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Where Does The Energy Come From ?


deschoe

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As you can see in these following videos, capillaries are able to suck  away little waterhills in the surrounding areas of floaters, so that a floater in a capillary rises more than a floater outside a capillary.

For this you can create a circulation between the two floaters, that creates energy, but the question is, where does this energy come from ?
 
here is the 111 sec version :
 


 
and here the detailed explanation :
 

 
Please let me know, why do you think this is compatible with energy conservation as far ? Edited by deschoe
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As you can see in these following videos, capillaries are able to suck  away little waterhills in the surrounding areas of floaters, so that a floater in a capillary rises more than a floater outside a capillary.
For this you can create a circulation between the two floaters, that creates energy, but the question is, where does this energy come from ?
 
here is the 111 sec version :
 
 
and here the detailed explanation :
 
 
Please let me know, why do you think this is compatible with energy conservation as far ?

 

 

The phenomenon of capillary rise is certainly compatible with conservation of energy - as is everything apart from some obscure short-term quantum uncertainty effects (from which no energy can be extracted).

 

What is not correct is the assumption that one can set up a circulation, as you put it. That would violate conservation of energy and is thus, ipso facto, quite obviously wrong. However I have not, and do not intend to, waste my time watching YouTube videos about this.

 

Perpetual motion cranks habitually set up artificial scenarios that exceed their grasp of physics and which they are consequently unable to analyse correctly. That will be what is happening here.

Edited by exchemist
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The phenomenon of capillary rise is certainly compatible with conservation of energy - as is everything apart from some obscure short-term quantum uncertainty effects (from which no energy can be extracted).

 

What is not correct is the assumption that one can set up a circulation, as you put it. That would violate conservation of energy and is thus, ipso facto, quite obviously wrong. However I have not, and do not intend to, waste my time watching YouTube videos about this.

 

Perpetual motion cranks habitually set up artificial scenarios that exceed their grasp of physics and which they are consequently unable to analyse correctly. That will be what is happening here.

 

Hmmmm. I am not sure I agree entirely with you. Certainly, COE must be adhered to. The fluid in the capillary tube gains PE as it rises, and the fluid in the source loses PE as its level lowers conserving energy. However, I see no problem with COE if the fluid in the capillary were to overflow and return to the reservoir, setting up circulation, As Long As the falling water does no work on anything and just returns to the source. I suppose there would have to be no air resistance either, or it would be doing work on the air. But, theoretically, I think such a circulation is possible if there are no losses.. Hmmm, but I agree it does sound like PM.

Where am I going wrong?

Edited by OceanBreeze
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Hmmmm. I am not sure I agree entirely with you. Certainly, COE must be adhered to. The fluid in the capillary tube gains PE as it rises, and the fluid in the source loses PE as its level lowers conserving energy. However, I see no problem with COE if the fluid in the capillary were to overflow and return to the reservoir, setting up circulation, As Long As the falling water does no work on anything and just returns to the source. I suppose there would have to be no air resistance either, or it would be doing work on the air. But, theoretically, I think such a circulation is possible if there are no losses.. Hmmm, but I agree it does sound like PM.

Where am I going wrong?

 

 

Never mind. It would not wok in a vacuum and if it is not in a vacuum it would be doing work on the air, so there would be losses and as exchemist said, the circulation cannot happen.

 

I am back at sea, in the Andaman at the moment .. .eat your hearts out you landlubbers!

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Hmmmm. I am not sure I agree entirely with you. Certainly, COE must be adhered to. The fluid in the capillary tube gains PE as it rises, and the fluid in the source loses PE as its level lowers conserving energy. However, I see no problem with COE if the fluid in the capillary were to overflow and return to the reservoir, setting up circulation, As Long As the falling water does no work on anything and just returns to the source. I suppose there would have to be no air resistance either, or it would be doing work on the air. But, theoretically, I think such a circulation is possible if there are no losses.. Hmmm, but I agree it does sound like PM.

Where am I going wrong?

Well I haven't seen the videos but I suspect where you may err is in falling for the idea that capillary action can cause fluid to fountain out of the top. It can't.

 

Capillary action results from the chemical affinity of, say, glass for, say, water. The polar water molecules are attracted to the polar oxygen atoms in the glass and that is why water rises up a glass capillary. Once the water gets to the top of the tube, the attractive force no longer acts upward but purely sideways. And so the water stops rising.

 

There is no circulation at all.

 

From the CoE viewpoint, any such circulation would be a violation, since the flow would dissipate heat at various points in the cycle. But it wouldn't come out of the top of the tube in the first place anyway.

