The Naked Scientists

The Naked Scientists Forum

Author Topic: How do Trees Really lift Water to their Leaves?  (Read 244922 times)

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8665
  • Thanked: 42 times
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #175 on: 26/10/2008 14:38:37 »
Fascinating, but I'd sooner see you answer Sophie's question.
 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #176 on: 26/10/2008 22:42:02 »
I think it would be water from a stone.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #177 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.
« Last Edit: 27/10/2008 10:15:55 by Andrew K Fletcher »
 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #178 on: 27/10/2008 10:39:13 »
And what does this pupil know?
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #179 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 Galileoís 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 Ė depending on the species and ecophysiological context Ė 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

 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #180 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?
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8665
  • Thanked: 42 times
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #181 on: 27/10/2008 18:57:46 »
Fascinating Andrew,
but I'd sooner see you answer Sophie's question
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #182 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
« Last Edit: 28/10/2008 11:01:22 by Andrew K Fletcher »
 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #183 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.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #184 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.   

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.
 

Offline BenV

  • Neilep Level Member
  • ******
  • Posts: 1503
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #185 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...
 

Offline rosy

  • Neilep Level Member
  • ******
  • Posts: 1018
  • Chemistry
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #186 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.
 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #187 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?
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #188 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 godís sake, itís 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 Fatherís bedside, have shown the results to the staff and doctors at Russellís 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 Russellís 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.
 

Offline BenV

  • Neilep Level Member
  • ******
  • Posts: 1503
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #189 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)
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8665
  • Thanked: 42 times
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #190 on: 28/10/2008 18:06:59 »
Fascinating Andrew,
but I'd sooner see you answer Sophie's question
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #191 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.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #192 on: 28/10/2008 19:59:40 »

IBT is very good for Alzheimerís 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

 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #193 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.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #194 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 donít 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 Sophieís 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 canít 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?




 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #195 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?
« Last Edit: 28/10/2008 21:49:09 by sophiecentaur »
 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #196 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.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #197 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.
 

Offline Andrew K Fletcher

  • Neilep Level Member
  • ******
  • Posts: 2331
  • KIS Keep It Simple
    • View Profile
Re: How do Trees Really lift Water to their Leaves?
« Reply #198 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 donít you. If you canít understand something then at least try it out and explain it better if you feel able to.

 

lyner

  • Guest
Re: How do Trees Really lift Water to their Leaves?
« Reply #199 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.
« Last Edit: 29/10/2008 09:03:50 by sophiecentaur »
 

The Naked Scientists Forum

Re: How do Trees Really lift Water to their Leaves?
« Reply #199 on: 28/10/2008 22:41:55 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length