to suport (though it does not prove) the opposite viewpoint.
In effect you have just proved your own ideas to be faulty.




All answers welcome, here is a chance to do some "science"

Not literally but yes according to the tension theory if a brick evaporates water it should aslo apply the same tension to the water below so stacking one brick onto another should cause rising damp to travel to the tops of walls but it clearly does nothing of the kind.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 16/07/2009 10:22:19
AKF
Quote
HOW ON EARTH CAN A TREE EVAPORATE WATER WITHOUT ALTERING THE DENSITY OF THE SAP . . . .
Did anyone say that it could? Of course there will be dense solutions at the top. The question is whether there is enough to provide the motive power mechanism you propose.

Quote
If 98% of all the water drawn through the roots evaporates . . . . . .
So you are implying that the 2%, falling can lift the 98% for transpiration? Fantastic. We have a brilliant new way of making skyscraper lifts work, for free.
You are still locked onto this circulation theory with not a single numerical reason to justify it. If the numbers don't tally, there must be another reason. But of course, Maths is just there in order to discredit  the unqualified, isn't it?

Quote
Easy question here
An easy question but no answer, apparently, from you.

Quote
How does a tree know there is about to be frost? Does it watch the BBC weather forcast as the leaves fall long before the first frost in most cases?
You discredit yourself here, yet again.  If a tree could react quickly enough to avoid the damage of a chance frost then that would be a great energetic advantage - it would not have to grow more leaves after a mild winter. The action has to be taken in order to be on the safe side and it gets its clues from day length and night temperatures. Evergreen trees which survive extreme cold have other strategies than dropping leaves. They are subjected to exactly the same rainfall etc. as their deciduous neighbours - why don't their leaves fall of, according to you? Take a tree to a different climate and it may well react differently - but, if a species is to survive, this reaction will still be 'on the safe side'. Many equatorial trees will die if you put them in an English garden with English frosts, despite the fact that they get the same rainfall as the native plants - they will not drop their leaves deciduously but suffer from 'leaf drop' through injury by the cold.
If the leaf shedding strategy were not to protect against frost then why does it not occur so much in warmer climates?  During the monsoon, for instance. Autumns in the Eastern Seaboard of the USA are dry but the leaves are still shed.
But I don't see why you even introduced this line of thought. It is very typical that you don't deal with an objection - you just divert the flow of the argument.

BTW, it would help a lot if you posted your quotes before your replies, rather than after them. You launch into a tirade before declaring what you object to.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 16/07/2009 22:56:48
Andrew,
http://en.wikipedia.org/wiki/Damp-proof_course
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 17/07/2009 00:13:01
BC
That wiki page is not supported by references. There are better sources but few academic ones. I was looking.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 17/07/2009 09:37:53
Andrew,
http://en.wikipedia.org/wiki/Damp-proof_course

http://www.buildingpreservation.com/evaluating%20chemical%20dpcs2.htm here is a better one showing the level of rising damp. Not quite a hundred meters or more vertically and it does mention the salts from soil water being concentrated by evaporation.

From another source on rising damp.

The height to which the water will rise depends on
several factors including pore structure and rate of
evaporation. Masonry containing a high proporation of
fine pores will allow the water to rise higher than a coarse
pored material; basically the water is carried up the wall
in the finer pores and not those of large diameter. The
average size of pores in masonry gives a theoretical rise
of around 1.5 meters but where evaporation is severely
retarded, for example by the use of impervious
membranes, moisture can sometimes rise in excess of
2 metres.

capilary action was discussed earlier in this thread and the flow rates observed in trees could not be addressed, neither could the height of trees be considered when using capillary action. And the final objection is the dependency on capillary action of the diameter of the vessels. The diameter of the tubular cells in trees is often much greater than the fine capillary tubes used to demonstrate even a modest lift.

I have been photographing some tall trees that have a relatively few leaves yet appear to draw water from the ground for many years and are unaffected by their inherant lack of leaves.

How can the cohesion tension "hypothesis" address this serious and obvious flaw? Quite clearly it sucks in more than one aspect. I await your reply in it's defence.

Title: Re: How do Trees Really lift Water to their Leaves?
Post by: rosy on 17/07/2009 11:03:56
How can your theory that all drawing of water from the ground requires evaporation at the leaves to provide a density flow address this serious and obvious flaw?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 17/07/2009 17:52:35
AFK
Quote
some tall trees that have a relatively few leaves yet appear to draw water from the ground for many years and are unaffected by their inherant lack of leaves.
Do you purposely go for the non-sequeter every time?
Fewer leaves means less transpiration, which means less water is drawn up per hour.  Each leaf transpires one leaf's worth of water. What has "for many years" got to do with it?

I understand that the capillary action idea may not be satisfactory but why does that mean that yours is anything like a viable alternative?

You have avoided, as usual, a very important question applying to your idea. How much water goes up and how much water goes down? How can such a small amount of water going down provide lift for so much going up? Doesn't mechanics work in your world? Don't all the sums about energy and work mean anything to you - and I mean quantitatively, not armwavingly?
If I said that the bicycle chain going round makes your legs move as well as the wheels, I suspect that you would say I was daft. What you are saying is the equivalent of that.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 23/07/2009 12:23:33
Show us how a few leaves can suck water up tubes stretching a hundred metres when we struggle to suck water up a tube a metre high.

Explain how the buds get water delivered to them when there is not a single leaf on a tree?

Explain Strasburger's observations with circulation taking place for several weeks in a tree that has every single living process killed by introducing picric acid into it at a severed trunk immersed in a bath full of the stuff.

I repeat the Cohesion tension hypothesis sucks and is nonsense and deserves it’s rightful place deep within a fictional blackhole.

Nice try on the rising damp but one that has been put forward several times over the years and in this thread capillary action was debunked as it could not address the diameters of the tubes involved and the flow rates observed, let alone the heights achieved by trees..




AKF
Quote
HOW ON EARTH CAN A TREE EVAPORATE WATER WITHOUT ALTERING THE DENSITY OF THE SAP . . . .
Did anyone say that it could? Of course there will be dense solutions at the top. The question is whether there is enough to provide the motive power mechanism you propose.

Well yes someone has said the density changes will not take place because more water will arrive to re-dilute it and take it’s place. This of course does not prevent the change in density but merely supports a circulation theory rather than a redundant one way ticket to the atmosphere hypothesis.




Quote
If 98% of all the water drawn through the roots evaporates . . . . . .

Quote
So you are implying that the 2%, falling can lift the 98% for transpiration? Fantastic. We have a brilliant new way of making skyscraper lifts work, for free.
You are still locked onto this circulation theory with not a single numerical reason to justify it. If the numbers don't tally, there must be another reason. But of course, Maths is just there in order to discredit  the unqualified, isn't it?

Well it appears to work for the Californian Redwoods and a few other magnificent specimens towering well over a hundred metres. Did anyone observe a mechanical lift used in their construction?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: BenV on 23/07/2009 12:44:20
Andrew, the current explanation may be inaccurate.

Right now, yours is a long way from being complete enough to even faintly threaten it.  Stop whinging and do the science.  Start with the sums, as sophie has been asking you to do for ages.

