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Re: Why does electrostatic attraction in water decrease?



"John S. Denker" wrote:

I wrote:
-- We could run a water-wheel using the water that leaks out of
the hole, and have a nice perpetual-motion machine.
...
In particular, repeat the experiment with liquid helium
instead of water. Cool it to a few millikelvin. Dielectric
effects will be essentially independent of temperature over
a wide range.

Pentcho Valev responded:

Intuition confronts the second law. One punches a hole in the wall of an open
vessel filled with water and expects the water to come out, but the water does
not come out because the the second law says no.

There is no reason to believe the 2nd law is involved.
The perpetual motion machine in question violates conservation
of energy, which is the first law.

Not if the water between the plates of the capacitor is lifted at the expense of
heat absorbed from the surroundings. Then, as you punch a hole in the plate and the
water comes out and falls back, the accumulated energy will be released. If you
harness the waterfall (outside the capacitor), you may obtain work. If not, the heat
will go back to the surroundings. Of course, this will hapen if the water comes out
through the hole. If the second law succeeds in stopping it, there is nothing to
talk about.



To repeat: The effect should be observable in 4He and should
be essentially independent of temperature over a wide range.

For the moment I don't see why we should replace the liquid meant by Panofsky (he
does not specify it) with liquid helium.



I see no reason to think the 2nd law is involved.

Didn't you say "perpetual motion machine" above?

I did. That does not imply that the 2nd law is involved.

Mythology people are afraid of. "Perpetuum mobile of the second kind"

My example is a p.m. of the first kind, not second kind.

... the second law is not even defined properly.

I'm sure you can find innumerable instances where the law is
misstated. That does not however preclude me and my friends
from understanding the intended meaning and from restating it
in more-precise terms.

I think one should be even more radical than you and your friends. For instance, I
don't see in the site below the classical definition of the entropy, dS = dQrev/T.
You may not like it for some reason, but it is the working definition e.g. in
traditional chemical thermodynamics. Curiously, Gibbs only dealt with chemical
systems in equilibrium, knowing that the application of this definition to a
non-equilibrium state is tantamount to an oxymoron. Then someone, encouraged by the
chaos in the field, found it suitable to apply this definition to chemical changes
distant from equilibrium. Just imagine: Qrev implies that the system passes through
a succession of EQUILIBRIUM states, and yet the state of the system is, by
definition, distant from equilibrium!

So is the situation with the second law. What is, for instance, ESF: Entropy is a
State Function? A version of the second law? What is END: Entropy Never Decreases?
Another version? You may accuse me of giving imperfect statements, but what is much
more important is to find the RELATION between ESF and END. Are they equivalent?
Some other subordination? Unrelated? What is their relation to the two Kelvin
versions from my previous posting? Which version is used e.g. in chemical
thermodynamics? Why does nobody offer a falsification test for the second law? Etc.
Etc.

Pentcho



http://www.monmouth.com/~jsd/physics/thermo-laws.htm#sec-second-law