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Maxwell’s Demon - An Energy Conversion Experiment in Contradiction to the Second Law

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xyfu
#37
Jun14-04, 11:35 AM
P: 16
Dear Zoobyshoe ,

Thank you a lot! Actually we published our former paper early in 1982. Everyone can find it in library.
ZapperZ
#38
Jun14-04, 12:02 PM
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Quote Quote by xyfu
We have found the real original papers listed by Mr. Olias and got their titles, authors and published dates. They are shown as follows:

1. http://www.sp.uconn.edu/~terry/images/anim/ETS.html
Animation of Electron transport in Mitochondria
copyright 1997. Thomas M. Terry, The University of Connecticut.

2. http://www.nature.com/nsu/020101/020101-1.html
New state of matter made
Physicists have created a patterned liquid.
3 January 2002
PHILIP BALL

They were published in 1997 and 2002, respectively. The former relates to bi-chemistry and latter relates to some new material. They have nothing to do with thermal electrons in a vacuum tube!

Our experiment was done during 1998 and 2001, we knew nothing about these two papers. We had got most ideas about our experiment in late 1970s, and we had a paper, which described almost all the ideas related, published in ENERGY CONVERSION AND MANAGEMENT in January 1982. The editor-in-chief of the journal, Dr. Jesse C. Denton, exchanged opinions with us many times. We also take it as one of references in the paper of Maxwell’s Demon - An Energy Conversion Experiment in Contradiction to the Second Law.

The following is the title, abstract etc of the paper published in 1982.


Energy Conversion and Management, Vol.22 pp.1 to 3 (1982)------

An Approach to Realize Maxwell’s Hypothesis
Xin Yong Fu
Department of Applied Physics, Jiao Tong University, Shanghai, China
(Received 29 January 1981)

Abstract “Maxwell’s demon”----the well known hypothesis put forward by J. C. Maxwell in 1871 has excited resonance and stormy discussion over and over among many physicists for more than a century, but never has it been realized. In this article we suggest an experiment where thermoelectrons emitted from two oxide cathodes in a specially devised vacuum tube are substituted for gas molecules in Maxwell’s vessel of two portions, while the application of a magnetic field to acting Lorentz force on the thermoelectrons offers the controlling service of the “demon”, so that electrons can only fly from one pole (A) to another (B) and a potential difference as well as an electric current can thus be gained. Through this experiment we could carry out Maxwell’s hypothesis and provide an example to break through Keivin’s formulation of the second law of thermodynamics.



Certainly, we are not so stupid to guess that Mr. Thomas M. Terry or Mr. Philip Ball has cloned our ideas.

Mr. Olias, we think you have insulted us, very impolitely.
1. Phillip Ball is an EDITOR of Nature. That link is a REVIEW of the paper that is cited at the END of the article. Read it again carefully. If you think that paper he is reviewing "cloned" your idea, then WRITE to Nature. Don't just slander the authors on here.

2. If you are really claiming that you have measured a system that demonstrate a Maxwell Demon, then I do not understand why you have not sent it for publication in a more prestigious journal. I mean, let's face it, "Energy Conversion and Management" is not exactly on par with Science, Nature, Phys. Rev. Lett., etc. As a physicist, I have never even heard of it, much less recall any significant physics papers that have come out of that. So you will understand that I find your claim to be highly dubious especially when such an important claim is made in a rather inconspicuous manner.

3. Olias did not insult you by any means, at least not from the way I have read his postings. One SHOULD NOT be naive enough to not expect to be challenged. Go to any physics conference and you will see skeptics towards a work or results, no matter how big or well-known the presenter is. This is the nature of the workings of physics. If you have such a thin skin to think what Olias has posted to be "insulting", then you're in for a very rough ride.

4. Olias cited an article that made use the same principle as the laser cooling technique. Such principles are no different than applying a B field to a bunch of electron gasses, only different level of complexities. It is of no surprise that charge particles can in fact be induced to lower their "temperatures" when put in this situation.

J. Maddox, Nature v.417, p.903 (2002)

But this is waaaaay different than a demonstration of Maxwell Demons!

Zz.
zoobyshoe
#39
Jun14-04, 01:13 PM
zoobyshoe's Avatar
P: 5,625
Quote Quote by ZapperZ
But this is waaaaay different than a demonstration of Maxwell Demons!
This can't be denied. The entity proposed by Maxwell effected a separation of high energy gas molecules from lower energy ones. The notion that you can substitute electrons for gas molecules and still be talking about the same thing is erroneous.

