Talk:Perpetual motion/Archive 5

Basic principles section
I don’t like the formulation in the Basic principles section.

Point 1 is OK.

Point 2 You always lose a little energy (second law of thermodynamics) suggests that the second law violates the first law since it allows that energy (just a little!) can get lost. This must confuse the reader.

Point 3 Therefore a machine cannot make more energy than it uses or even enough to keep itself operating suggests that the energy, leaving a machine, is smaller than the energy going in. So, also this formulation suggests that energy is not conserved.

A more precise way of formulating would be:

2. The output power of heat engines is always smaller than the input heating power. The efficiency (this is the produced power divided by the input heating power) has a maximum, given by the Carnot efficiency. It is always lower than one.

3. The efficiency of real engines is even lower than the Carnot efficiency due to irreversible processes.

Please respond.

(Adwaele (talk) 21:04, 29 April 2012 (UTC))


 * I agree that the existing wording is sloppy. Your suggestions seem reasonable.Prebys (talk) 00:33, 30 April 2012 (UTC)
 * I also like this proposal but think readers will wonder about other types of engines besides heat engines (it begs the question). Can we generalise it? Joja  lozzo


 * OK, I will adjust the text in the Article.Adwaele (talk) 08:04, 30 April 2012 (UTC)

Quantum perpetual motion machine
Did anyone see the article in Scientific American some time in the last 5 or 10 years about the quantum perpetual motion machine? Apparently the second law of thermodynamics doesn't apply at the quantum level, so this guy invented the machine just to demonstrate the principle. I forget the details, but I think he was some Chinese guy with a PhD in theoretical physics working for some big research facility like IBM or the like. The research paper was public either in Nature or Science (I forget). The SciAm article was pretty short, about 2 or 3 paragraphs. The scientist was quoted as saying that his invention has absolutely no practical applications, that it can't be scaled up, and that its importance to science is trivial, since it merely demonstrates a principle of physics that was already widely known. Zyxwv99 (talk) 14:18, 4 October 2012 (UTC)
 * You know, it's considered good manners to do your own googling, rather than rely on others to do it for you. I was able to find this, from a year or so ago about an obscure entanglement phenomenon that results in principle results in negative entropy.  I think it's a bit too technical for this article, but if you want to put in a section about the 2nd law at the quantum level, go ahead.Prebys (talk) 14:31, 4 October 2012 (UTC)


 * It's tricky...at the quantum level, the concept of temperature breaks down - it's just motion, kinetic energy. Since the second law is all about temperature transfer...it's really tough to say that it's been "broken" at the quantum level.  But quantum systems and things like super-conductors that have zero electrical resistance do challenge some of the definitions of "perpetual motion".  This one (if indeed it works) seems to be "Perpetual motion of the third kind" - which is really the least interesting.  If we're going to write about it, let's just be super-careful not to let the free energy nut-jobs get the idea that we'll soon be powering our civilization from a bunch of quantum perpetual motion machines!  SteveBaker (talk) 14:39, 4 October 2012 (UTC)


 * First of all, I didn't ask anyone to Google it for me, I asked if anyone else had already heard about it. Next, no one said anything about the second law of thermodynamics being "broken," just that it doesn't apply at the quantum level. As for what effect this would have on the yahoos, hopefully something similar to Rutherford transmuting lead into gold circa 1918. Once people understood that it could be done, and how it worked, they realized that it was impractical. Zyxwv99 (talk) 15:26, 4 October 2012 (UTC)

Edit request on 25 October 2012
The first description of a perpetual motion machine was found to be made by the Indian mathematician and astronomer Brahmagupta in 624. In his Brahmasphutasiddhanta, he describes a perpetual motion device: "Make a wheel of light timber, with uniformly hollow spokes at equal intervals. Fill each spoke up to half with mercury and seal its opening situated in the rim. Set up the wheel so that its axle rests horizontally on two [upright] supports. Then the mercury runs upwards [in some] hollow spaces and downwards [in some others, as a result of which] the wheel rotates automatically forever." (transl. S. R. Sarma)


 * Transl. S. R. Sarma, Astronomical Instruments in Brahmagupta's Brahmasphutasiddhanta, Indian Historical Review, XII 1986-87, p. 69-71) and Perpetual Motion in Machines and their Design in Ancient India, Physis - Rivista Internationale di Storia della Scienca, vol. XXIX (1992) fasc. 3 p.665-676.

Aravindsai41 (talk) 19:49, 25 October 2012 (UTC)


 * Your proposed wording is identical to the second passage of this webpage. That's not a problem (we can reword it), but if that's where you found the information we should cite that page instead. Is that website your source, or do you have access to those two journals? DoctorKubla (talk) 06:39, 26 October 2012 (UTC)
 * ❌ Copyvio. -Nathan Johnson (talk) 14:11, 28 October 2012 (UTC)

Broken Radius Concept
http://www.youtube.com/watch?v=UdZ2NJjnUEk — Preceding unsigned comment added by JacobsLadderProject (talk • contribs) 23:14, 9 December 2012 (UTC)


 * If I understood the video, this is a "mass leverage device", which tries to extract energy from gravity by a rotating belt with weights on it. Supposedly the belt is perpetually unbalanced, with more weight on one side than the other, and turns continuously.  Nothing new here, such devices have been tried (and have failed) at least since the Renaissance.  A similar device is pictured in the article.  He will find at some point in its cycle his belt is balanced and will stop moving.  I particularly like how he justifies perpetual motion with an appeal to the Bible. -- Chetvorno TALK 02:55, 10 December 2012 (UTC)

perpetual motion machines and the "scientific method"
No mention is made in any of your articles on this subject about something called "the scientific method". There is no proof of a theory unless at least one of the most basic tenents of the "scientific method" are followed when conducting an experiment to prove a theory as part and that is the fact that the test or experiment must be reproducable, particularly by a different party than the one that proposed it. Since this has never occured, one must assume that some of these perpetual motion machines, or even Lester Hendershots machine that is said to use the gravitational force of the earth to produce more energy than it uses (really not perpetual motion but just as bogus)are far out theories at best and charlatans at worse. Most people that fall into this catagory are really just making money off of publications of their work or at worst, duping investors. Stick to the "scientific method" and at least you won't be labeled a phony and at best you may have somthing that works.