Until you do that, you're pissing in the wind.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 23/07/2009 15:13:36
AFK
You seem to have got your quotes in a twist in your last post. Just WHO said WHAT??

(As sloppy with your use of the square bracket as with your use of Science).

I am still waiting for some figures to back up your nonsense. Did the redwoods just appear there or did they have to ~GROW up to that height, carrying their materials with them? (Edit)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 23/07/2009 19:53:55
BC
That wiki page is not supported by references. There are better sources but few academic ones. I was looking.
I grant that it's not supported by references but all I needed to do was show that there is some evidence that such things exist. If Andrew wanted to he could have searched elsewhere. I would, had he asked, have sugested that he looked at the walls of his own house.

This page
http://en.wikipedia.org/wiki/Mathematics
is quite well referenced and I wonder if we could explain its importance to Andrew.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 23/07/2009 21:21:23
BC.
It's just mumbo jumbo, you know. It's not repeatable and you have to be a professor to use it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 24/07/2009 05:49:43
Why does AKF bother to post at all if he is unwilling to properly address critique?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 24/07/2009 20:38:17
I think he thrives on adverse criticism of his ideas. It saves him having to examine them too closely, himself, because he can. instead, get blindly defensive about them.

There's a lot of inverse technical snobbery there, I think.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 25/07/2009 06:58:05
Wonderful. And you can't ignore him either, lest people start taking him seriously.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 31/08/2009 13:49:46
Modeling xylem and phloem water flows in trees according to cohesion theory and münch hypothesis

HÖLTTÄ T. (1) ; VESALA T. (1) ; SEVANTO S. (1) ; PERÄMÄKI M. (2) ; NIKINMAA E. (2) ;

(1) Department of Physical Sciences, University of Helsinki, P.O. Box 64, 00014, FINLANDE
(2) Department of Forest Ecology, University of Helsinki, P.O. Box 24, 00014, FINLANDE
Abstract
Water and solute flows in the coupled system of xylem and phloem were modeled together with predictions for xylem and whole stem diameter changes. With the model we could produce water circulation between xylem and phloem as presented by the Münch hypothesis. Viscosity was modeled as an explicit function of solute concentration and this was found to vary the resistance of the phloem sap flow by many orders of magnitude in the possible physiological range of sap concentrations. Also, the sensitivity of the predicted phloem translocation to changes in the boundary conditions and parameters such as sugar loading, transpiration, and hydraulic conductivity were studied. The system was found to be quite sensitive to the sugar-loading rate, as too high sugar concentration, (approximately 7 MPa) would cause phloem translocation to be irreversibly hindered and soon totally blocked due to accumulation of sugar at the top of the phloem and the consequent rise in the viscosity of the phloem sap. Too low sugar loading rate, on the other hand, would not induce a sufficient axial water pressure gradient. The model also revealed the existence of Münch counter flow, i.e., xylem water flow in the absence of transpiration resulting from water circulation between the xylem and phloem. Modeled diameter changes of the stem were found to be compatible with actual stem diameter measurements from earlier studies. The diurnal diameter variation of the whole stem was approximately 0.1 mm of which the xylem constituted approximately one-third.
Revue / Journal Title
Trees   ISSN 0931-1890   CODEN TRESEY
Source / Source
2006, vol. 20, no1, pp. 67-78 [12 page(s) (article)] (43 ref.)
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 31/08/2009 18:51:16
AKF
Very interesting but does it say anywhere that the whole thing is "driven by gravity", which is the claim you make and with which I (several of us) disagree? I don't think anyone has a problem with the idea that solutions flow around plants. I don't think you have posted anything to support the gravity idea, have you?
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 31/08/2009 19:12:29
AFK
Quote
A tree grows slowly and is filled with fluids from the onset so does not require fluids to be lifted to the leaves as per Sophies rope and bucket analogy

I just re-read this comment. Do you not see what rubbish it is? If a tree is 30m high, it GREW there. All materials needed to be lifted up there during the growing process. How long it took is irrelevant to the energy needed.

How can you expect to be taken seriously when you misunderstand elementary things like that?

If you accept that Energy is conserved in chemical and physical processes then you need to apply that principle in all of your ideas. You can't pick and choose what Science to use and what not to use. It's a consistent package - not mumbo jumbo, like your ideas.



Your blinkered approach is limiting Sophie. Circulation of fluids is all that is required, not a one way indian rope trick but a gentle rotation of fluids where the downward flow provides an increase head of flow in the return / xylem side providing the impetus for vertical growth.

The paper abstract mentions circulation when transpiration has stopped. read it.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: lyner on 04/09/2009 00:12:01
Blinkered or careful? My question was whether the reference supports your gravity idea. If it does then you could, perhaps, cut and paste the paragraph for us.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Mr. Scientist on 15/09/2009 23:45:44
Osmosis Capillary action and root pressure are accepted as the driving force for lifting water to the canopy of a giant Californian Redwood, towering a hundred metres and more? And these forces are producing flow rates up to and in excess of a 1000 litres a day in a single tree?

Another theory is that the leaves, which are porous, can somehow suck water from the soil and evaporate it through the pores of the leaves? Ever tried sucking on a straw with a hole in it?


Maybe there is another explanation:

Herald Express, July 6, 1995, page 19.   (local paper in Torbay, Devon)

Eureka!

Picture headers, text and pictures removed.
Cliff experiment pulls plug on 300 year old law of physics

http://www3.sympatico.ca/slavek.krepelka/exper/EUREKA.gif

A Revolutionary breakthrough claimed by a Paignton man is to be investigated
by top scientists.
Ideas man Andrew K Fletcher claims he has disproved a fundamental law of
physics dating back to the 17th century.
And impressed by the historic experiment at Overgang cliff, Brixham, to
raise water 78 feet without the support of any artificial aids,
John Hunt, Senior forestry Officer for Devon and Somerset who witnessed the
experiment's success last Friday said: 'It was quite impressive.

The rule that water will only rise 32 feet under atmospheric pressure when
in a column was effectively disproved."


But Mr Hunt explained that he is a professional forester not a scientist and
a report on the experiment would be sent to the Forestry commission 's Alice
Holt Research Station,
near Farnham in Surrey, for further investigation.
Mr Fletcher's experiment involves a long water filled plastic tube, strung
up the cliffside with both open ends placed in two filled demijohns.
A small amount of a salt solution is added at the top of the tube
before it is completely filled with water, this acts as a liquid pulley says
Mr Fletcher, lifting water from one demijohn to the other, thereby
disproving Torriceli's 17th century law.
This explains how trees can raise water to their tops beyond the 32 feet
limit."
said an ecstatic Mr Fletcher. He believes that the discovery also suggests a
mechanism by which all life on earth has evolved from the ground.

The Experiment at Brixham Overgang Cliffs where water flowed vertical up a single 6 mm bore tubing using 10 mils of salt solution, demonstrating that a tiny amount of denser solution can lift effortlessly many thousands of times it’s own volume in water without any artificial aids, demonstrating clearly a non living physical cause of bulk flow in plants trees, animals and humans. The 10 metre limit for lifting water clearly needs some serious revision. View The Historic Event on Youtube as it unfolded all those years ago and ask why has this important discovery been ignored for so long.