"...an experiment where thermoelectrons emitted from two oxide cathodes in a specially devised vaccuum tube are substituted for gas molecules in Maxwell's vessel of two portions..."

Substitute electrons for gas molecules? Any resemblence to Maxwell's entity is pretty much delusional.

The fact electrons can be deflected in a desired direction by a magnetic field is not a mystery, and not new, and does not contradict the 2nd law. It doesn't have anything to do with the 2nd law to begin with.
Olias
#40
Jun15-04, 01:16 AM
P: 258
Quote Quote by xyfu
Quote



We think these comments are terrible. Move the goalposts? Beware copies/clones? Even pirate?

We have found the real original papers listed by Mr. Olias and got their titles, authors and published dates. They are shown as follows:

1. http://www.sp.uconn.edu/~terry/images/anim/ETS.html
Animation of Electron transport in Mitochondria
copyright 1997. Thomas M. Terry, The University of Connecticut.

2. http://www.nature.com/nsu/020101/020101-1.html
New state of matter made
Physicists have created a patterned liquid.
3 January 2002
PHILIP BALL

They were published in 1997 and 2002, respectively. The former relates to bi-chemistry and latter relates to some new material. They have nothing to do with thermal electrons in a vacuum tube!

Our experiment was done during 1998 and 2001, we knew nothing about these two papers. We had got most ideas about our experiment in late 1970s, and we had a paper, which described almost all the ideas related, published in ENERGY CONVERSION AND MANAGEMENT in January 1982. The editor-in-chief of the journal, Dr. Jesse C. Denton, exchanged opinions with us many times. We also take it as one of references in the paper of Maxwell’s Demon - An Energy Conversion Experiment in Contradiction to the Second Law.

The following is the title, abstract etc of the paper published in 1982.


Energy Conversion and Management, Vol.22 pp.1 to 3 (1982)------

An Approach to Realize Maxwell’s Hypothesis
Xin Yong Fu
Department of Applied Physics, Jiao Tong University, Shanghai, China
(Received 29 January 1981)

Abstract “Maxwell’s demon”----the well known hypothesis put forward by J. C. Maxwell in 1871 has excited resonance and stormy discussion over and over among many physicists for more than a century, but never has it been realized. In this article we suggest an experiment where thermoelectrons emitted from two oxide cathodes in a specially devised vacuum tube are substituted for gas molecules in Maxwell’s vessel of two portions, while the application of a magnetic field to acting Lorentz force on the thermoelectrons offers the controlling service of the “demon”, so that electrons can only fly from one pole (A) to another (B) and a potential difference as well as an electric current can thus be gained. Through this experiment we could carry out Maxwell’s hypothesis and provide an example to break through Keivin’s formulation of the second law of thermodynamics.



Certainly, we are not so stupid to guess that Mr. Thomas M. Terry or Mr. Philip Ball has cloned our ideas.

Mr. Olias, we think you have insulted us, very impolitely.
Two things are apparent, ONE we both understand the meaning of the word 'Insulting'. TWO we both understand the word ' impolitely.

The post by me above needs some deep inquisitive exploration as to Why? and in the Relevence or Context.


This:http://www.nature.com/nsu/020101/020101-1.html

Has about as much to do with your paper as, as your paper has to do with Maxwells Demons, pretty evident I would have thought?

This:http://www.sp.uconn.edu/~terry/images/anim/ETS.html
shows the connection between isolated and connected systems, as about as experimentally viable as your system is to the surrounding 'air'.

Every Electron that hops-skips-jumps, depends on its enviroment, if it is within a connecting enviroment that is governed by the 2nd Law, then your understanding of the 2nd Law needs re-defining, not a redefinition of the Second Law?

Still, I do not take back my posting, but I will State that I have no Qualifications, so therefore you can use my lack of understanding to save face, but then again it may just be that I understand the 2nd Law just a tad more than yourself.
Olias
#41
Jun17-04, 12:19 AM
P: 258
Have you considered the implication if you could achieve this with the Crooke Radiometer !!

Interesting!

Link if you do not know what I am suggesting:http://www.sciencemuseum.org.uk/on-l...s/1920-410.asp
Olias
#42
Jun17-04, 12:23 AM
P: 258
Actually I posted the wrong link, its here:http://128.148.60.98/physics/demopag...emo/4d2010.htm

If you could achieve the experiment with a rotational axis, then you should produce motion within the vacuum tube?
Olias
#43
Jun17-04, 12:30 AM
P: 258
Easy when you know how !
xyfu
#44
Jun17-04, 06:55 AM
P: 16
Quote
Originally posted by Olias

Have you considered the implication if you could achieve this with the Crooke Radiometer !!
Interesting!



