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Energy production mechanism using capillary action

  1. Feb 3, 2014 #1
    We know that water rises in a glass capillary owing to the surface tension phenomenon. If we make an arrangement as shown in the attachment, (read Water instead of mercury in the attachment, I got confused there) & do the following procedure.
    The valve at the bottom is open, & the one at the top is closed.
    1) When the water rises, close the valve at the bottom.
    2) Then open the valve at the top.
    The water should come out from the branch & flow downwards. We put a collector flask just at the opening (not shown in the drawing), & put a set of similar arrangements above that flask.
    With the help of large number of capillaries & levels we should be able to rise significant amount of water at a particular height, store it there. Then use the potential energy of stored water to drive a turbine ( similar to hydro turbines),& generate electricity.
    Is this possible?
    If not Why?

    Attached Files:

    Last edited: Feb 3, 2014
  2. jcsd
  3. Feb 4, 2014 #2


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    Gold Member

    You are assuming, but probably for the wrong reasons.

    If the branch has a smaller diameter than the vertical tube, the radius of curvature of the water meniscus in the branch tube would be smaller than that of the vertical tube producing some capillary flow in the branch, but only to the point where the surface tension of the water at the exit would prevent the water from exiting. If the branch was of larger diameter, then either the meniscus of the vertical tube would only rise to the level of the branch, or if it did rise higher, the radius of curvature of the vertical tube meniscus being less than the branch, the tendency would be for the capillary action to be towards the vertical tube.
  4. Feb 7, 2014 #3

    If in the first case, when the diameter of branch is smaller than the vertical tube, the branch is made of different material altogether, but the valve is made of glass, still water won't come out? Is this because the outer pressure is greater than that would be due to its own weight?
  5. Feb 7, 2014 #4


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    Science Advisor

    Perpetual motion machines are impossible in reality because they break the law of conservation of energy. Energy cannot flow perpetually away from one point, without some reverse flow.

    If a hypothetical cycle can be arranged to release more energy than it consumes, then that is a perpetual motion machine.
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