(Rodcarrx (talk) 18:29, 13 March 2013 (UTC)) Rodcarrx


 * You are correct that no claimed "perpetual motion" (or "overunity", or any of the other names these people use to obfuscate what they're about) machine has ever been shown to work by independent experimenters who were qualified to detect fraud. And "experiments repeated by multiple independent observers" is indeed part of the scientific method. But you should understand that "proving that a machine works" is not really what the scientific method is about. The scientific method is a protocol for establishing the plausibility of theories for how the world works. But, strangely (to many), there is never any "proof" of the truth of a theory under the scientific method. You can challenge it (by experiment) and find that it meets the challenge (or, if it doesn't, then the theory is disproven), but that doesn't prove that it will meet every possible challenge in the future. The more challenges the theory passes, and the more times those experiments are repeated, the better... but it still isn't proof. Jeh (talk) 18:43, 13 March 2013 (UTC)


 * According to your way of thinking, there is no such thing as proof, only a closer approximation with each re-trial. I would be happy with one extra confirmation, but it never happens. The more people that can repeat it the better, but without even one, it's bogus. Rodcarrx Rodcarrx (talk) 19:18, 13 March 2013 (UTC)


 * That isn't "my way of thinking", that's how the scientific method works: there is no such thing as absolute proof of a theory, only disproof! However, the more challenges (attempts to disprove) a theory withstands, the more accepted it becomes and the more it is assumed to be true—at least under the conditions under which it has been tested so far. Jeh (talk) 19:43, 13 March 2013 (UTC)

Rodcarrx The point I am making is that I agree with you, but you cannot get to the point of many attempts without starting out getting through one additional successful attempt. There does not exist one additional reproduction to perpetual motion machines or to Lester Hendershot's machine. How many decades do you want to give it before declaring it cannot be reproduced? Rodcarrx (talk) 20:39, 13 March 2013 (UTC)


 * You are absolutely right, Rodcarrx, and that is why no reputable scientist believes perpetual motion is possible. The impossibility of perpetual motion is established theoretically by the laws of thermodynamics, and has been tested as much as any theory can be, and more than many other accepted scientific theories have been, by the many attempts at achieving it.  While technically as Jeh says no theory can be proven empirically, only disproven, the impossibility of perpetual motion is about as close as we can come to a proven theory. -- Chetvorno TALK 13:07, 11 May 2013 (UTC)


 * The problem, as always, is in the definition of "perpetual motion". The earth has been spinning on its axis for billions of years, and will seemingly continue to do so for billions more years until it gets melted by a dying sun. This is "scientifically proven fact", and umpteen billion years of motion is as close to perpetual as makes no difference. Electrons are present in every atom, and its scientifically proven that they will continue in their orbital motions for eternity. Perpetual motion therefore clearly is possible. Harnessing this motion has not yet been done (YET), but the Nile River has not run dry for 7000 years that we know of, so barring maintenance issues a water wheel dipped into the Nile should produce "perpetual" motion as well as useful energy output "in perpetuity". None of these examples fit the purist definition of perpetual motion, but they are enough to inspire people to continue to dabble with permanent magnets and gravity motors, as well as trying to tap into "the cosmos". As has been said above - just because it hasn't been done yet, doesn't mean it won't be done next week. Nobody every built a flying machine until the first guy built a flying machine. Nobody ever broke the sound barrier until the first guy did it. Nobody ever walked on the moon etc etc. Its all a matter of definition, and innovators refuse to accept "perpetual" motion is impossible for as long as the earth keeps spinning along. Wdford (talk) 10:08, 13 May 2013 (UTC)
 * This is all dealt with in the article and the discussion above on this page, which you participated in. The examples you give are not perpetual motion according to reliable sources and this article, and all obey conservation of energy - they will run out (except the motion of electrons; extracting energy from them would be perpetual motion but is impossible because of the 2nd law of thermodynamics).  We can't make up our own definitions; sustainable and renewable energy sources are not considered perpetual motion.  Tapping into the power of the Nile is not perpetual motion, it's called hydropower and has been used for 2000 years.  Exploiting the energy of the motion of celestial bodies is also not perpetual motion; one form is tidal power which has been used since the 1940s and is being actively developed now, by the conventional engineering community.    Flying machines, faster than sound travel, and walking on the moon don't violate conservation of energy or the 2nd law of thermodynamics.  They were not accomplished by ignorant people, ignoring physical laws, dabbling with magnets and crystals in their garage.  They were accomplished by scientists, engineers and even self-educated people (the Wright brothers), whose common characteristic was that they didn't reject the body of scientific knowledge that man has built up over the last two thousand years.  They did the hard, boring work of studying the techniques that are used in their field, the "prior art", the "tools of the trade", mathematics, physics, chemistry, so they could add to the sum of human knowledge, and achieve things that have never been done before.


 * But the people in the "overunity" community don't want to do this. Ostensibly it is because this doesn't fit their romantic but unrealistic vision of the inventor as everyman-rebel, the ordinary uneducated man who by his common sense, persistence, and independent refusal to except "conventional wisdom" discovers the principle that the stuffy scientific establishment overlooked.  But actually it is because they are lazy.  As SteveBaker said, the vast majority tinker with well-understood technology, repeating, in their ignorance, ideas that have been tried hundreds of times before, or that an engineer could tell at a glance would not work.  This is why most scientists can't work up much interest in perpetual motion machines: not only because they transparently don't work, but because they are unoriginal.  The same boring designs, the same mistakes are made, over and over again. -- Chetvorno TALK 16:13, 13 May 2013 (UTC)


 * I agree with your summary re the definitions, I merely add - yet again - that the reason why thousands of competent people continue to tinker away is because not all of them use the same definitions as you. I can't comment on the psychology of every innovator. Some are presumably fraudsters, and some are quite possibly nuts, while others are merely ignorant or untrained. However many of these people are well-qualified and hard-working scientists, engineers and artisans, who are plodding along down that road because their training and experience tell them that there are indeed loopholes that might one day yield the solution. Undoubtedly any future successful device will prove to be tapping some energy source or other, as solar panels do, but these people don't care where the energy comes from as long as its free and can make the world a safer happier place. They are not trying to "prove science is wrong", or to "prove science is stuffy", they are in search of a solution and they are not constrained by a pedantic interpretation of scientific jargon. To label them all as phonies and fraudsters is highly inappropriate - many of them put all their time and all their personal wealth into this pursuit. Wdford (talk) 08:03, 14 May 2013 (UTC)