Thanks for offering the information about Crooke Radiometer. We read the introduction and catched how it works, in both the cases of high vaccum and very high vaccum.

Nevertheless, we still can not be enlightened by the Radiometer on why our experiment is not in contradiction to the second law.

Anyway, thank you for your offering.
OscarM
#45
Jun21-04, 06:15 AM
P: 11
Xinyong.

If you are correct, you will win the Nobel ;-)

I think that if you make the magnetic field bigger the orbit of electrons were closer and you could miniaturize the ZX1

It will be necessary to put a lot of plates in parallel for make an interesant current.
żAre you trying to make this?
OscarM
#46
Jun22-04, 02:21 AM
P: 11
XYFU,

I have a doubt.

In your experiment, at the theoric, you show two plates one forward the other.

------------------- +++++++++++++++++++
         A                   B


Electrons over A, goes to B. But electrons above B goes to A.
If the down part of plates are isolated with other material, only
electrons over thee plates are projected. And goes from A to B (with the
adecuated magnetic field)

But in your ZX1, (it seems that) A and B are parallel. (??????????)

  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
  --  ++
   A   B

How is possible that it works?
xyfu
#47
Jun22-04, 05:17 AM
P: 16
Dear Mr. OscarM

Thank you for the fine discussion. As to your doubt, let me try to explain as follows.

The two Ag-O-Cs cathodes can be regarded as settled on the surface of an insulated base, shown as follows. A and B are two Ag-O-Cs electrodes, IIIIIIII is some insulation material, such as mica or quartz, and symbol × represents the magnetic field:


× × × × × ×

IIIIIIIIIIIIIIIIIIAAAAAAAAIIBBBBBBBBIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

× × × × × ×


So, both the two electrodes can only eject electrons upwards. Then, due to the action of the magnetic field, every electrons, once leaves the electrodes and enters into the vacuum, turns to the right continuously and moves along a circle path, and very quickly, it returns back to the electrodes in less a circle. Its falling point is always a little drifted to the right. So, a part of electrons ejected by A near the interval between A and B, may fly overpass the interval and fall into B, but no electrons ejected by B can fly overpass the interval and fall into A.

Much clear figures of the paths of the electrons are shown in our arxiv paper, Fig.3 and Fig. 4. Please click http://www.arxiv.org/pdf/physics/0311104.

X Y Fu
xyfu
#48
Jun25-04, 12:10 PM
P: 16
The discussion about Maxwell’s demon and the related test has already lasted for about twenty-five days. Many people contributed their interesting opinions, most of which are valuable or helpful. We thank Physics Forum and all the participants very much. Nevertheless, it looks as if the discussion is a little divergent. In order to focus the attention in a better way on the most important problems, we list here again some main points of Maxwell’s demon and our experiment as follows, including some important quotations as reference. It amounts total five points.

1. The second law of thermodynamics.
2. Maxwell’s original idea, the first model.
3. Ehrenburg et al, the second model.
4. Replace electrons to molecules.
5. The problem of energy.

1. The second law of thermodynamics

In 1850 and 1851, Clausius and Kelvin established the second law of thermodynamics. They presented two famous equivalent statements of this law.

Clausius: It is impossible to device a process whose only result is to extract heat from a reservoir and to eject it to a reservoir at a higher temperature.

Kelvin: It is impossible to device a process whose only result is to convert heat , extracted from a single reservoir, entirely into work.
According to this law, all practical processes in nature are irreversible, proceeding from useful energy to waste one, like a one-way traffic. And the universe is thus destined to go forward to its eventual state, the “heat death.”

Such a law sounds strange. Nevertheless, numerous of observations and experiments confirm its validity. Few people dare to think that the “universe traffic” should be a round way one.

2. Maxwell’s original idea, the first model of demon

In 1871, the prominent British physicist James Clerk Maxwell firstly challenged this law. The following is his original words.