Video of the Brixham Experiment on Youtube:
Video introduction to density flow on Youtube:
Video of a scaled down version of the Brixham Experiment on youtube:
Video of a simple experiment to show density flow in boiling sugar syrup.

http://andrewkennethfletcher.blogspot.com/


Andrew K Fletcher


Online Theory with Gif animation:http://www3.sympatico.ca/slavek.krepelka/exper/ScienceRevw.htm




Medical Physics Newsletter publications:

http://groups.iop.org/ME/archive_newsletter2002010.htm

http://groups.iop.org/ME/archive_newsletter2003014.htm

 
OK Let's start with Osmosis
The work Of Professor H.T.Hammel:
EVERYTHING YOU WERE TAUGHT ABOUT OSMOSIS IS WRONG.


Osmosis is the reason that a fresh water fish placed in the ocean desiccates and dies. Osmosis is the reason that blisters form on fiberglass boat hulls. Osmosis is how waste products of metabolism enter and leave the blood stream. Osmosis determines how you, me and every living thing lives and dies. One would think that a civilization that spends billions of dollars every year on medical research would understand something as basic as osmosis. Wrong, wrong, wrong.
Source: http://www.yarbroughlaw.com/Osmosis.htm
 
Or what about Root Pressure?

Roots can squeeze water to the tops of trees? You what?. ROFLMAO. Sorry but every time I read about root pressure it makes me cringe.

Or maybe capillary action? In other words, a tree is a giant sponge capable of blotting water from below ground level to heights in excess of a hundred metres at flow rates that can exceeding a thousand gallons of water a day in a single tree.

Does the cohesion tension theory suck? How can leaves create suction when there are pores in them open to the air? Is it not like trying to suck water through a straw with holes in it?


Andrew
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi209.photobucket.com%2Falbums%2Fbb31%2FAndrew_K_Fletcher%2FWeb%2520Page%2520Pictures%2FEUREKA.gif&hash=24ad69b516ab10722551d4d631dd43bc)

You could think of the leaves breathing the evaporation, but this is especially new to me...

I must read more of this thread.
Title: How do Trees Really lift Water to their Leaves?
Post by: davlin47 on 27/10/2009 08:30:33
Hello


Leaves Are Plant Food Factories *

Plants and other photosynthesizing organisms have a very special talent. They can turn sunlight into food. It is a pretty neat trick that only photoautotrophs can do (photo=sun; auto=self; troph=feeder).

In order for plants to make food energy, they need water, carbon dioxide (CO2) and sunlight. From this special combination, a plant is able to make its own food, in the form of glucose, a type of sugar. Plants then use the glucose as food energy to live and grow. In order to harvest sunlight energy, plants have a green pigment called chlorophyll. This pigment is what makes a plant's leaves appear green.

* Shutting Down Operations for the Winter *

As winter approaches, the days get shorter and cooler. This change in day length and temperature triggers some trees to go dormant, essentially hibernating for the winter. A tree's woody roots, branches and twigs can endure freezing temperatures, but most leaves are not so tough.

It is also very energetically expensive for a tree to run its leafy food factories in the winter, when there is often little sunlight and freezing temperatures make water transport (from the ground into the tree's trunk and leaves) a problem. So it's more energy efficient for a leafy tree to close down operations in the winter and go dormant.

* How Leaves are 'Told' to Drop *

A tree is full of vascular cells that transport water and sap throughout, from root to leaf tip. As the amount of sunlight decreases in autumn, the veins that transport sap into and out of a leaf slowly close off. Then a layer of cells, called the separation or abscission layer, develops at the base of the leaf's stem. When this layer is completely formed, the leaf falls off.

This process happens in all deciduous trees (trees that annually shed their foliage), with oak leaves as a notable exception. In oaks, the separation layer doesn't fully allow the oak leaves to detach. That's why most dead oak leaves remain on the tree through winter and even into early spring (much to the perpetual leaf-raking consternation of home owners with oak trees on their property

Thanks for sharing
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 08/11/2009 09:46:48
Hello Davlin

Your welcome :)

The thread deals with what happens to the glucose and dissolved minerals in the sap after evaporation at the leaf. Curent theory relies on transpiration to pull water up from the ground. However, when the leaves have fallen very little transpiration if any is taking place so clearly another method of fluid transport is relied upon.
Title: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 08/11/2009 13:45:23
Why would trees that have lost their leaves need any significant water uptake at all? Climates in which deciduous trees evolved are cold in winter, so tree metabolism and water-loss is reduced. Sap can even freeze. Any slight water loss could probably be compensated for by stomata in the stems. So what's the problem?

Also, how does photosynthate transport affect your hypotheses?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 09/11/2009 10:09:53
Trees inevitably evaporate water even when leaves are not present and water will leave the tree and enter the soil if the circulation within is interrupted.

How does the current literature deal with this problem in deciduous trees?  After all there are no leaves to effect this imagined magical pull on each of the water molecules yet the water inside the naked tree is happy to circulate to the highest twigs and branches?

A big clue is the migration of minerals and sugars to the roots over the winter period.

Gravity cannot be ignored no matter how inconvenient the truth is.

The fact that the solutes have migrated to the lower part of the tree means that the more dilute sap must have been drawn and pushed up to replace the falling sap. This will inevitably apply tension to the soil water molecules and draw in water and diluted minerals which in turn alter the density of the sap at the roots causing a density imbalance which must be corrected by rising up the tree caused by the tension from the falling sap! Affording circulation to continue unhindered when leaves have fallen.

http://en.wikipedia.org/wiki/Transpirational_pull
The Incoherent Cohesion Tension Hypothesis.
Title: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 09/11/2009 12:02:26
Do you accept that transpiration is the major factor in water transport in leaved trees?

Have you demonstrated experimentally and mathematically that density changes are enough to cause water transport?

In winter, metabolism slows down and sugar production at the top of the tree stops.  So once that sugar (and other nutrients produced in the leaves) have sunk to the bottom of the tree, the tree's water transport power is significantly reduced. What does the tree do then? Are dissolved minerals really enough?

Trees have thick bark and waxy coatings that prevent water loss. Can you demonstrate that any water loss that does occur is significant enough to endanger the tree in winter? Or if water that's lost is replaced by your proposed mechanism, can you demonstrate that this is the case?

I would appreciate direct answers :)
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2009 10:37:12
Thanks for the questions Stefan.

Stated many times that evaporation is required to alter the density of the sap in the upper part of the tree, releasing pulses of salts down the phloem to induce a positive pressure in front of the falling sap and a negative pressure / tension on the xylem sap affording bulk flow back to the leaf. So clearly transpiration is important when leaves are on the tree but not required for inducing the circulation when there are no leaves on the tree. Yet the stored solutes in the upper parts of the tree as you rightly state move down the tree over the winter towards the roots and this cannot take place without affecting a return flow of dilute sap back up the tree.

Even when the tree has shed it's leaves root growth requires there to be circulation and the change in pressures brought about by shedding the leaves would undoubtedly influence a downward growth at the roots providing an increase in pressure within the roots.