 * That was the whole point of this thread; that the definition of perpetual motion is not arbitrary, based on a "pedantic interpretation of scientific jargon", it is based on the most firmly established physical laws we know,  with 200 years of theoretical proof and 500 years of empirical testing behind them, the closest science can come to certainty.   People who are pursuing perpetual motion, whether they know it or not, are trying to violate conservation of energy or the 2nd Law.  People whose devices are not attempting to violate these laws are not doing perpetual motion; that's the definition.   All thermodynamics is saying is that virtually everyone who has produced new sources of energy has found these laws useful, while in 500 years of continuous trying, as far as we know, not a single milliwatt of energy has ever been produced in violation of these laws.  Whether the people who are trying to discover new sources of energy find this useful is up to them. -- Chetvorno TALK 05:56, 19 May 2013 (UTC)

Pendulum question
Is a pendulum a perpetual motion machine? - Sidelight 12 Talk 07:05, 20 May 2013 (UTC)
 * Only if it never stops moving. In other words, no. 152.119.45.23 (talk) 17:12, 22 May 2013 (UTC)
 * Thank you for your answer. - Sidelight 12 Talk 20:58, 22 May 2013 (UTC)

?
"While perpetual motion is a physical law derived from logic, whereby it's constrain on technical designs is absolute." - what does this mean? Volunteer Marek 07:17, 2 June 2013 (UTC)
 * Assessment of technical designs of perpetual motion machines, in which the complete set of function of state transitions and their constrains by equivalence relation are examined, can lead to definite conclusions about its functionality without the need for additional physical examinations or test runs of actually build devices. The laws of thermodynamics are primarily based on conceptual frameworks, whereby their application is first and foremost to technical drafts instead of actual constructed/assembled devices.FrankRadioSpecial (talk) 09:41, 2 June 2013 (UTC)

Should article be renamed to include the word "concept"
Should this article be renamed to "Concept of perpetual motion" or "Perpetual motion concept"? - Sidelight 12 Talk 20:58, 22 May 2013 (UTC)
 * Since the word "perpetual motion" is the most common way to refer to the concept perpetual motion, I think the present name is just fine. -- Chetvorno TALK 22:01, 22 May 2013 (UTC)
 * An alternative might be to edit the introduction, so that it includes the word "concept".FrankRadioSpecial (talk) 09:49, 2 June 2013 (UTC)


 * People know fairies don't exist, it doesn't need pointing out in "Fairies (imaginary)". Same for this. The article itself is almost completely an explantion of why the concept is wrong. The article doesn't need renaming "concept", as if to distinguish it from actual perpetual motion machines. It only ever is a concept. 92.40.253.143 (talk) 04:04, 27 June 2013 (UTC)

Friction
As the link on this article's page to "The Museum Of Unworkable Devices" points out, it is not friction that defeats perpetual motion machines. Such machines fail to work because the inventor misunderstands the forces involved, so the machine soon achieves a state of equilibrium, rather than the state of constant unbalance needed.

To sum up, friction isn't the problem. It's the designs of the machines that are flawed.

So the links to the dictionary definition at the top need removing. Dictionary writers aren't scientists, and as the continuing persistence of this nonsense through the centuries shows, most people don't understand the physics of this properly.

The "Museum" itself does a good job of trying to pin down this fairly elusive concept, again, it's the elusiveness and subtlety that's kept fooling people over the years. The article needs a combing-through, and I'd use the Museum itself as the source for most of the principles of scientific stuff. Dictionaries are pretty terrible sources of science, especially on misunderstood subjects like this.

It's a hard subject to understand, it really needs writing by someone who understands it well. Any talented physics teachers, or bored LHC researchers want to take up the challenge?

92.40.253.143 (talk) 03:59, 27 June 2013 (UTC)


 * That's not really what the article says. It says that friction isn't the ONLY thing that prevents perpetual motion machines from working. Other real-world mechanical actions, such as the deformation of elastic bodies, also prevent perpetual motion. Sterling.M.Archer (talk) 22:22, 23 September 2013 (UTC)
 * Deformation of a perfectly elastic body would only store energy, not dissipate it, so it could presumably be retrieved later. Did you mean "inelastic bodies"?  Regardless, I agree with you that 92.40.253.143 doesn't have it right.  -- Chetvorno TALK 23:37, 23 September 2013 (UTC)
 * Yes, my mistake. Sterling.M.Archer (talk) 17:08, 27 September 2013 (UTC)

Rail gun
Well, this one will keep the scientist busy for a while... http://www.youtube.com/watch?v=Vo2-Qb3fUYs Perpetual motion impossible? A couple of teenagers just dogged that theory. — Preceding unsigned comment added by 24.184.110.39 (talk) 05:15, 21 September 2013 (UTC)
 * That's a rail gun. It doesn't have anything to do with perpetual motion.  -- Chetvorno TALK 05:20, 21 September 2013 (UTC)
 * The idea is to connect it in a circle. http://www.youtube.com/watch?v=HOVcinQ-7TQ DarkLightA (talk) 18:41, 2 October 2013 (UTC)
 * Then the slider will soon reach an equilibrium point where the forces pulling it back equal the forces pulling forward, and will stop moving. n.b.: Angling the magnets does nothing. Jeh (talk) 19:23, 2 October 2013 (UTC)

"Free Energy"
The disambiguation page for Free Energy points here as the only source of information for devices based on "alternative" physics - and as such the description "Perpetual Motion" is incomplete.

At the heart of quantum theory is the concept that energy/matter is constantly being created and destroyed. Researchers have therefore considered "energy from the vacuum" devices. In the realm of electricity, researchers have found ways of setting up asymmetry so that for instance back EMF in a transformer secondary or motor is cancelled out. Whilst references to this field should be guarded, arguably they should not be dismissed. Dollist (talk) 19:46, 7 July 2014 (UTC)


 * I'm afraid you've been taken in by pseudoscience. The source you gave is quite wrong.  Quantum theory is based on conservation of energy, and does not allow energy/matter to be created or destroyed, only changed in form. The motion of electrons and zero-point energy cannot be tapped due to the second law of thermodynamics.  "Alternative" physics is bogus physics.  The "energy from the vacuum" theories of John Bedini, Tom Bearden, Gabriel Kron, etc. are horse manure.  Not a single paper by any of them has been accepted by any reputable scientific journal.  Their claim that the reformulation of Maxwell's equations by Oliver Heaviside around 1900 ignored asymmetric solutions that allow back EMF in a motor to be cancelled is laughable to any real physicist.  None of the devices on that page work.  They sound convincing though, don't they?


