How do Trees Really lift Water to their Leaves?

Lyner:
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.

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 surmising what you think must be happening?

By the way cloud Cuckoo land is way above 24 meters vertically. And unlike the cohesion tension theory you et al adhere to, it does not suck.

Lyner:

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.

@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.

Lyner:

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.
« Last Edit: 05/11/2008 19:27:47 by sophiecentaur »

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?

Lyner:
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 School kids 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?

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?

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.

Lyner:
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.