Maxwell's Demon: An Energy Conversion Experiment

[ZapperZ]

I have a few questinons abut the cathodes in the tube.

If I understand them corectly they eject elecrons becouse of heat. But in vacuum tube thereis no air and the only way heat can be trensferd from the outside of the tube on to the cathodes is by infrared light. So it seams that they act a bit like the photoefect. So if I understan it the cathodes should slovley wear out and that would explein where the missing enthropy is.

Pleas corect me if I'm wrong.

I'll answer this for a generic cathode and not specificially for this particular experiment.

A thermionic cathode emit electrons via heating the cathode. You heat the cathode by passing current through it. So the fact that it is in vacuum is of no concern. In fact, in all of these cathodes, you want them to be in a vacuum or else electron transport is hindered.

A photocathode works using the photoelectric effect phenomena. There's no heating here. All you need are photons with energy larger than the cathode work function.

The cathodes in both setup do not exactly "wear out", because they are connected to ground i.e. they are typically grounded or connected in a closed circuit, so the electrons that left the surface are continually replenished. In a photocathode, especially, you definitely want it grounded because if you don't, you will have a build up of charges (charging effect) that will significantly alter the work function of the cathode.

Zz.

 

[LENIN]

Thanks for the explination, Zz.

I have qouit a hard time with this thing. It's hard to believe that the second law of thermodynamics is wrong.

 

[pervect]

Thanks for the explination, Zz.

I have qouit a hard time with this thing. It's hard to believe that the second law of thermodynamics is wrong.

Extremely hard. That's why I don't believe the claims that it is wrong.

 

[zoobyshoe]

Wait a minute, isn't a change in an object's direction of motion an acceleration? And, if so, this implies a force was applied (Newton's 2nd Law), which implies work was done on the electron, which implies an energy change.

I don't know how to analyse this situation with terminological rigor. The point I was trying to make, however clumsily, I think is still accurate, and that is that no energy is lost by the magnetic field and added to the electron during this interaction. The term "acceleration, I know, encompases deceleration, and a "change in energy" can refer to a drop in energy, as well as an increase. The electron can technically "accelerate" and experience a "change in energy" because of its interaction with the magnetic field and still end up with less than it started with.

My primary goal was to counter the notion a couple people seemed to have that a magnetic field represents "stored" energy that is depleted with each use, like a capacitor or battery. A magnetic field can't be used as a "power source" in that way at all.

If work is done on the electron in a technical sense it is only because the electron first did work on the magnetic field. I think this is like a hard ball bouncing off an elastic surface: the ball gives its energy to the surface which then gives it back to the ball.

If the magnetic field suffers an energy loss from this interaction, say at some quantum level (I have no idea if it does) then this is quite different from the phenomenon by which magnets lose their magnetism over time. A couple people seemed to think magnets lose their field strength by getting "used up" so to speak, with continued use, as if they contained a finite amount of energy that was withdrawn with each use, like money from a bank account. They thought this finite amount of energy was being put into them when they were magnetised. But magnets aren't analagous to storage batteries or capacitors.

 

[LENIN]

I just got tjis idea but I don't know if it's any good.
When I looked over tha plans I didn't find any grounding. So it seams that there is no new electorns in the curcit. The ones that are alredy in are trtensfering all the energy. But I think that some of them exit the sistem and that this electrons are the missing enthropy

 

[xyfu]

Originally posted by Lenin

I have quite a hard time with the thing. It's hard to believe that the second law of thermodynamics is wrong.

So far as mankind is informed, all practical processes result in the degeneration of energy. It is most common in everyday life that useful energy, once used, will be transformed into waste one. The reverse transformation, i.e., waste energy converts into useful one, has never been found till now. Hence, though energy is surely conserved in quantity, for every piece of energy that the nature granted us, we can use it once only. It cannot be used repeatedly.That is the second law of thermodynamics.

There were two opposite opinions about this law in the world of physics:

On one side, the representative is the prominent German physicist Rudolf Clausius who put forth in 1850 the second law of thermodynamics, and introduced in later the concept of entropy, declaring that the universe is doomed to go forward step by step to a final destination, the Heat Death. Then, no any useful energy left, only waste ones at a uniform low temperature.

Then we have James Clerk Maxwell, the most outstanding physicist of the nineteenth century, as the giant on the other side. He proposed that if we can see and interfere (or control) the motion of the individual molecules of a gas, which is initially at a uniform temperature and a uniform pressure, we will be able to renew the waste energy to useful one again, in contradiction to the second law of thermodynamics.