Have already demonstrated circulation inside tubular experiments using tea, liberated from tea leaves, urine, milk, juiced fruit, juiced leafy vegetables, demonstrating slight changes in density at an elevated point will cause both a downward flow and a return flow.
1.      2.   3.   

Mathematical calculations designed to show it can't happen or can happen appears a little pointless when we can show it taking place experimentally and reliably so. Has anyone done the maths on the Atlantic conveyor system? If you feel this can contribute anything please feel free to share your results.

Over a prolonged winter when hypothetically all of the sugars and salts have reached the roots which incidentally could not happen without a continual flow and return circulation taking place, all that would be required to trigger circulation in the spring would be a density change in the sap. Warming the outer part of the trunk first from the seasonal change in temperature would provide such a density change and induce circulation together with an increase in head of water at the tips of the branches to induce bud burst and the blooms of blossom and leaves.

Also, the last ice age that is believed to have been started by a sudden influx of salt free water flowing onto the ocean surface and causing the Atlantic Conveyor system to shut down. See film: After the Warming. Offers an understanding of the sudden increase in rainfall in the Autumn diluting the sugars and solutes in the tree and effectively washing out the nutrients from the leaves returning them to the trunk and branches and in doing so altering the circulation causing the leaves to wilt and fall.

The fact that the leaves fall from the tree indicates they are in danger given that the deciduous trees that normally shed leaves hang on to them when planted in warmer dryer conditions. And when a tree is in trouble from water stress it is generally the upper parts of the tree that die back again indicating a reduction in water within the tree.

Andrew
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 10/11/2009 11:34:18
Quote
Mathematical calculations designed to show it can't happen or can happen appears a little pointless when we can show it taking place experimentally and reliably so. Has anyone done the maths on the Atlantic conveyor system? If you feel this can contribute anything please feel free to share your results.

Yes, Andrew, but current theory can explain your observations in loops closed at the top. I've yet to hear of a system in which you've managed to extract the water (and therefore the kinetic energy) once it reaches the top of the system.

Have you done the experiment? Explained how it might work in a tree?
It still looks like a perpetual motion machine to me...
Title: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 10/11/2009 13:22:06
Thanks for your reply Andrew.

I second Rosy's post.

What I meant to convey when I asked what does the tree do when its photosynthates have sunk, was, what if this occurs long before Spring arrives?
And is the concentration of salts normally found in water enough? Do you use the correct (natural) concentrations, as well as tube diameter, in your experiments?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2009 16:52:36
Hi Rosy

The Atlantic Conveyor system does not require tubes, yet evaporates water from the "top" and circulates a phenomenal amount of sea water without much problem.

The tubular experiments are as I have stated many times a method of showing the circulation caused by the density differences, not a method of showing a tree. If we needed to show this we only have to go back to Strasburger's experiments with picric acid to see that the tree structure is capable of both evaporation and circulation for 3-4 weeks following the complete death of the tree.



The cohesion tension hypothesis you are defending does not have any working model.
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 10/11/2009 17:06:30
Thanks for your reply Andrew.

I second Rosy's post.

What I meant to convey when I asked what does the tree do when its photosynthates have sunk, was, what if this occurs long before Spring arrives?
And is the concentration of salts normally found in water enough? Do you use the correct (natural) concentrations, as well as tube diameter, in your experiments?

That's the point.  For the salts and sugars to percolate down to the roots it will take a long time, because any movement down will result in a return flow and the return flow will lift significant amounts of solute back up providing the return flow is more dilute than the downward flow.

This will counter act the imagined sudden influx into the root system when the trees leaves fall.

But supposing most of the solutes have arrived at the roots several months before the spring. We would still observe sap rather than pure water in the tree and sap always contains some dissolved salts and sugars.

Having thought about this problem it may also be that the more dilute sap will dissolve stored sugars and minerals from the bulk of the tree, just as the trees leaves lose their sugars and solutes, so providing we don't have a winter that overstays it's welcome the tre should be able to continue to circulate the sap for the duration of the colder weather. Furthermore the freezing temperatures would cause the sap to thicken and this too could delay the shift in solutes towards the roots for a longer period.

Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 10/11/2009 19:06:21
"Mathematical calculations designed to show it can't happen or can happen appears a little pointless when we can show it taking place experimentally and reliably so."

Bollocks.

If I said that the movement of the water in the tubes was due to the gravitational influence of the planet Mars then some simple calculations would show that my suggestion is rubbish.

About a zillion years ago on a related thread where you were claiming that the differences in density were responsible for the actions of the kidneys (or some such thing) I did the maths to show that you were seeking to rely on an effect that was far too small. You can use maths to rule out an idea and you can also use it to show that an idea might be valid.

We know that water gets to the tops of trees.
What we are debating is whether or not your suggested idea might be responsible or whether it might be the conventional explanation.

To support your idea we need you to provide the maths which either shows that the conventional view is wrong or that your ideas about density are plausible.
Without them you are hardly in the realms of science.
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 11/11/2009 09:32:45
Well go ahead and provide the maths then
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 11/11/2009 09:45:02
Looking forward to your mathematical explanation as to how trees can evaporate 98% of all the water drawn through the roots at the leaf without affecting the density of the sap and how gravity cannot affect the migration of density changes in the canopy and how that migration cannot affect the movement of more dilute sap back to the leaf as it takes place.

Good luck!
Title: How do Trees Really lift Water to their Leaves?
Post by: BenV on 11/11/2009 12:19:36
You seem to have ignored this bit again Andrew:

To support your idea we need you to provide the maths which either shows that the conventional view is wrong or that your ideas about density are plausible.
Without them you are hardly in the realms of science.

Fair enough, you are convinced by your ideas - but you cant expect anyone else to be if you don't do the work.

You mentioned a while ago that you are working with a retired pyhsicist friend to refine this.  He would, I hope, agree that the maths is essential.

Think of it this way - if a flea can jump 50 times it's body height, we don't take this as undoubtable evidence that a man sized flea can still jump 50 times it's body height.  We could, however, calculate the energies required and available, and work out whether or not it could.  The maths will tell us if our model is appropriate.
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 11/11/2009 18:56:02
"Looking forward to your mathematical explanation as to how trees can evaporate 98% of all the water drawn through the roots at the leaf without affecting the density of the sap "
That doesn't need a lot of maths.
As long as the rate that the water is lost is that same as the rate at which it enters then the net concentrationin the sap remains constant and ther's no change in density.

However as I (and others) have pointed out before,
IF YOU WANT TO BE TAKEN SERIOUSLY YOU NEED TO PROVIDE THE MATHS.

If your next post doesn't include that maths then we can all assume that you are trolling and ignore you.
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 12/11/2009 09:13:52
"Looking forward to your mathematical explanation as to how trees can evaporate 98% of all the water drawn through the roots at the leaf without affecting the density of the sap "
That doesn't need a lot of maths.
As long as the rate that the water is lost is that same as the rate at which it enters then the net concentrationin the sap remains constant and ther's no change in density.

However as I (and others) have pointed out before,
IF YOU WANT TO BE TAKEN SERIOUSLY YOU NEED TO PROVIDE THE MATHS.