 * These people have learned to dress up their fantasies by mixing them with real physics so they sound like real physics papers, so they deceive a lot of uneducated readers. -- Chetvorno TALK 22:05, 7 July 2014 (UTC)
 * Tom Bearden is the absolute master of technical-sounding gobbledegook. In addition to all the stuff he's written, he loves the sound of his own voice, and you can find hours of him talking on YouTube. If anything uses him as a reference, it's safe to stop reading.  The fact that people keep falling for his nonsense is why I argued strongly NOT to delete the Wikipedia article about him, but I was outvoted, because the fact is, he really isn't "notable".  KaturianKaturian 19:03, 8 July 2014 (UTC)
 * ...but back on topic: Your reference (Patrick Kelly's "Guide to Free Energy Devices") is nowhere near a WP:RS; however, it is extremely useful as a comprehensive list of fallacious claims.KaturianKaturian 19:11, 8 July 2014 (UTC)

More clarification of terms needed?
There are a few things that could potentially be in perpetual motion based on some of the definitions on the page:

1 Any object in space - An object moving through space will continue to move (perpetually) unless something gets in the way. As far as I know two objects that orbit each other could orbit perpetually if they are in a stable configuration (but I don't know if tidal effects would always end up destroying the stable state?

2 When you create a superfluid you can, as far as I understand it, create a perpetual fountain - the fluid will keep moving so long as the temperature remains low enough. — Preceding unsigned comment added by 86.140.242.235 (talk) 12:43, 24 January 2014 (UTC)


 * The motion of celestial bodies has been discussed repeatedly on this page - see "Definition" above. There are various sources of drag, such as interstellar gas, tidal deformation, and gravitational waves, which dissipate the energy as heat, so orbiting bodies will eventually "spiral in"; it just takes a long time.  Superfluidity might be an example; the similar example of perpetual superconductive electric currents is already mentioned in the introduction.  However I have read that in practice superconductive currents don't actually flow forever, but dissipate energy by several small mechanisms which cause the currents in devices like superconductive magnets to decay to zero on a time scale of months, so perhaps superfluid motion also decays. It would have to be sourced. Just observing a superfluid's motion requires light to reflect off of it, and the light photons will carry off momentum from the fluid in the form of a tiny Doppler shift - in the real world there are all kinds of tiny dissipative effects that prevent a motion from being truly "perpetual".  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 18:24, 24 January 2014 (UTC)


 * It's true to say that in theory an object could continue to spin or move in a straight line at constant velocity perpetually - but in practice, you can't ever quite manage it. With relativity, it's arguable that an object doesn't move at all when it's going at constant velocity because it is an equivalent statement to say that the entire universe is simply moving the other way.  An object that appears to be "stationary" is moving...so it all gets very tangled when you try to argue purely theoretically. SteveBaker (talk) 19:49, 8 July 2014 (UTC)

Definition

 * Perpetual motion describes "motion that continues indefinitely without any external source of energy; impossible in practice because of friction." ... There is a scientific consensus that perpetual motion is impossible, as it would violate the first or second law of thermodynamics.

I don't think that this wording is adequate. It's easy to read it as saying that motion continuing indefinitely is theoretically impossible according to the laws of thermodynamics, which is not true at all. 86.167.124.147 (talk) 17:23, 22 June 2013 (UTC)
 * Can you give an example of macroscopic motion that will actually continue indefinitely without any external source of energy? -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 17:51, 22 June 2013 (UTC)
 * Firstly, there is no mention in the definition of "macroscopic". If you want a macroscopic example, though, an orbiting body will, ignoring exotic effects, continue orbiting forever in a vacuum. The laws of thermodynamics do not preclude this, and, in fact, one could argue that the laws of thermodynamics say the exact opposite: that motion always will continue forever. 86.167.124.147 (talk) 18:01, 22 June 2013 (UTC)
 * It would have to be a perfect vacuum without a single subatomic particle, which doesn't exist in the universe. The rest of the universe would have to be empty of other objects, because if there are any other objects in the universe at a temperature above absolute zero, the momentum carried by their black body radiation will slow the orbiting object.   Even then a body orbiting another one will radiate energy in the form of gravitational waves and will slowly spiral in.  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 18:12, 22 June 2013 (UTC)


 * Actually, I have a problem with the above definition, too. That definition, from the word perpetuum mobile, comes from a time before the concept of energy was understood.  In modern physics, the idea of perpetual motion has expanded to include devices that produce electrical, chemical or other forms of energy besides mechanical energy.  The modern definition is: a device that produces energy without any energy input, or (in the limiting case) a device that runs without input of energy.   The definition of "motion that continues indefinitely"  has to remain the primary definition in the article because it is in most WP:RSs, but I'd like to add an explanation of the modern energy definition, if I can find a source. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 01:51, 24 June 2013 (UTC)


 * I would support that. The current definition actually isn't bad, but the more precise the definition, the easier it will be for readers to understand that over-unity is actually possible if you are drawing energy from another source, but that the "rules of physics" forbid an over-unity device if it tries to create energy out of nothing. The sooner we update this definition the better. Wdford (talk) 07:53, 24 June 2013 (UTC)

The current 'scientific' definition is a bit of a fudge, as it assumes that the definition of energy is 'energy know to science' to the exclusion of any unknown-undiscovered energy source.(See cold fusion) This further assumes that no new energy source is possible because science knows all possible energy sources. This is surely not in the spirit of science as it assumes that science knows everything about energy. Therefore: it is impossible for a machine to run on an energy source unknown to science, now or at any future date? What became of logic? — Preceding unsigned comment added by 86.163.72.245 (talk) 22:40, 13 October 2013 (UTC)


 * As the article says, new physics may be discovered tomorrow.  All it is saying is that the impossibility of perpetual motion (based on conservation of energy and the 2nd law) is the closest thing to a universal law we know.  It is one of the oldest (dating back to the Renaissance) and has been the most challenged.   In its 400 year history it has been continually attacked and has not only stood up, but has been found to lie at the foundation of all modern physics.