One of the best established facts in thermodynamics is that it is impossible in a system enclosed in an envelope which permits neither change of volume nor passage of heat, and in which both the temperature and the pressure are everywhere the same, to produce any inequality of temperature or of pressure without the expenditure of work. This is the second law of thermodynamics, and it is undoubtedly true as long as we can deal with bodies only in mass, and have no power of perceiving or handling the separate molecules of which they are made up. But if we conceive a being whose faculties are so sharpened that he can follow every molecule in its course, such a being, whose attributes are still as essentially finite as our own, would be able to do what is at present impossible to us. For we have seen that the molecules in a vessel full of air at uniform temperature are moving with velocities by no means uniform, though the mean velocity of any great number of them, arbitrarily selected, is almost exactly uniform. Now let us suppose that such a vessel is divided into two portions, A and B, by a division in which there is a small hole, and that a being, who can see the individual molecules, opens and closes this hole, so as to allow only the swifter molecules to pass from A to B, and only the slower ones to pass from B to A. He will thus, without expenditure of work, raise the temperature of B and lower that of A, in contradiction to the second law of thermodynamics.
Maxwell is a great prophet in the history of physics. He had predicted displacement current, electromagnetic waves, distribution law of the speed of molecules in a gas, the crisis of the classical physics (hydrogen heat capacities at different temperatures), and so on, and all these predictions were verified one by one, ten years, thirty years, and even fifty years after his death. We think that there is still an important prophecy of his not yet verified so far, the prophecy about the demon. It is very likely that this one is his greatest prophecy.

In Maxwell’s conceiving, the demon allows only the swifter molecules to pass from A to B, and only the slower ones to pass from B to A, and the system will change from a state in which both the temperature and the pressure are everywhere the same, to a new state in which the temperature of B is higher than that of A.

This may be referred to as the first model of the demon, (see Fig.1. *)

3. The second model of the demon

The following words are quoted from W Ehrenburg’s general review about the history of Maxwell’s demon, showing a second model.

As it happens, there is an easier way to design a perpetual motion machine that employs the services of such a sorting demon. Beginning with equal pressure and temperature on each side of the division, the demon could, by opening and closing the shutter at the right times, allow molecules to pass only from portion A to portion B. This would eventually result in a difference in pressure between the two sides, a situation even more adaptable than a difference in temperature.

W. Ehrenberg, Maxwell’s Demon,
Scientific American, pp 103-110 (1967)
By the first model, a difference in temperature is finally obtained. This is a process opposite to heat transfer.

By the second model, a difference in pressure is finally obtained. This is a process opposite to gas free expansion.

In traditional thermodynamic, both heat transfer and gas free expansion are very typical and essential irreversible processes.

We approve of Ehrenberg’s opinion that the second model is much easier to realize than the first model, (see Fig.2 *).

4. Replace electrons to molecules, a version of Ehrenberg’s model

Very similar to the gas molecules, thermal electrons ejected by a cathode in a vacuum tube obey Maxwell’s speed distribution law, too. Nevertheless, electrons are much easier to harness than neutral molecules. In our design and experiment, we replace electrons to neutral molecules.

In a vacuum tube, two Ag-O-Cs cathodes A and B are settled on an insulated base, as shown in the following diagram:

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIAAAAAAAAIIBBBBBBBBIIIIIIIIIIIIIIIIIIIIIII IIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII

where IIII is some insulation material, such as mica or quartz.

According to A H Simmer et al, Ag-O-Cs cathodes, due to their lowest work function, eject thermal electrons considerably at room temperature.

Common experience of using Ag-O-Cs cathodes shows that their thermal electron emission overpasses all other materials. The emission density of different samples may differ from each other for several grades, the typical value ranges from 10-11 to 10-14 A/cm2.

--Photo-emissive Materials, Chap.10, Sec.7.1, A. H. Sommer, 1968
The technique of photoelectric tubes and photoelectric multipliers demands an Ag-O-Cs cathode a lower thermal electron emission. If the thermal electron emission is high, the tube or the multiplier is of bad quality. In our experiment, quite contrary, higher thermal electron emission is expected.

When a stable uniform magnetic field is applied to the tube in the direction parallel to the interval between cathodes A and B (perpendicular to this paper and entering it), part of the electrons ejected by A can fly overpass the interval and fall into B, and no any electron ejected by B can fly overpass the interval and fall into A.

Such a working method coincides with Ehrenberg’s second model, (see Fig.3 and Fig.4 *).

The one-way transfer of electrons results in immediately a charge aggregation, with B positively charged and A negatively charged, and a corresponding electric potential difference is established between B and A. The device can thus supply electric power to an exterior load.

5. The problem of energy

One may ask, where comes from this electric power?

It comes from the heat extracted from the surrounding air.