If your next post doesn't include that maths then we can all assume that you are trolling and ignore you.

Common sense appears to be sadly lacking.


1.   Of course the loss of moisture at the leaf will change the density of the sap.
2.   More water arriving at the leaf will replace the denser sap, which has inevitably been moved from the leaf due to the effect of gravity on said solutes.
3.   If the cohesion tension theory was correct as it stands, which incidentally it falls far short of being correct as a result of all of that evaporation from a one way trip to the leaf and ultimately the atmosphere, would you expect the salts and sugars to remain inside the leaf? If so why are the leaves able to avoid crystallization from the huge amount of sugars and salts accumulating?

Look into irrigation on arid soils to see that salt build up due to high evaporation rates becomes a problem

Are you really that blind or just as you stated ignorant? Troll indeed.
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 12/11/2009 10:48:37
1. Yes, no-one said different.
2. Well, sort-of. "Sap" doesn't just move in and out of leaves like fluids round your plastic-tube experiments, it has to undergo transport across cell membranes. Apart from that, yes, denser liquids (on average) move down, and are replaced by less dense liquids.
3. No. I wouldn't expect the salts and sugars to remain in the leaf. This is a total straw man and you are avoiding doing the maths.

Our problem with your theory, as I have explained at length elsewhere, is that you have not accounted for sufficient energy being available to the system to lift the amount of water you're claiming it must lift. Since you've been expounding this theory, on this thread, for four-and-a-half years now, this is an extraordinary omission and, frankly, seems to me to justify BC's inclination to characterise you as a troll. My own assessment runs more to "faith nutter" but the two are not mutually exclusive (troll need not always, after all, imply malice).
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 12/11/2009 16:55:22
And I have stated many times that the density change in the phloem sap gives the xylem an increased head or in simple terms raises it above the level of the phloem. Sophiecentaur related this to how locks between saline and fresh water show the different levels.

Therefore as the tree grows right from a seed, the dilute sap pushed higher and higher, as the phloem continues to support the less dense sap at a higher elevation than the falling sap, of course the tree does not directly afford the increased head of water but the pressure differences albeit minor affords the tree a direction to grow in with ease.

This is shown clearly in the video link provided using a water filled U tube. The density difference shows clearly the change in water levels.

How do you suggest we account for this in maths?
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 12/11/2009 17:45:29
OK. This is what we mean:

You can calculate (easy physics) the energy required to raise a certain mass through a given distance (E=mgh, energy in joules = mass in kg x g x height in metres where g acceleration due to gravity and is 9.831 metres per second per second)

So to raise 1 kg by 1 metre using gravity, you must lower 1 kg by 1 metre to balance it (or 2 kg by 0.5 m or 0.5 kg by 2 m).

Your claim that gravity can drive the transport of fluids in plants therefore demands that to move 1 kg of water from the roots to the leaves, you must lower 1kg of something-or-other.
Some of that will be water, but if we assume that 90% of the water taken up by the roots is lost in transpiration*, that means that for every 1 kg of water that moves up the tree, 900 g of sugars (principally sugars, as most salts and nitrogen containing compounds have to come up from the roots in the first place) must be produced and moved down**.

Infact, crops transpire*** between 200 and 1000 kg of water for every 1 kg of dry mass (sugars plus all the other stuff) they produce.

If we could get that sort of biomass production out of trees there'd be much less call to be worrying about fossil fuels!!

OK, there's my first stab at the numbers. Can you point out how your system gets passed this apparently insurmountable energy barrier? Or not?


*(I got the figure off wikipedia, but it's a reasonable number and is something that's been measured lots of times)

**(even without accounting for the fact that water is used in sugar synthesis and making 900g of sugar would use of the order of 450 g of water)

***(again from wikipedia)
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 12/11/2009 18:53:26
"1. Yes, no-one said different."

Well, actually I did say differently.

You start with a gram of sap. It loses a tenth of a gram of water by transpiration and gains a tenth of a gram of water drawn up from the roots.
You have exactly the same thing as you started with so the density is the same as it was.


Anyway, since Andrew is quite passionate in his refusal to even try to show us some numbers I think it's fair to assume that he knows that wouldn't support his point of view.
Until I see him prove otherwise I don't see anything changing my opinion on the matter.
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 12/11/2009 22:47:49
Yeah, alright BC, you have a point. Sorry.

I think there's a (very sloppy) argument (or isn't there?) that some of the water drawn up the xylem (as part of a less-dense) solution then becomes part of a (more dense) solution in the phloem, so in that sense a solution gains density (if you ignore the whole transport into/out of cells thing that has to happen at the top, which you can't really).

And you're probably right about Andrew too, not sure why I bother... but somehow I keep on coming back in the hope some day he'll catch on.
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 13/11/2009 09:46:57
I keep coming back also in the hope that someday you will all catch on!

Those pictures of varicose veins resolving by tilting a bed the opposite way to that recommended by the medical profession is not unrelated to this discovery as has been suggested in the past.

I tilted the bed in the first place to test if a flow and return in the body was present. If it was then a swollen vein would reduce in size. Precisely what happened and is happening to many people.

Yet conveniently ignored by people who should know better!

Very difficult to ask a tree if gravity is having an affect. But very easy to ask a person to lay on an angle and observe the changes!

You may not like the fact that someone outside of academia has delivered a profound discovery and frankly I couldn’t give two hoots what belief based system you adhere to.

The experiments shown on Youtube speak volumes more than an imagined impossible leaf based pull on a 100 plus meter Californian Redwood.

Show me the numbers that support this absurd belief?

Better still take a look at what the students think about it: http://www.thestudentroom.co.uk/showthread.php?t=599353

The cohesion tension hypothesis relies on a continuous bead of water to support a column and the evaporation at the top of the column can not only support the fluid but can pull it up the trunk and release it into the air.

But we know that cavitation takes place all of the time and that any break in the bead of the imagined cohesion tension generated by a flimsy leaf flapping around in the breeze would render the whole process redundant. Yet the tree appears to not be affected by the constant cavitations, which can be heard cracking with a standard stethoscope.   But that’s accepted and to be expected in a belief -based system.

You can’t ignore this fact!


The following relates to the cohesion tension hypothesis.
http://4e.plantphys.net/article.php?ch=&id=99


Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 13/11/2009 10:11:22
Andrew

If you got over your puerile inverse-snobbery for just long enough to give our criticisms of your system serious consideration, you would do one of two things. Either you would strengthen your argument immeasurably, or alternatively (and I grant you I think it's more likely), you'd realise that your model is untenable and be able to go away and refine it/not spend the rest of your life beating your head against the internet.

If you don't address this very specific question, you will be a fool in ways that have nothing to do with academic qualifications one way or another, but everything to do with blind arrogance.
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 13/11/2009 10:23:21
Quote
But we know that cavitation takes place all of the time and that any break in the bead of the imagined cohesion tension generated by a flimsy leaf flapping around in the breeze would render the whole process redundant. Yet the tree appears to not be affected by the constant cavitations, which can be heard cracking with a standard stethoscope.   But that’s accepted and to be expected in a belief -based system.