 * All the physical laws we know about, back to the Big Bang, are based on conservation of energy and therefore do not permit perpetual motion. Any "undiscovered sources of energy" that can be explained by known physical laws must be "limited" sources and not "unlimited, perpetual" sources. This would have included cold fusion, if it had panned out, which was not "perpetual motion" but merely a new way of burning the limited fusion fuel available on Earth.  Of course new physical laws may be discovered.  But Noether's theorem makes it pretty difficult even for any new physics to permit perpetual motion.  It says any law of physics, known or future unknown ones, which obeys time symmetry, meaning it is unchanging in time (which is what makes it a "law"!!) must conserve energy and therefore prohibit perpetual motion.  This is all explained in the article; did you read it? -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 08:47, 14 October 2013 (UTC)


 * Surely at atomic level, the motion of matter cannot actually stop. I think the problem is with the term 'perpetual motion', when what is actually meant is that a machine carrying out 'work' indefinitely is impossible.  I think the movement of stars etc is perpetual motion, if not, then when and how are they going to stop?  Theories about the ultimate fate/future of the universe vary, with talk of heat death on one hand, and accelerating expansion due to dark energy on the other. Gomez2002 (talk) 11:45, 28 July 2014 (UTC)


 * You're right about the motion at the atomic level; any matter at a temperature above absolute zero has thermal energy. If we could tap that, it would be a truly "perpetual" source of energy, because all energy ultimately degrades into thermal energy, so it would be a closed cycle; a self-renewing source.  That is what a "perpetual motion machine of the 2nd kind" claims to do.  The 2nd law of thermodynamics forbids this; in order to extract useful energy from thermal motion you need a reservoir at a lower temperature, and any process that extracts work from the higher temperature reservoir exhausts heat into the lower temperature reservoir.  So even though there is atomic motion, useful energy cannot be extracted from a system at a constant temperature.


 * In addition to any extraction of useful work by us, due to "entropy" spontaneous processes slowly degrade and dissipate any "nonequilibrium" reservoirs of energy, for example temperature differences, or moving objects like planets, until eventually the universe will reach "equilibrium"; there will be motion on the atomic scale, but no usable energy; the heat death you mentioned.   The motion of celestial bodies has been discussed on this page repeatedly; processes like drag due to interstellar gas, tidal distortion, and gravity waves will dissipate the kinetic energy of orbiting stars and galaxies, so they will eventually "spiral in"; it just takes a long time (a LOONG time).  Dark energy MIGHT be an exception, but it is only active on a very large scale; anything the size of a galaxy or smaller is going to suffer heat death; I would assume it would slowly collapse and end up as a black hole.


 * I absolutely agree that the problem is the term "perpetual motion"; as you say, what most people mean by the term is a machine that will produce work with no energy input. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:21, 28 July 2014 (UTC)

jul 29, 2014, Almost Perpetual Machines,
jul 29, 2014, How is this working then? https://www.youtube.com/watch?v=HWa21NSQsJw, https://www.youtube.com/watch?v=7KqOwJKWIAw , — Preceding unsigned comment added by Nayanmipun (talk • contribs) 07:32, 29 July 2014 (UTC)
 * They are (as their titles and comments tell you) examples of overbalanced wheels. This is one of the older (and now less-novel) well-known failures to be actually perpetual motion. It's easily debunked by basic physics, as already discussed in our article. DMacks (talk) 08:04, 29 July 2014 (UTC)
 * The overbalanced wheel seems to be the only example which isn't explicitly debunked, in the article - until I copyedited it, it just said "the result is (or would be, if such a device worked) that the wheel rotates". Is there a snappy explanation of why the expectation of perpetual rotation is incorrect? --McGeddon (talk) 08:31, 29 July 2014 (UTC)
 * The caption in the gallery section seems like a good sound-bite: "The "Overbalanced Wheel". It was thought that the metal balls on the right side would turn the wheel because of the longer lever arm, but since the left side had more balls than the right side, the torque was balanced and the perpetual movement could not be achieved. That's in keeping with the explanation in footnote #22 (10.1016/j.physrep.2012.10.007) cited in the main article where you were editing. DMacks (talk) 09:06, 29 July 2014 (UTC)
 * Oh, I missed the gallery. Seems unhelpful to be splitting such text between a section and the gallery, I'll try cleaning it up. --McGeddon (talk) 09:16, 29 July 2014 (UTC)
 * I agree. Thanks for your work on it! DMacks (talk) 09:21, 29 July 2014 (UTC)

Given that two of the gallery images could usefully illustrate two paragraphs, I've moved them. This just leaves File:Perpetuum1.png in the gallery, which seems a bit lost by itself. Should this replace the other image of the overbalanced wheel, File:Perpetuum mobile villard de honnecourt.jpg? The newer image is clearer, but the older one may be of historic significance, and at least conveys the age of the idea. --McGeddon (talk) 09:30, 29 July 2014 (UTC)

Another problematic statement
As an outcome of the above discussion (I believe), the opening definition now reads much better. However, there is a similar problem at the start of the next section:


 * "There is a scientific consensus that perpetual motion in an isolated system violates either the first law of thermodynamics, the second law of thermodynamics, or both."

This is simply not true. Perpetual motion (as it is defined in the opening sentence) does not violate any physical laws. 81.157.14.203 (talk) 20:49, 24 September 2014 (UTC)

... though I said that the opening definition read much better, now I am wondering. Is this distinction between "perpetual motion" and a "perpetual motion machine" actually real, or just someone's invention to fudge the wording? (No offence.) Does a "perpetual motion machine" not do "perpetual motion"? 81.157.14.203 (talk) 20:58, 24 September 2014 (UTC)


 * The issue is really a historical and linguistic one. The term "perpetual motion"  from the Latin perpetuum mobile originated in the Middle Ages, before the concept of energy was understood.  People tried to build a machine that would turn "by itself", indefinately. The repeated failure of these efforts led to the concept of energy and conservation of energy, which explained why they were unsuccessful.  The modern meaning of perpetual motion in physics has expanded beyond a machine that will turn forever.  It means a machine that produces more energy than it consumes, in other words a machine that produces energy from nothing (or in the case of a perpetual motion machine of the 2nd kind, one that produces energy from thermal motion at equilibrium).  The term is extended to other types of energy than motion; an electrical generator that produces electric energy with no input fuel would also be called a perpetual motion machine.-- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 00:25, 25 September 2014 (UTC)