As soon as A is positively charged and B negatively charged, a static electric field appears

above the interval between A and B. The direction of the electric field is such that it impedes the succeeding electrons to fly from A to B. Nevertheless, the electrons have thermal energy, or speed. The electrons overcome the impediment and fly from A to B. In so doing, they slow down, and their “temperature” falls down (slightly), resulting in a drop down (very slight) of the temperature of the whole tube. The tube then extracts heat from the surrounding air to compensate its temperature drop. The whole process converts heat extracted from the air to electric power to supply an exterior load, without producing any other effects.

It is clear and simple that the energy here is conserved. What’s new and important in this experiment is Maxwell’s idea of converting waste energy into useful energy. We think we have realized his dream.



* Note: Fig.1 through Fig.4 are in our arxiv paper Realization of Maxwell’s Hypothesis,

http://www.arxiv.org/physics/0311104
OscarM
#49
Jun27-04, 12:26 PM
P: 11
have Someone could replicate your experiment?
xyfu
#50
Jun29-04, 07:51 PM
P: 16
Nobody replicated the experiment so far.

There were two people, one in Arizona and the other in Los Angeles, asked us whether they could get a duplicate of our test tube FX1. We are managing to make some duplicates now.

Anyone who is familiar with vacuum techniques, espeicially those who is familia with the technique of Ag-O-Cs production, can make similar tubes to FX1 easily. We think that they can even make better tubes than ours, and do the experiment with better instruments.
xyfu
#51
Jun29-04, 08:17 PM
P: 16
The Problem of Magnetic Field (1)




Originally posted by Ivan Seekings
If it (the magnetic field) does work, it loses energy. Knocking electrons around is doing work.
We think that the above argument is false.

In whatever cases, a magnetic field exerts on a moving electron only a Lawrence force , which is always perpendicular to the velocity of the electron. So it is impossible for the force to do any work on the electron.

The work of the output current in our experiment is converted from the heat extracted from the surrounding air.
Dburghoff
#52
Jun29-04, 09:38 PM
P: 16
You know, I'm not a thermodynamics expert or anything, but I've got an idea. What if we're looking at this in the wrong way? Suppose that these people have created a "Maxwell demon" which creates electrical energy from heat energy. When they measured the current, that energy was most likely being converted back into heat as it passed through the ammeter. However, the heat was actually being dispersed along the entire surface of the wire and the ammeter.

Let me expand this thought. Suppose that this does work well in series, and that a power supply can be made from it. Let us suppose that an entire city is made to run on this kind of power. The electrical energy is being used in all types of appliances: blenders, TV, ham radios, etc. In the blender, the mechanical energy, lost to friction, becomes heat once again. With the TV, the light and sound is absorbed by the room that it's in, becoming heat. With the ham radio, EM waves are being scattered throughout the entire universe. A certain amount of energy which was once localized to the gas molecules in the air around the power plant is now being spread throughout the city, and some of it is actually going into space as radio waves. It seems to me that the entropy would be increasing.

Basically, what I'm saying is that this would kind of be like life. The response to the question, "Doesn't life violate entropy?" is often something like "It seems that way at first, but if you look more closely, life increases entropy." The same thing applies here as well. Though the device may seem to intially decrease entropy, it actually increases it in the long run.
geometer
#53
Jun29-04, 10:10 PM
P: 196
I've read all the posts, downloaded and read the referenced paper, and maybe I'm being naive, but this seems pretty simple to me. For this apparatus to produce an electric current, it has to set up a charge difference between the two cathodes. To set up that charge difference, you have to change the paths of at least some of the emitted electrons. Changing an objects state of motion produces a momentum change. Producing a momentum change produces an energy change. This energy has to come from somewhere (the First Law of Thermodynamics). In this case, it comes from the magnetic field. Therefore, "the heat extracted by the electronic tube from the resovoir" is only converted into electric energy after the addition of more energy to the system from an outside source: the magnet. The Second Law remains intact as far as I can see.
xyfu
#54
Jun30-04, 01:45 AM
P: 16
The Problem of Magnetic Field (2)

Posted originally by DrChinese
My point being that you assume that the magnet is not changed as work is extracted from it. I believe that the energy output (if any) is offset by matching changes in the magnet (if any).

It takes energy to create a magnet (an ordered system). But there is no way to measure the strength of a magnet to a sufficient degree of precision to detect the
subtle changes in the magnet. If you could, it would show that the magnet loses strength exactly equal to the energy output. Since the net gain is zero (or less than zero), the process obeys the 2nd law.

Posted originally by Krab
I find DrChinese’s suggestion interesting. Remember that the released electrons, in looping from one place to another, create their own magnetic field, which will act back on the permanent magnet and tend to demagnetize it.
We cannot agree with the above points.