Bunk. Trees grow outward, too, you know. They grow new xylem and phloem tissue which is filled with fluid as the cells grow. Sure some of them break, that's why new ones are required.
Plus of course you've shown (bully for you) that even with an enormous diameter tube (relative to a xylem) it is perfectly possible to raise a column of water above 10 m (not an equilibrium system, but then life has very few equilibrium systems), and given a much finer column and therefore very different surface behaviour between the xylem fluid and the inner surface of the xylem, your "argument from incredulity" doesn't wash there.

Just because you don't believe it can happen, doesn't mean it doesn't.
On the other hand if the energy accounting doesn't work out you better have a pretty damn good explanation because you've just declared all trees to be perpetual motion machines on a grand scale.

Your inclined bed theory has nothing to do with trees and might stand a better chance of not "being ignored by people who should know better" if you made at least some effort not to come across as a fool. After all, the first google result for "Andrew K Fletcher" (and therefore the first thing someone wanting to find out more about this person who's sent them information about his new theory for solving all of medecine), is your Naked Scientist Forum profile. Which will bring them straight here. The majority of people in the category of "people who should know better" are likely to feel much as I do about your total refusal to interact with our very specific criticisms of your pet theory.
Title: How do Trees Really lift Water to their Leaves?
Post by: BenV on 13/11/2009 11:07:18
Sorry to jump back to my earlier example, but...

Are you saying, Andrew, that a man size flea would be able to jump to the same equivalent height as a normal size flea?

By ignoring the need for the maths, this is exactly what you are doing.

Once again, your own arrogance belies the fact that you have not done the work needed to prove yourself right - is it that you are too scared that you'll prove yourself wrong?

It certainly appears that way.

"Belief -based system" indeed.
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 13/11/2009 14:04:58
The cavitations repair themselves, cavitations are taking place all of the time and emit lou8d cracking sounds. This does not result in the collapse of the circulation in the tree and this is where the problem with the cohesion tension hypothesis lies.

Have you any idea of how much pressure would be required to support the columns of water in tall trees using the cohesion T model? Do you not think that the leaves would literally become inverted under such immense tension or even sucked down the trees vessels for that matter?

Pete Scholander and Ted Hammel hit the nail on the head when they made the pressure bomb and began recording pressures far above those proposed and required by the CTT.

So ask yourself if this imaginary impressive tension is not present in tall trees how on earth are they able to conform with the rest of the theory?

Can you not see how absurd it is to propose that leaves can suck up water from the roots no matter how it is wrapped up?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 13/11/2009 14:17:50
Ben let us look at those maths in the Cohesion tension hypothesis first.
http://4e.plantphys.net/article.php?ch=&id=99
The application of the Ohm′s law to sap flow encompasses many phenomena (heat transfer, water transfer in soil, Darcy law, first diffusion law, etc.) and, it is therefore independent of the underlying physical mechanisms and the nature of moving fluid. For example, the electrical approach does not address whether sap is under tension or pressure. For this reason, the description of sap flow by Ohm′s is rather "phenomenological".

Had to look this word up: http://en.wikipedia.org/wiki/Phenomenology_%28science%29
Phenomenology in physical sciences

There are cases in physics when it is not possible to derive a theory for describing observed results from the known first principles (such as Newton's laws of motion or Maxwell's equations of electromagnetism). There may be several reasons for this. For example, the underlying theory is not yet discovered, or the mathematics to describe the observations is too complex. In these cases sometimes simple algebraic expressions may be used to model the observations or experimental results. The algebraic model is then used to make predictions about the results of other observations or experiments. If the predictions made by the algebraic model are sufficiently accurate, they are often adopted by the scientific community despite the fact that the algebraic expressions themselves cannot be (or have not yet been) derived from the fundamental theory of that domain of knowledge.

The boundaries between theory and phenomenology, and between phenomenology and experiment, are fuzzy. Some philosophers of science, and in particular Nancy Cartwright argue that any fundamental laws of Nature are merely phenomenological generalizations.


Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 13/11/2009 14:41:14
You keep on about how we're tied to the current explanations. Some of the other people you're talking to may be, I'm not. Indeed, I have little knowledge of how biologists (or indeed anyone else) explains exactly how trees work.

However, what I am interested in is the basic physics of this situation. You keep on, and on, and on, about how your macro experiments support your micro interpretations. All I'm saying is that they don't. Your experiments (certainly the ones I've seen), don't show diddly-squat of any relevence.

As you rightly say, what we "know" about science is quantified interpretation of experimentaly data and, often, there are gaps in exactly how far we can explain the origins of those quantitative relationships between this, that, and the other thing. And certainly much (or argualbly all) of biology falls into that category. On the other hand one of the most (possibly the most) tried, tested, and still undefeated bits of science is thermodynamics. In energetic terms, you don't get something for nothing. Just doesn't happen (or not anywhere so far demonstrated, anyhow).

Gravity just cannot provide enough energy from falling sap (even if we overlook all the other flaws in your arguments, which are many). So how do you account for that? If you can't account for it then your theory has no scientific merit at all. And I will carry on thinking you a deluded fool, not just for wasting so much of your time and energy pushing your dead-end assertions about gravity, but also for your abject failure to look for the real causes of your apparently successful inclined bed ideas. If your results in that are really are as good as you claim it's not only yourself you're failing by apparently trying your best to discredit them with everyone who knows one end of an equation from the other.

In other news, if leaves can't support the "suction" of a column of water below them, how exactly are the (if anything more fragile) root systems of these great trees supposed to support the colossal pressure above them?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 14/11/2009 08:57:59
Journal of Experimental Botany, Vol. 48, No. 315, pp. 1753-1765, October 1997
Journal of
Experimental
Botany
REVIEW ARTICLE
The Cohesion-Tension theory of sap ascent: current
controversies

Melvin T. Tyree 1
USDA Forest Service, Aiken Forestry Sciences Laboratory, PO Box 968, S. Burlington, VT 05402, USA
Received 12 February 1997; Accepted 21 May 1997
http://jxb.oxfordjournals.org/cgi/reprint/48/10/1753.pdf


Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 14/11/2009 09:02:38
Gravity does not provide the energy?

Gravity is the energy, gravity drives the sun, the weather and all of life on earth! Perpetually for now at least!

Gravity can raise a mountain to impressive heights, cause tidal waves that demolish coastlines, cause volcanoes to erupt, yet cannot influence solutes inside a tree or indeed a human? Bullshit!
Title: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 14/11/2009 12:57:57
Gravity is not a major enhancing factor in some of those things.

Also, aren't you making the fallacy of false analogy?
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 14/11/2009 16:33:42
"Gravity is the energy, gravity drives the sun,"
Just plain wrong.
Learn some physics and maths then come back.
Title: How do Trees Really lift Water to their Leaves?
Post by: Madidus_Scientia on 14/11/2009 21:37:36
Gravity does not provide the energy?

Gravity is the energy, gravity drives the sun, the weather and all of life on earth! Perpetually for now at least!

Gravity can raise a mountain to impressive heights, cause tidal waves that demolish coastlines, cause volcanoes to erupt, yet cannot influence solutes inside a tree or indeed a human? Bullshit!

lol
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/11/2009 09:54:11
And all of you know what gravity is?