 * The anachronistic term "perpetual motion" has led to an enormous amount of confusion on this page; people bring up examples like the motion of the Moon or planets, and ask "is this not perpetual motion?" The answer is no it's not, because it doesn't produce energy from nothing.  These are just examples of motion with very little friction.  A moving object only has a certain amount of energy.  Every form of motion is subject to some form of friction, which dissipates its energy, so unless it can produce energy from nothing, it will eventually stop moving.  For example, the Moon circling the Earth is subject to drag from the thin interplanetary gas as well as tidal deformation, so it will eventually "spiral in" and collide with the Earth.  If you want to show that perpetual motion is possible, you have to show that energy can be produced from nothing. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 00:25, 25 September 2014 (UTC)
 * Thanks, but I stand by my original comments. Firstly, I do not believe that the distinction between "perpetual motion" and "perpetual motion machine" as made in the opening sentence is valid (or widely recognised), and secondly I do not believe that the statement at the beginning of the "Basic principles" section is true, given the definition at the start of the article. Probably we should focus specifically on what should be done to fix these two issues, if it is agreed that they need fixing. 81.157.14.203 (talk) 02:40, 25 September 2014 (UTC)


 * What exactly is your objection? I don't see that there is much of a distinction being made between the terms.  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 03:04, 25 September 2014 (UTC)

Fix, don't delete
After spending considerable time attempting to clean up the mess that the LEDE had become, I found all my hard work RVed with a nice note about how it was wrong and unsourced. Neither statement was true, but I guess that's why I'm now here, having to ask what precisely was wrong with it so that I can fix those statements and re-implement. Maury Markowitz (talk) 20:01, 18 October 2014 (UTC)
 * "Perpetual motion, in the strict sense of the term, is both theoretically possible and seen in practice. The galaxies in the universe will move forever, by any practical definition," is something that caught my eye as being incorrect, unless you have a specific definition of "practical definition" in mind. "Runs a long time" is definitely not "perpetual", especially if there are multiple possible end-states, such as heat death of the universe--essentially, their motion was initiated by energy input (Big Bang or something) and will eventually wind up being converted to other forms rather than motion. It's only perpetual in a sense similar to the next discussed ideas, such as hydroelectric power or other beyond-Earth sources. DMacks (talk) 20:42, 18 October 2014 (UTC)


 * I agree with DMacks. Point taken, Markowitz; I probably should have discussed before reverting.   Here are my issues with the rewrite:
 * "Perpetual motion, in the strict sense of the term, is both theoretically possible and seen in practice."
 * The biggie. Wrong and misleading. Many, many sources state that perpetual motion is impossible.  Perpetual motion of the third kind, frictionless motion, which is what is being referred to in the "galaxies" example, is almost possible, but as has been discussed many times on the Talk page, is not actually possible because it is not possible to have motion without some friction or energy loss.


 * "The exact nature of the failure of these devices was different in every case - the endless waterwheel fails for different reasons than the overbalanced wheel"
 * This is misleading for nontechnical readers. The most important fact in this article is that all perpetual motion machines fail for one or the other of the same two reasons: They either violate conservation of energy (the first law of thermodynamics) or the second law of thermodynamics.  These points should be up near the top.    The quote above encourages the common view that all it takes for perpetual motion is for someone to find a better linkage or a different method.  Maybe instead make the point that the fact that so many different designs failed led Enlightenment scientists to the idea that a general principle was involved - conservation of energy.  Plus the readers haven't been told what a "endless waterwheel" or "overbalanced wheel" is.


 * "...a device that continues to operate with no external inputs while producing useful work"
 * What kind of "inputs"?


 * "Designs for such devices were popular for centuries..."
 * I feel this wording may be misinterpreted to mean the ancients had the "secret".


 * "Many perpetual motion machines fail because the design inherently requires more energy to run than the system contains..."
 * This should be reworded; a perpetual motion machine of the first kind requires an "infinite" amount of energy.


 * "More modern designs, especially those that do not provide physical motion directly, tend to be based on the conversion of energy from one form to another."
 * Something should be said here about heat or thermal energy; the defining characteristic of perpetual motion machines of the 2nd kind is that they convert thermal energy to work. Also I wouldn't say they were "more modern designs" but that they are a different class or type  because they fail for a different reason.
 * -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 23:00, 18 October 2014 (UTC)


 * Many, many sources state that perpetual motion is impossible Sources talking about perpetual motion ''machines'. If you do not believe the galaxies are in perpetual motion, you might want to read up a bit more on dark energy. As to "practical definition", anyone can state that anything is not "perpetual" because it had a beginning in time, yet such a definition is not practical. A practical definition would have to include provisions for the time that the device starts and may be deliberately stopped. But adding such distinctions is precisely the sort of overcomplicating that confuses more than
 * This is misleading for nontechnical readers. I say the exact opposite. The Browning Ratchet doesn't work because of the 2nd law, that simply tells you that you're probably not looking hard enough. The actual reason that it doesn't work is described in the article. And that reason is different than the reason the overbalanced wheel doesn't work, or the waterwheel example. All of these fail for different reasons, and simply saying "2nd law" is far, far more confusing than pointing out the actual reasons.
 * If you think the wording is unclear, or too wordy (guilty!) then by all means fix it. But the current lede is a shitstorm of far more confusing terminology. One issue pointed out above is introducing things the reader hasn't seen before, but the current version has a whole section about superconductivity that adds nothing but confusion and apparently is an attempt to demonstrate a counterexample and then explain it away. Come on.
 * Chetvorno has some excellent suggestions at the end there. So here goes...

Perpetual motion is motion that continues indefinitely without any external source of energy. The term is most commonly used to refer to a perpetual motion machine, a device that continues to operate with no external inputs while producing useful work.

Proposals for perpetual motion machines have been made for centuries, although they all failed in practice. Early examples generally used basic mechanical systems to produce closed loop motion, using falling water to power a water pump for instance. Later examples tended to be based on any new scientific discovery; magnets, electrical systems and various materials effects have all been proposed. Before the mathematical understanding of the concepts of work and energy had been developed, there was no obvious reason why these devices would not work, and the failure of one design was not taken as an indication that another would not work. The development of modern physics, especially the concept of energy and the science of thermodynamics, has demonstrated that any such device is physically impossible.