First, we think that DrChinese’s point is not true. We hold that in our experiment, nothing is extracted from the magnet. No work, no anything else.

Please let me show our reasons.

In Faraday’s electromagnetic induction, permanent magnets are often used. These magnets are not changed at all. Dear DrChinese, do you really hold that as induced current is produced in the coil, there is something extracted from the magnet? You do think that there are some apparent or subtle changes in the magnet in such processes?

Few physicists or physics teachers and students will agree with you. According to Lenz’s Law, the electric power produced in the experiment is resulted from the mechanical work the experimentalist does. It is well known that for an ideal induction process, or we say, theoretically, according to some major principles of physics, including Faraday’s induction law, Ampere’s electric force law, and the definition of the work done by a force, the work done by the external agent (the experimentalist) equals exactly the electric power produced. So the electric power is apparently not resulted from anything extracted from the magnet.

Mr. Krab said that, the hooping of electrons from one place to another will produce their own magnet field in the opposite direction, and this magnet field tends to demagnetize the original magnet.

We do believe that no demagnetization of magnet in our experiment, as well as in the Faraday’s induction experiment.

Why?

The magnet is composed of billions of magnetic domains. The reaction of the moving electrons, or of the induced current, on the magnet, is distributed among all these tiny domains. Each domain will obtain billionth of the reaction, so the effect on each domain is very weak. The alignment of the domains will not be disturbed or destroyed by such weak effects.

A circumstantial evidence: in a common galvanometer, a permanent magnet is also used. Its coil current may range from 10 to 1000μA, which is much greater than the current we obtained in our experiment. Will the magnet be demagnetized by the coil current? Never! Evidence: Any slight demagnetization of the magnet will directly spoil the precision of the galvanometer, and the drop in precision is very easy to be found. In our daily practice, the precision of a common galvanometer is stable, which can last twenty years, fifty years, and even much longer. You may use it (provided properly) every day, having no worry about the destruction of its precision due to “demagnetization”.

In some modern electric generators with a power ranges from tens of watts to thousands of watts, permanent magnets are widely used. The currents produced in these generators are much stronger. Will the currents demagnetize the magnets? Let’s see some more practical examples.

I think both DrChinese and Mr. Krab have their private cars. They can find an electric generator in each of their cars, with an output power of, say, 500 or 1000 watts. Each generator (mostly) consists of a permanent magnet. If the car is used every day, will its magnet be demagnetized in one year? Or in two years? No, a modern magnet in such a case can be used for fifty years without any problem, and even longer.

DrChinese said that even so, there are inevitably some subtle changes in the magnet, only it is very difficult to detect them. I agree there may be such subtle changes in the magnet, several years or decades after it was produced in the magnet factory. But these changes are not resulted from the process of electric generating. Even if you don’t use the magnet at all, just put it on your desk for years or decades, some subtle changes will also happen. For example, caused by air pollution, or the bombardment of the cosmic rays, etc. Nevertheless, you can protect the magnet from these harmful influences. This is possible, and not difficult, at least theoretically this is possible.

In your car generator, the electric energy produced is resulted totally from the mechanical energy supplied by the engine. The magnet used does no work. It keeps unchanged, and it is free. Such ideas have been well accepted by the community of physicists since the nineteen’s century.

Of course, in practice, just as DrChinese said, a magnet cannot really be kept unchanged for one or two million years. But this is another problem. When discussing problems relating to physical principles, we usually speak of physical models, not the practical objects on our desk. There are many such examples in physics, let me present one here.

When Sadi Carnot investigated his famous cycle, and deduced the limit of the efficiency for all heat engines, he was dealing with physical models: an ideal cylinder, an ideal piston, a perfect gas, and so on. What’s the meaning by the word “ideal” when it is describing the cylinder and the piston? No friction between them, no abrasion, and no air leakage. Everyone knows that in practice, when a cylinder and a piston are used in an engine, no friction is impossible, no abrasion is impossible, and no air leakage is also impossible. Such ideal cylinder and piston do not really exist. They also certainly cannot exist for a period of one or two million years. But no one doubts or refuses Carnot’s brilliant conclusion deduced from these ideal models.

We should not confuse physical models with practical objects.

By the way, thanks to the rapid progress of science and technology, modern permanent magnets are of excellent quality. They are extremely close to ideal magnets. The situation is much better than the closeness of the modern cylinders and pistons to their ideal models, to say nothing about the poor and old styled cylinders and pistons available in Carnot’s time.


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