Please let me know at your earliest convenience as this problem has eluded the greatest minds and to this day still does!

Title: How do Trees Really lift Water to their Leaves?
Post by: _Stefan_ on 15/11/2009 10:07:26
Are you saying that you know better than the rest of us what gravity is and how it does and does not work?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/11/2009 10:25:09
The plates on the following paper show clearly the size of xylem and number of xylem in comparison to phloem. Tiny amount of return flow in the phloem = solvent dragging on all of the more dilute sap in the xylem, evaporation at the leaves reduces the volume of sap but increases the density of the sap and the denser sap moves down the tiny by comparison phloem vessels.

Experiments with different diameter tubes has shown this to be worth considering.

Using an inverted U tube with 3 tubes one of which contained a small amount of coloured salt solution added at the upper part where the tubes were joined with a T junction, the salt solution moved down as expected and the salt free water in the other two tubes moved up, caused by solvent dragging on all of the water molecules.

In the case of the tree, the narrowing of the xylem vessels in the canopy compared to the xylem vessels in the trunk and branches affords a method of extruding the large volume of water shedding off the majority to evaporation and returning the solutes down the phloem vessels.

The paper also relates to the problem with addressing constant cavitations known to take place and also known to refill and repair the cavitations. The cohesion tension theory relies on root pressure for this, yet the rattan does not exhibit root pressure.

http://www.amjbot.org/cgi/reprint/89/2/196.pdf
American Journal of Botany 89(2): 196–202. 2002.
XYLEM OF RATTANS: VESSEL DIMENSIONS IN
CLIMBING PALMS1
JACK B. FISHER,2,3,5 HUGH T. W. TAN,4 AND LESLIE P. L. TOH4
environmental factors. During periods of limited rainfall, rattans
and other lianas can experience severe water stress. At
such times, both stomatal closure and stem water storage
would aid survival. In other lianas, water-storing tubers or succulence
of stems and leaves are common (Fisher and Ewers,
1991). Rattans lack tuberous roots and their narrow stems have
a small proportion of parenchyma that could function in water
storage. However, their long stems with a relatively large volume
of water in wide vessels represent a significant water reservoir
that would become available if cavitation of vessels
occurred during periods of extreme water stress (Holbrook,
1995). If cavitation of wide vessels does play a role in water
supply during draught periods, then the question of vessel refilling
must be addressed. Further studies should also focus on
the water capacity of rattan stems compared to nearby nonclimbing
palms, as well as their relative degrees of stomatal
control.
At present, we have no information on production of embolisms
in rattan xylem. Yet the low percentage of nonfunctional
vascular bundles in old stems suggests either a lack of
vessel cavitation or a mechanism for refilling vessels (and tracheids).
Other lianas have root pressure that is sufficient to
refill air-filled xylem, as in Vitis (Sperry et al., 1987), or to
decrease xylem tension and thus assist in removal of embolisms
(Fisher et al., 1997). In a nonclimbing palm, Sperry
(1986) found that embolisms were dissolved when xylem pressure
potential approached that of the atmosphere during periods
of rain. When stem bases of cultivated species of Calamus,
Daemonorops, and Desmoncus (a climbing nonrattan palm)
were cut at dawn during rainy periods, no exudation appeared,
thus indicating no root pressure (Fisher et al., 1997); however,
there was an indication of root pressure in one species of Calamus
cultivated in a mountainous rainforest. We suggest that
future measurements for possible root pressure are needed to
better understand water conduction for rattans growing in natural
environments.


environmental factors. During periods of limited rainfall, rattans
and other lianas can experience severe water stress. At
such times, both stomatal closure and stem water storage
would aid survival. In other lianas, water-storing tubers or succulence
of stems and leaves are common (Fisher and Ewers,
1991). Rattans lack tuberous roots and their narrow stems have
a small proportion of parenchyma that could function in water
storage. However, their long stems with a relatively large volume
of water in wide vessels represent a significant water reservoir
that would become available if cavitation of vessels
occurred during periods of extreme water stress (Holbrook,
1995). If cavitation of wide vessels does play a role in water
supply during draught periods, then the question of vessel refilling
must be addressed. Further studies should also focus on
the water capacity of rattan stems compared to nearby nonclimbing
palms, as well as their relative degrees of stomatal
control.
At present, we have no information on production of embolisms
in rattan xylem. Yet the low percentage of nonfunctional
vascular bundles in old stems suggests either a lack of
vessel cavitation or a mechanism for refilling vessels (and tracheids).
Other lianas have root pressure that is sufficient to
refill air-filled xylem, as in Vitis (Sperry et al., 1987), or to
decrease xylem tension and thus assist in removal of embolisms
(Fisher et al., 1997). In a nonclimbing palm, Sperry
(1986) found that embolisms were dissolved when xylem pressure
potential approached that of the atmosphere during periods
of rain. When stem bases of cultivated species of Calamus,
Daemonorops, and Desmoncus (a climbing nonrattan palm)
were cut at dawn during rainy periods, no exudation appeared,
thus indicating no root pressure (Fisher et al., 1997); however,
there was an indication of root pressure in one species of Calamus
cultivated in a mountainous rainforest. We suggest that
future measurements for possible root pressure are needed to
better understand water conduction for rattans growing in natural
environments.
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 15/11/2009 10:48:48
And all of you know what gravity is?

Please let me know at your earliest convenience as this problem has eluded the greatest minds and to this day still does!


No, but I do know some of it's properties.
For exaple;
It is the force that holds me down on the planet.
It isn't responsible for the heat from the sun
It doesn't push water up trees.
It doesn't drive all life on earth.

The world's great scientists mighht not understand it fully but, unlike you, they know what not to atribute to it.
Why dd you post that rubbish?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 15/11/2009 10:52:02
Gravity is what drives the sun! therefore gravity is responsible for the heat from the sun. No gravity = no sun No gravity = no BC and no earth to stand on! No gravity = nothing
Title: How do Trees Really lift Water to their Leaves?
Post by: Madidus_Scientia on 15/11/2009 11:57:20
Gravity is a force, not energy.
Title: How do Trees Really lift Water to their Leaves?
Post by: rosy on 15/11/2009 13:09:37
Hehe.

Ok, now I'm laughing. We're in real making-stuff-up territory now.

Sure the sun wouldn't be able to exist without gravity, because the matter wouldn't be concentrated in one place... but to say that gravity drives the sun is just ludicrous. What "drives" the sun (in the sense of providing the actual energy) is nuclear fusion. Nuclear fusion is not, repeat not, driven by gravity.
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 15/11/2009 14:22:18
"Gravity is what drives the sun!"
Still just plain wrong.
It's still time for you to learn some physics and maths.
Why did you post that rubbish?
Why don't you listen?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 18/11/2009 19:28:19
Hehe.

Ok, now I'm laughing. We're in real making-stuff-up territory now.

Sure the sun wouldn't be able to exist without gravity, because the matter wouldn't be concentrated in one place... but to say that gravity drives the sun is just ludicrous. What "drives" the sun (in the sense of providing the actual energy) is nuclear fusion. Nuclear fusion is not, repeat not, driven by gravity.
Where does the immense pressure come from that forces the atoms together to create fusion?
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 18/11/2009 20:45:47
Who cares?
If it were not for fusion all you would get was squashed gas.