Many perpetual motion machines fail because the design inherently requires more energy to run than the system contains, and once the initial store is used up the output will end. Such devices are said to fail the first law of thermodynamics, a specific case of the law of conservation of energy. Other designs are based on the conversion of energy from one form to another, or the use of different energy levels from which work can be extracted. The second law of thermodynamics demonstrates that all such process are inherently lossy, and these systems will leak away energy and eventually stop.

Perpetual motion, in the strict sense of the term, is theoretically possible. The galaxies in the universe will move forever, by any practical definition, but no work is being extracted so they are not machines. Likewise, there are any number of common examples of machines that run for long times; a hydropower dam produces electricity from a seemingly endless supply of water, but the water is being provided by an enormous evaporation process powered by the Sun. It is important to contrast these examples with the concept of a perpetual motion machine in the sense that it is used here.

Despite the fact that successful perpetual motion devices are impossible in terms of the laws of physics, the pursuit of perpetual motion remains popular. Modern examples often claim to comply with both laws of thermodynamics but access energy from obscure source. These are sometimes referred to as perpetual motion machines, although they also do not meet the criteria for the name.


 * The Websters-online-dictionary.org link is busted. That site itself now identifies as totodefinition.com, and does not have an entry for the phrase "perpetual motion". If we're looking for lay-language definition (or meta-search of several other lay-reader sites), maybe ? DMacks (talk) 04:48, 19 October 2014 (UTC)


 * Metric expansion of space is a different thing than objects themselves simply/actually physically moving apart. Dark energy describes itself as some sort of field or type of energy that causes the acceleration; therefore there is energy input involved, which contradicts the definition. I don't know enough about this topic to figure out what would happen (or if it's knowable, or even reasonable to ask) to the motion if the effect of dark energy were removed ("would it be perpetual even without it?"). DMacks (talk) 04:48, 19 October 2014 (UTC)


 * And astronomers differ about what will happen at the end of the Universe. A major possibility is the heat death of the universe, in which everything "runs down".   Rather than debate cosmology, the introduction should make the point that all these systems are losing energy to friction or other losses, so they cannot continue moving "perpetually". -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * Which is a useless definition of perpetual in this context, and I admonish myself for saying anything because I knew it would turn into this sort of definitional BS. Maury Markowitz
 * "...but no work is being extracted so they are not machines."
 * This is characteristic of all perpetual motion machines of the 3rd kind, they serve as energy-storage devices, yet most are still called "machines". You would not call a gyroscope or a superconductive magnet a "machine"? -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * Sure you would, if they perform work. What do you think the definition of a machine is? Maury Markowitz
 * Both gyroscopes and superconductive magnets have been used to store energy and when the energy is extracted they do work, but by your definition if they are not producing work they would not be called "machines". I don't see that thermodynamics makes this distinction between "perpetual motion" and a "perpetual motion machine". Any system which has the potential to produce work indefinitely (or in the case of machines of the 3rd kind, store energy indefinitely) could be a "perpetual motion machine". -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:13, 19 October 2014 (UTC)
 * "Perpetual motion, in the strict sense of the term, is theoretically possible."
 * Unless you can find enough WP:RSs to refute the many sources that say perpetual motion is impossible, this can't be included. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * Newton's First Law of Motion: "An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force." Every counterexample being offered here is a practical counterexample, hand waving at its worst... "well, eventually it will hit something". However, that lies outside the definition in the article as that is clearly an external source, and has no basis in the underlying physics. This is why it is vital that the idea of perpetual motion, and the concept of a perpetual motion machine should be clearly separated. Maury Markowitz
 * But you can't find a system in physics which is not acted on by an outside force. The above statement would require WP:RSs that "perpetual motion" is different from a "perpetual motion machine", and that perpetual motion is possible.  I don't see significant support in physics for this view. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:40, 19 October 2014 (UTC)
 * "The Browning Ratchet doesn't work because of the 2nd law, that simply tells you that you're probably not looking hard enough."
 * No, that's the wonderful thing about the thermodynamics laws. You don't have to look further. No machine, regardless of construction, can produce work from a system at equilibrium.   That's what we're trying to get across to readers.  The reason they fail is not due to their individual construction, but to general laws.  The text does make this point but it needs to be clearer. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * The article goes on to explain a twelve year hunt for the actual mechanism. Why do you think they bothered then?Maury Markowitz (talk) 12:33, 19 October 2014 (UTC)
 * From the article: "Any proposed perpetual motion design offers a potentially instructive challenge to physicists: one is certain that it cannot work, so one must explain how it fails to work. ...during that twelve-year period scientists did not believe that the machine was possible. They were merely unaware of the exact mechanism by which it would inevitably fail." -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:40, 19 October 2014 (UTC)
 * "a perpetual motion machine, a device that continues to operate with no external inputs while producing useful work."
 * Again, this is sloppy. It is a machine that continues to produce work without any external energy input. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * Fine, energy. Maury Markowitz
 * ...the first law of thermodynamics, a specific case of the law of conservation of energy."
 * The first law of thermodynamics is the law of conservation of energy. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * No its not, or we would call it that. It is a specific sub-case of conservation of energy expressed in thermodynamics terms. Navel oranges are a type of orange, they are not equivalent to oranges. Maury Markowitz
 * My feeling is that this could be a good introduction, but the errors and misleading statements have to be corrected. It needs to be clear for the non-technically-educated readers. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 13:07, 19 October 2014 (UTC)
 * What, like a completely unsupported statement about apparent perpetual motion in superconductors, which then tries to explain it away but utterly fails to do so? Maury Markowitz
 * I agree the present introduction is lousy.-- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:13, 19 October 2014 (UTC)
 * The most important thing is that it has to state in no uncertain terms that perpetual motion is impossible, due to the two thermodynamics laws. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 06:26, 19 October 2014 (UTC)
 * No, the most important thing is to state in no uncertain terms that perpetual motion 'machines are impossible, due to the two thermodynamics laws. These laws say nothing whatsoever about motion. Maury Markowitz (talk) 12:33, 19 October 2014 (UTC)