This is a major dispute in the history of physics. Which of the two opinions will win eventually?

Oh, we see that the dispute is still going on. Nevertheless, Maxwell’s molecules in a vessel (at certain temperature) are now replaced by thermal electrons in a vacuum tube.

Realization of Maxwell's Hypothesis http://www.arxiv.org/list/physics/0311104

 

[LENIN]

I have a question xyfu, that my not be of any importance but I'm wondering. For how long did you leave your tube in runing (aprox.)?

 

[xyfu]

An answer to Lenin


The instrument we used to measure the current, electrometer ZC43, was not of a very ideal quality. In most times, it can be kept in a stable state for about thirty minutes. During the stable peoriod, the current produced in our test could flow continuosly.

We know there is some better instrument, for example, KEITHLEY Model 6517. But it is too expensive, and we cannot afford for it.

We have failed many times in making the electronic tubes. and most of the money (our own money) was spent in making the tubes. So far, there is no financial support from any institute for the experiment.

But this is not a real problem. We can progress, though rather slowly.

 

[LENIN]

I hope you get some suport becouse this seams to be quit an iteresting experiment and alldo it may not work in contrdiction to the secon law I still believe it could be very useful. You should definately try to improve your tubes. I would love to see progres in this area.

 

[xyfu]

Dear Lenin,

Thank you for your kindness.

xyfu and ztfu

 

[what_are_electrons]

A couple of ideas that might help.

In my suggestions below, I am assuming that the flow of electricity in the device occurs while the fixed magnet is at rest and is not subject to any sort of vibration or motion.

Have you had a chance to perform this experiment in total darkness with no chance of any UV or visible light? This would probably eliminate most of the thoughts that there are photoelectric type effects at work.

Once the device is inside this light-free container, have you had the chance to change the temperature around just the device? Hopefully, all the other electronics can be maintained at a near constant temperature. Assuming you get a response to the heat only change, this would demonstrate that heat is the cause.

Since Heat is still an infrared type of photon energy, it might then be interesting to devise a cheap system to stop infrared photons from reaching the device while allowing various wavelengths of other light to reach the device, if such a system is possible.

Odd notes:
Alkali metals, such as Cs, are well known to drop the work function such that electrons can be freed. When Cs is made into an oxide, it probably is a better emitter. The Ag is interesting because Ag is well know for its sensitivity to light (eg photography and Surface Enhanced Raman Spectroscopy). Cs is also used in SIMS to enhance the production of fragments that might not otherwise be observed.

I'm just now wondering about Cu and its oxides because they are just above Ag in the periodic table and they are used as self-regenerating catalysts, but this may be true only in the presence of air.

These odd notes are just some thoughts that might stimulate your efforts to improve the output of the single unit if that's possible.

Good luck!

 

[xyfu]

Originally posted by Vince

Have you had a chance to perform this experiment in total darkness with no chance of any UV or visible light? This would probably eliminate most of the thoughts that there are photoelectric type effects at work.

Once the device is inside this light-free container, have you had the chance to change the temperature around just the device? Hopefully, all the other electronics can be maintained at a near constant temperature. Assuming you get a response to the heat only change, this would demonstrate that heat is the cause.

Our experiment was performed in total darkness. The electronic tube FX1 was enclosed in a copper box whose walls and top and bottom are all made of copper plates six millimeter in thickness. No any light or UV could enter the box and reach the tube.

We dared not to change the room temperature by an air conditioner, etc. Air conditioner will cause serious difference in temperature along the whole testing circuit, i.e., the circuit composed of tube FX1, the cable and the input resistance of the electrometer ZC43 (which is a load in the test). Such a difference in temperature along the circuit will result in Seebeck electric motive force and so on, which is terrible to our test. Ideal or very high quality constant-temperature box or constant-temperature room is very expensive for us. Common constant-temperature box or constant-temperature room is not qualified for the experiment.

Maybe we can do an experiment in the warm afternoon, and repeat the experiment in the cool midnight. The difference in temperature between day and night may be up to five or even ten degrees. In either case the temperature along the circuit can be kept constant finely.

Nevertheless, may be, the change in current due to such a change in temperature is not very obvious, and the sensibility of the electrometer ZC43 might also change slightly, and so on.

We have considered doing the test at different temperatures. Nevertheless, there were difficulties, and we stopped the effort. Anyway, just as you said, to get for the current a response to heat is very convincible. It is worth making efforts to try.

Thanks for your suggestion.