Saying the sun is driven by gravity is like saying my central heating runs on a match.
OK, without a match to light the pilot light, the heating wouldn't work.
But it's still gas that heats my house.

It's still time for you to learn some physics and maths.
Why did you post that rubbish?
Why don't you listen?
 

Title: How do Trees Really lift Water to their Leaves?
Post by: Madidus_Scientia on 11/12/2009 19:47:27
I don't think you understand the gravity of the situation
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 21/03/2010 10:03:04
Titre du document / Document title
Osmosis and solute-solvent drag : Fluid transport and fluid exchange in animals and plants
Auteur(s) / Author(s)
HAMMEL H. T. ; SCHLEGEL Whitney M. ;
Résumé / Abstract
In 1903, George Hulett explained how solute alters water in an aqueous solution to lower the vapor pressure of its water. Hulett also explained how the same altered water causes osmosis and osmotic pressure when the solution is separated from liquid water by a membrane permeable to the water only. Hulett recognized that the solute molecules diffuse toward all boundaries of the solution containing the solute. Solute diffusion is stopped at all boundaries, at an open-unopposed surface of the solution, at a semipermeable membrane, at a container wall, or at the boundary of a solid or gaseous inclusion surrounded by solution but not dissolved in it. At each boundary of the solution, the solute molecules are reflected, they change momentum, and the change of momentum of all reflected molecules is a pressure, a solute pressure (i.e., a force on a unit area of reflecting boundary). When a boundary of the solution is open and unopposed, the solute pressure alters the internal tension in the force bonding the water in its liquid phase, namely, the hydrogen bond. All altered properties of the water in the solution are explained by the altered internal tension of the water in the solution. We acclaim Hulett's explanation of osmosis, osmotic pressure, and lowering of the vapor pressure of water in an aqueous solution. His explanation is self-evident. It is the necessary, sufficient, and inescapable explanation of all altered properties of the water in the solution relative to the same property of pure liquid water at the same externally applied pressure and the same temperature. We extend Hulett's explanation of osmosis to include the osmotic effects of solute diffusing through solvent and dragging on the solvent through which it diffuses. Therein lies the explanations of (1) the extravasation from and return of interstitial fluid to capillaries, (2) the return of luminal fluid in the proximal and distal convoluted tubules of a kidney nephron to their peritubular capillaries, (3) the return of interstitial fluid to the vasa recta, (4) return of aqueous humor to the episcleral veins, and (5) flow of phloem from source to sink in higher plants and many more examples of fluid transport and fluid exchange in animal and plant physiology. When a membrane is permeable to water only and when it separates differing aqueous solutions, the flow of water is from the solution with the lower osmotic pressure to the solution with the higher osmotic pressure. On the contrary, when no diffusion barrier separates differing parts of an aqueous solution, fluid may flow from the part with the higher osmotic pressure to the part with the lower osmotic pressure because the solute molecules diffuse toward their lower concentration and they drag on the water through which they diffuse. This latter osmotic effect (diffusing solute dragging on solvent or counterosmosis) between differing parts of a solution has long been neglected and ignored when explaining fluid fluxes in plant and animal physiology. For two solutions separated by a semipermeable membrane, osmosis is the flow of its solvent from the solution with the lower solute concentration into the solution with the higher solute concentration. For two contiguous solutions not separated by a semipermeable membrane, counterosmosis is the flow of solution with the higher solute concentration toward the solution with the lower solute concentration.
Revue / Journal Title
Cell biochemistry and biophysics   ISSN 1085-9195   CODEN CBBIFV 
Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 21/03/2010 21:47:08
So?
Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 19/04/2010 17:54:23

Experiment showing solvent drag and solute density applied tension to water filled vertically suspended silicone tubing.

Title: How do Trees Really lift Water to their Leaves?
Post by: Bored chemist on 19/04/2010 18:19:58
The experiment shows that salt water is denser than fresh water.
This bloke
http://en.wikipedia.org/wiki/Samuel_Plimsoll
made use of the fact a while ago; but it wasn't exactly news then.

Incidentally, silicon is what chips are made from; silicone is used to make that sort of tubing and huge boobs.
The walls of that tubing are more or less elastic so it's a poor model for things like blood vessels which have muscular walls.

Essentially, as far as I can see, all you have done here is play with coloured water.
Title: How do Trees Really lift Water to their Leaves?
Post by: Tritalon on 16/08/2010 21:00:32
Hello.

I have wondered what raises the water in plants. This video:
explains that driving force is transpiration, a process in which water diffuses from stomata into the atmosphere.

What exactly pulls the molecules of water into the air?
Title: How do Trees Really lift Water to their Leaves?
Post by: Agefive on 18/09/2010 06:49:49
I was sitting on my porch watching the trees sway in a gentle wind and thought to myself "how do those trees get so much water up to their leaves.  Then it came to me as I thought that a tree isn't a static object like a rock.  It is constantly moving as it sways to and fro.  I thought to my school days and the venous return theory based on one way valves in the veins which squirt the blood up to the heart through movement of muscles, not pure pressure.  So it dawned on me, why can't trees use the same technique?  I love my porch.
Title: How do Trees Really lift Water to their Leaves?
Post by: valachus on 10/10/2010 12:47:53
Surely if gravitation is not a primary component of plant growth and implicitly of sap dynamics, then growing plants aboard the ISS would be easy, or - rather - even easier than on Mother Earth. However this obviously incompetent dude says it was more complicated than it seemed back home: http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles13.html

Title: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 24/11/2011 09:38:57
Interesting footage from BBC Frozen planet showing density flow in the Antarctic ocean.

Well worth viewing.

Valachus

Thank you for the link and for your comment.

Agefive

The swaying of branches and the movement of leaves could well play an important roll in the movement of sap. I have applied the density flow to the vascular and arterial systems and used it to great effect with Inclined Bed Therapy. Thanks for your comment.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 25/12/2011 11:31:04
Siphon in a vacuum proves atmospheric pressure irrelevant to siphon effect.
Title: Re: How do Trees Really lift Water to their Leaves?
Post by: Andrew K Fletcher on 17/07/2014 08:36:54
https://www.youtube.com/watch?v=x68PLE8MXJE (https://www.youtube.com/watch?v=x68PLE8MXJE)

Radio Interview with Patrick Timpone on One Radio Network

20 years ago Andrew made a phenomenal discovery in circulation and how gravity acts upon fluid density changes that take place in all fluids where water is evaporated. In trees (Where this theory began) evaporation from the leaves alters the density of sap. In the body, the warm lungs and airways provide the same density changes in the blood and other fluids. It was not long before it became obvious that posture was incredibly more important than anyone could imagine. To make use of these density changes and allow them to assist the circulation all we needed to do was to manage our posture.
This was a Eureka moment of such magnitude it went off the scale for Andrew and instantly gave birth to Inclined Bed Therapy.
Show Highlights:
-Andrew explains how learning about how trees uptake water led him to understand the benefits of inclined bed therapy