Edited by exchemist
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Addendum: I'm pretty sure I know who this poster is, actually. He has come up with hare-brained ideas for perptual motion due to surface tension before. I have engaged with him on other forums. He does not understand surface tension, basically.  

 

As I said earlier, it's the usual thing: devise a physical scenario beyond your capacity to analyse correctly, make wrong deductions about it, and, hey presto, you have just proved all of physics -  and Emmy Noether - wrong.

 

Not. :)

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thats funny. why dont you want to watch the video, are you afraid to loose your episteme ? so if you like to discuss herein, please have a look at the upper video, long versin. thank you.

We've been through this - elsewhere. There are 3 reasons:

 

1) YouTube is full of sh1t: many videos are so badly presented as to be impossible to understand properly, and some are even faked,

2) videos are generally an inefficient way to communicate ideas. The written word - accompanied by diagrams where necessary - is far superior. I do not like to waste my time. 

3) a discussion forum is for discussion, i.e. in the words of the contributors. We can all watch videos in our own time, if we choose to.

 

But in any case, I've given my reasons already as to why this won't work. If you are serious, you will try to address my explanation as to why capillary action will not cause liquid to emerge spontaneously from the top of a capillary.

Edited by exchemist
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lol!  That is not endless circulation. Someone is using two sets of tweezers and putting in much more energy than any put out by the capillary action. 

Quite. Capillary action can only lift something while the attractive force between the liquid surface and the capillary is near vertical. As the liquid surface approaches the top of the capillary, the attraction starts to act increasingly obliquely, since there is no more capillary above. The limit to the rise will be when the surface meniscus reaches the top of the tube. At that point, it will stop. The liquid surface will still have the meniscus appearance, i.e. with a depression in the centre. At the edges, the angle of contact will be such that the remaining vertical component of force will just balance the weight of the liquid drawn up the tube - it will be at equilibrium. Of course if the tube is long enough the force will be insufficient to pull liquid right to the top, and in fact one finds the degree of capillary rise can be calculated from the dimensions of the tube, the surface tension and the angle of contact of the surface. So the liquid can only get close to the top in a short tube. It can never come out of the top - if the only lifting force is capillary action.

 

The error in the thinking of our poster seems due to a failure to understand what causes capillary rise: it is a force exerted only at the surface of the liquid, not within the body of it.

 

But I'll bet he does not address this in his responses. :)     

Edited by exchemist
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ok maybe you will be surprised, but I guess you are quite right with your statements, but we are a talking about the negative pressure in a capillary, and it seems you overlooked this, so watch the long version video until you answer again  and now I bet you do not address this in your next  responses

Edited by deschoe
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ok maby you do will be surprised, but I guess you are quite right with your statements, but we are a talking about the negative pressure in a capillary, and it seems you overlooked this, so watch the long version video until you answer again  and now I bet you do not address this in your next  responses

If I am right with my statements then there is no circulation, no perpetual motion and no violation of conservation of energy. Also if I am right with my statements, negative pressure does not need to be considered, since my explanation makes no mention of this.

 

The main thing is it seems we are now agreed about the answer to the question originally posed in this thread. Good.

 

I shall indeed not be watching the YouTube video. So you win your bet on that  :)

 

If however you can explain in your own words why you think -ve pressure is important I will be happy to comment on what you have to say. For the time being, the way I would comment on this is that, immediately under the liquid surface within the capillary, the pressure is slightly below atmospheric. This is because of the upward force due to surface tension that I have been talking about, which partially offsets the air pressure above the meniscus. The rise of liquid up the tube can be seen as due to this pressure reduction. In a tall tube, the height of liquid that rises up the tube is a measure of the degree of pressure reduction: the rise will stop when the pressure reduction at the top is exactly counteracted by the extra weight of water lifted up the tube. (In a very short tube this may not be true, as you may then find the meniscus reaches the top and then stops due to the change in direction of the previously upward force into a predominantly lateral one, as I described earlier.)  

 

So you can consider this problem from the viewpoint of pressure if you like, though it is not necessary to do so, as shown by my earlier explanation of it.

Edited by exchemist
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watch the video, its high quality, and was made to avoid complicated explanationes .

 

First, there are too many close - ups.  I would prefer if they panned out so you could see what was at the other ends of the rods.  Second they relied heavily on animation because what they animated just doesn't happen.  In reality, you would be adding much, much more energy into the system than you could ever extract out of it.  Try it in your kitchen and find out for yourself if you need to.

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