| Topic: |
Science > Physics |
| User: |
"Seth" |
| Date: |
18 Nov 2004 10:12:08 PM |
| Object: |
maxwell's demon refrigerator |
Hi everybody -
I think I've come up with a variant of Maxwell's demon (probably not
originally, but I've never heard of it), and though it's obviously
impossible, I'm having a hard time figuring out exactly why. So here
it is: you have a box with a gas in it, and embedded in the walls are
nano-scale seesaw-like things that when you push in on one side, the
other side goes out, and work is also extracted. I imagine a molecule
of the gas hitting one side of the seesaw, thereby pushing the other
side out, and also doing some work on something attached to the seesaw
to generate a current or something, and then bouncing off the seesaw
with a lower speed than it impacted with. The key is that the seesaw
is so small, when one side is being hit by a molecule, the other side
probably isn't, so the gas pressure doesn't produce a balanced force
the way it would on a macro-scale seesaw. If two molecules happen to
hit both sides of the seesaw at the same time, no problem, the seesaw
flexes and throws the molecules back with the same speed they impacted
with.
I also imagine the box to be well insulated from its surroundings, so
that the total effect is that the temperature and pressure inside the
box drop with respect to its surroundings while a current is induced
in a pair of wires going into the box, until some equilibrium is
reached. You see the problem.
The only reason I would suspect this to be something different than
Maxwell's demon is that I don't see it violating conservation of
energy - the internal energy of the contained gas is lowered. To me,
it just seems to be violating the second law in a big way, while
leaving the first alone. But I'm probably wrong about that, too. :o)
Thanks for any help,
Seth
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| User: "Uncle Al" |
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| Title: Re: maxwell's demon refrigerator |
19 Nov 2004 10:36:27 AM |
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Seth wrote:
Hi everybody -
I think I've come up with a variant of Maxwell's demon (probably not
originally, but I've never heard of it), and though it's obviously
impossible, I'm having a hard time figuring out exactly why. So here
it is: you have a box with a gas in it, and embedded in the walls are
nano-scale seesaw-like things that when you push in on one side, the
other side goes out,
[snip crap]
Thermal agitation, kT, of the seesaw, teeter-totter, dandle, dandle
board, teedle board, teeter, teeterboard, teeter-totter, tilt1,
tilting board. TILT.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
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