Thought Experiment - Work From Heat

Originally posted by AThousandYoung
Is it possible to make a keyboard with keys as small as the molecules in air?

If so, couldn't one use such a keyboard to generate energy from air pressure alone? As one air molecule hits a key, it applies energy to it, which could be stored. Instead of the air pressure hitting one solid surface it hits many tiny surfaces which means one part can b ...[text shortened]... pressed right next to it like keys on a keyboard.

Sonhouse? Anyone else? What do you think?

It would violate the Second Law just like any other perpetual motion machine.

Originally posted by AThousandYoung
Is it possible to make a keyboard with keys as small as the molecules in air?

If so, couldn't one use such a keyboard to generate energy from air pressure alone? As one air molecule hits a key, it applies energy to it, which could be stored. Instead of the air pressure hitting one solid surface it hits many tiny surfaces which means one part can b ...[text shortened]... pressed right next to it like keys on a keyboard.

Sonhouse? Anyone else? What do you think?

In thermodynamic equilibrium, there would be equally as much energy transferred from the "keys" to the air.

If you define your "keyboard" in such a way that this is not possible, then the keyboard itself is not possible.

Originally posted by AThousandYoung
Is it possible to make a keyboard with keys as small as the molecules in air?

If so, couldn't one use such a keyboard to generate energy from air pressure alone? As one air molecule hits a key, it applies energy to it, which could be stored. Instead of the air pressure hitting one solid surface it hits many tiny surfaces which means one part can b ...[text shortened]... pressed right next to it like keys on a keyboard.

Sonhouse? Anyone else? What do you think?

You could do this, but you have to transfer energy away from the keyboard. The obvious way of doing this is to connect the keyboard to a heat sink, in which case your magic keyboard is basically a high tech version of leaving the fridge door open. To see if you get a net energy output you can do an experiment and leave your fridge door open and see if your electricity bill goes down.

Originally posted by AThousandYoung
Is it possible to make a keyboard with keys as small as the molecules in air?

If so, couldn't one use such a keyboard to generate energy from air pressure alone? As one air molecule hits a key, it applies energy to it, which could be stored. Instead of the air pressure hitting one solid surface it hits many tiny surfaces which means one part can b ...[text shortened]... pressed right next to it like keys on a keyboard.

Sonhouse? Anyone else? What do you think?

I think if you could build such a device it would extract energy from the air all right but then the air would get colder and there would be an end to it, some point at which air could not transfer energy anymore because it would be too cold. It might be a way to make a futuristic refrigerator maybe, you would have to introduce fresh air but if you have a closed system like the planet Earth, you would eventually run out of energy, it sounds like what would happen if you could have a 4000 mile deep well which could stay strong at the center of the earth and you could suck heat out of it and use it on the surface. Eventually the core would freeze and that would be the end of that trick and the end of continental plate movement and the end of Earth's magnetic field.

There is a design that works for a small nuclear battery, a source of radiation, and a flexible membrane that turns the radiation to electrons which accumulate on the membrane and an unmovable electrode. When the electron cloud in the membrane builds up to a certain point it bends the membrane to short out against the electrode and sends a pulse of energy to charge up a capacitor and the cycle starts again. If you have thousands of the tiny electrodes near a radiation source they all end up bending and discharging giving a steady but small amount of electricity for maybe 30 years.

I would think your nanokeys would start getting hot and end up transferring energy back to the air molecules impinging on the key. What is to prevent the key from striking the next air molecule in line and transferring its energy right back into the system?

What if, instead, you had the nanokey attached to a piezo-electric generator, like those sonalerts that beep when the computer thinks you made a mistake or something. But with that arrangement you would not need keys, just nanosized piezoelectric buds the size of air molecules. Maybe the air molecules impinging on the buds would cause a small squirt of electrons kind of like the nuclear battery idea.
If so, it would still end up cooling the air and thus would not be a perpetual motion machine, it would end up the same way, cooling off the air so you would be feeding warm air and exiting cooler air which if mixed with the incoming air would start a cycle of cooling the whole supply of air. You can't have a big enough box for that to start happening at some point. I assume the piezo buds would have to have a vacuum behind each bud somehow so there would be a one way whacking of the buds. If they were just in open air, the top of the buds would get hit with the same energy as the bottom so generate no net power. But you can't get around the problem that it would be cooling the very air you use to get the power so it would not be a permanent source of energy, only a temporary one.

It sounds like a variation of Maxwell's Demon, where a little guy see's air molecules hit a door and the demon only lets the hotter of air molecules through the door and thus builds up a temperature difference from one side of the wall to the other which could generate power if it didn't fly against the second law of thermodynamics.

Originally posted by sonhouse
It might be a way to make a futuristic refrigerator maybe, you would have to introduce fresh air but if you have a closed system like the planet Earth, you would eventually run out of energy, it sounds like what would happen if you could have a 4000 mile deep well which could stay strong at the center of the earth and you could suck heat out of it and use i ...[text shortened]... of that trick and the end of continental plate movement and the end of Earth's magnetic field.

If that were true it would be an extremely useful device.