Re: capillary effect

[Brian Whatcott <betwys@SBCGLOBAL.NET>]

At 11:45 AM 5/31/2003 -0400, you wrote:
> I have seen capillary tubes narrow enough to draw water
> to a hight above 1 cm. Suppose that such tube is inserted
> into water vertically and that only 0.5 cm is sticking out.
> One might imagine that water flows continuously upward
> in such tube. One can also imagine a tiny water wheel
> working continuously, next to the tube.
>
> Would this be a perpetual motion machine of the first kind
> or of the second kind? I know that this will not happen. But
> why not? Suppose that the easy answer "this would conflict
> with laws of thermodynamics" is not acceptable.
> Ludwik Kowalski


A fair question: why not?
I will attempt an answer.  Suppose that water rises at a
glass surface whose curvature is sufficiently pronounced
until the capillary force lifting the water thread is
balanced by the weight of the excess water column.
 If this curvature diminishes while there is still an
unbalanced lifting force, so does the motive force.

And at a top or side aperture, the  curvature of which I speak
falls to planarity. The water surface goes no further.

If one substitutes the concept of electric force, for capillary
force in this paragraph, then it might serve to explain the
reason that water dielectric shrinks from edges and holes
though otherwise there would be sufficient force to motivate
 further water lift.

Brian Whatcott     Altus OK