How do Trees Really lift Water to their Leaves?

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Offline Mr. Scientist

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Re: How do Trees Really lift Water to their Leaves?
« Reply #350 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: http://www.youtube.com/watch?v=sz9eddGw8vg

Video introduction to density flow on Youtube: http://www.youtube.com/watch?v=PVwSIeWMSkc

Video of a scaled down version of the Brixham Experiment on youtube: http://www.youtube.com/watch?v=FjWe6kLHcLU

Video of a simple experiment to show density flow in boiling sugar syrup. http://www.youtube.com/watch?v=187awfsgHoY


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


You could think of the leaves breathing the evaporation, but this is especially new to me...

I must read more of this thread.
http://www.youtube.com/watch?v=SZGcNx8nV8U

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٩๏̯͡๏۶

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Offline davlin47

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How do Trees Really lift Water to their Leaves?
« Reply #351 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
« Last Edit: 28/10/2009 17:03:37 by BenV »
newbielink:http://www.thenakedscientists.com/forum/ [nonactive]

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #352 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.
Science is continually evolving. Nothing is set in stone. Question everything and everyone. Always consider vested interests as a reason for miss-direction. But most of all explore and find answers that you are comfortable with

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Offline _Stefan_

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How do Trees Really lift Water to their Leaves?
« Reply #353 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?
Stefan
"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." -David Hume

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #354 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.
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Offline _Stefan_

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How do Trees Really lift Water to their Leaves?
« Reply #355 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 :)
Stefan
"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." -David Hume

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #356 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.      http://www.youtube.com/watch?v=PVwSIeWMSkc
2.   http://www.youtube.com/watch?v=FjWe6kLHcLU
3.   http://www.youtube.com/watch?v=sz9eddGw8vg


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
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Offline rosy

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How do Trees Really lift Water to their Leaves?
« Reply #357 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...

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Offline _Stefan_

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How do Trees Really lift Water to their Leaves?
« Reply #358 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?
Stefan
"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." -David Hume

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #359 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.
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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #360 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.

Science is continually evolving. Nothing is set in stone. Question everything and everyone. Always consider vested interests as a reason for miss-direction. But most of all explore and find answers that you are comfortable with

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Offline Bored chemist

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« Reply #361 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.
Please disregard all previous signatures.

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #362 on: 11/11/2009 09:32:45 »
Well go ahead and provide the maths then
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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #363 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!
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Offline BenV

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« Reply #364 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.

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Offline Bored chemist

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« Reply #365 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.
Please disregard all previous signatures.

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Offline Andrew K Fletcher

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How do Trees Really lift Water to their Leaves?
« Reply #366 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.
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Offline rosy

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« Reply #367 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).

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Offline Andrew K Fletcher

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« Reply #368 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?
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Offline rosy

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« Reply #369 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)

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Offline Bored chemist

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« Reply #370 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.
Please disregard all previous signatures.

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Offline rosy

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« Reply #371 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.

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Offline Andrew K Fletcher

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« Reply #372 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


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Offline rosy

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« Reply #373 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.

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« Reply #374 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.

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« Reply #375 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.

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« Reply #376 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?
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« Reply #377 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.


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Offline rosy

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« Reply #378 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?

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« Reply #379 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


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« Reply #380 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!
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Offline _Stefan_

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« Reply #381 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?
Stefan
"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." -David Hume

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« Reply #382 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.
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« Reply #383 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

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« Reply #384 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!

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« Reply #385 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?
Stefan
"No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact which it endeavors to establish." -David Hume

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« Reply #386 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.
« Last Edit: 15/11/2009 10:49:03 by Andrew K Fletcher »
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Offline Bored chemist

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« Reply #387 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?
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Offline Andrew K Fletcher

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« Reply #388 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
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Offline Madidus_Scientia

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« Reply #389 on: 15/11/2009 11:57:20 »
Gravity is a force, not energy.

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Offline rosy

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« Reply #390 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.
« Last Edit: 15/11/2009 16:19:26 by rosy »

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Offline Bored chemist

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« Reply #391 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?
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Offline Andrew K Fletcher

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« Reply #392 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?
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Offline Bored chemist

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« Reply #393 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?
 

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Offline Madidus_Scientia

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« Reply #394 on: 11/12/2009 19:47:27 »
I don't think you understand the gravity of the situation

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« Reply #395 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 
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« Reply #396 on: 21/03/2010 21:47:08 »
So?
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« Reply #397 on: 19/04/2010 17:54:23 »
http://www.youtube.com/watch?v=zNJHChtHklg

Experiment showing solvent drag and solute density applied tension to water filled vertically suspended silicone tubing.

« Last Edit: 24/04/2010 09:49:38 by Andrew K Fletcher »
Science is continually evolving. Nothing is set in stone. Question everything and everyone. Always consider vested interests as a reason for miss-direction. But most of all explore and find answers that you are comfortable with

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Offline Bored chemist

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How do Trees Really lift Water to their Leaves?
« Reply #398 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.
Please disregard all previous signatures.

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Offline Tritalon

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How do Trees Really lift Water to their Leaves?
« Reply #399 on: 16/08/2010 21:00:32 »
Hello.

I have wondered what raises the water in plants. This video:
newbielink:http://www.youtube.com/watch?v=At1BJJDcXhk [nonactive]
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?