 * I personally don't think the lede needs all of these descriptions of "this isn't p.m. because x, that isn't p.m. because y". If you want a quick fix, it could be vastly improved by simply truncating it after "... (as occurs in energy harvesting)."
 * But for a better fix: the lede is supposed to summarize the article. The content and sequence of the lede, after the opening sentence, should be at least closely guided by that of the article body. Go through the article and start with one sentence per level two and level three section, then augment as necessary. If that doesn't produce a good lede, then the problem is not with the lede, it's with the article. Jeh (talk) 10:07, 19 October 2014 (UTC)
 * Whoa, logic to the rescue! Maury Markowitz (talk) 12:33, 19 October 2014 (UTC)
 * Yes, that could work. But I don't see a distinction in the article between "perpetual motion" and "perpetual motion machines", or anywhere that it says perpetual motion is possible. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 14:13, 19 October 2014 (UTC)

Magnets
I have previously attempted to show that the reason the article gives for why the magnetic perpetual motion machine wouldn't work is incorrect. (See Talk:Perpetual motion/Archive 3.) It didn't really get anywhere, so let's try again:
 * The seemingly mysterious ability of magnets to influence motion at a distance without any apparent energy source has long appealed to inventors. One of the earliest examples of a magnetic motor was proposed by Wilkins and has been widely copied since: it consists of a ramp with a magnet at the top, which pulled a metal ball up the ramp. Near the magnet was a small hole that was supposed to allow the ball to drop under the ramp and return to the bottom, where a flap allowed it to return to the top again. The device simply could not work: any magnet strong enough to pull the ball up the ramp would necessarily be too powerful to allow it to drop through the hole. Faced with this problem, more modern versions typically use a series of ramps and magnets, positioned so the ball is to be handed off from one magnet to another as it moves. The problem remains the same.

I believe that the highlighted sentence is inaccurate. (I see that it doesn't cite any references.)

Imagine a closed ramp, of whatever shape, and without magnets. If we put a ball at the top and give it an initial impulse, then - barring friction - it will return to the initial point. (Of course, you can't extract energy from such a machine; it just changes potential energy of the ball into kinetic energy, and vice versa. Gravity is not a source of energy.)

What happens if you add magnets to the ramp? Turns out, nothing much. Magnets are not a source of energy, either. The only difference they make is changing the value of the potential along the path of the ramp; there's still a point of the maximum potential where, if we place the ball and give it an initial impulse, it will theoretically make a full circle.

The argument the article gives is correct, to a point. If we place the ball anywhere and it starts spontaneously moving, it is by definition not at the point of maximum potential, and cannot make a full circle - for the same reason as if we place the ball at a slope (without magnets), it can't make a full circle, either: it doesn't have enough potential energy to reach the top of the ramp. (Of course, this assumes that the ball is initially at rest.) But it's NOT correct as stated, which can be easily shown.

Imagine a ramp shaped as in the schema below: M

.|   / |   /  |  /   | *    | \____/ If the ball weighs one kilogram, the force needed to pull it in vertically up is almost 10 Newtons. What prevents me from placing the magnet such that at point. it pulls the ball with the force of 9 Newtons? The force needed to pull a ball on an inclined plane is proportionally less, so if the ramp is diagonal, if I place the ball near the point ., it will roll up, then fall down the hole. It is true that the magnetic force decreases with the distance - but if the ramp is nearly horizontal at the starting point *, the force needed to pull the ball along it can be made arbitrarily small, barring friction. (Also, I could use a very strong magnet and place it far away from the device, reducing the gradient.)

We can see that under idealized conditions and given a carefully constructed ramp, if we place the ball at point *, it will roll up and then fall down; so the reason the article gives is incorrect. It still won't be able to complete a full circle; the point of maximum potential is not *. (I believe that such a ramp would have minimum potential somewhere near the start of the right bend of the bottom ramp, and maximum potential somewhere on its left bend close to point *.) But this is still a technicality: if we give the ball a sufficient initial speed, or start at the true point of maximum potential and give it an arbitrarily small initial impulse, it WILL make a complete circle. (No matter how unintuitive it seems, we could also push the ball to the right, and it would cycle in the opposite direction.)

So why the machine wouldn't work? As demonstrated above, it's not because "any magnet strong enough to pull the ball up the ramp would necessarily be too powerful to allow it to drop through the hole". Rather, it's for two reasons: Mike Rosoft (talk) 06:38, 24 May 2015 (UTC)
 * Friction and other dissipative forces would soon stop the machine; and
 * Even without friction, the machine could not do any work due to the law of conservation of energy; it would just change potential energy into kinetic energy and vice versa. Neither magnets nor gravity is a source of energy.


 * The integral of the magnetic force on any object over any closed path, in any magnetic field, is zero. That's really all that needs to be said. Jeh (talk) 06:47, 24 May 2015 (UTC)
 * That's essentially the law of conservation of energy, correct? (As I have said, a magnetic field is not a source of energy.) - Mike Rosoft (talk) 15:30, 24 May 2015 (UTC)
 * Yes, it is because the magnetic field is a conservative field; it conserves energy. The above is the definition of a conservative field.  The other fundamental fields of physics, the electric field and the gravitational field, are also conservative fields; any machine that works on any combination of these fields cannot be a perpetual motion machine.   You can see that any machine that works in a cyclic motion cannot gain any energy from the field, because each of its parts, when it returns to its original position after a cycle will have the same amount of energy as before.


 * In your magnet example above, the total potential energy of the ball is the sum of its magnetic potential energy and gravitational potential energy. You could draw lines of constant total potential energy on your drawing above, similar to contour lines on a map.  There will be a minimum (a potential "well") at the magnet pole, and another along the ground level.  Between the two there will be a curving "ridge" or "saddle" line of maximum potential energy.  If the ball is started in a stationary state, whichever side of the ridge it is started on it must stay on that side; it does not have the energy to cross it.  If it is started above the line on the magnet side it will end up at the magnet pole, while if it is started below the line it will end up at ground level directly under the magnet.  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 19:13, 24 May 2015 (UTC)


 * Mike Rosoft is right, and while the comments from Jeh and Chetvorno also contain correct statements about the physics, neither of them answers Mike's essential point. A magnet which was strong enough to pull the ball up the ramp would, in an ideal situation without friction, air resistance etc, give the ball enough kinetic energy for the ball to go flying past the magnet, and, if there was no floor underneath, the ball would then drop down under gravity. Of course the device wouldn't work, but for the usual reasons why perpetual motions don't work, namely losses due to friction etc, not due to the magnet's not letting the ball drop. I shall edit the article to remove the erroneous statement. The editor who uses the pseudonym "JamesBWatson" (talk) 13:39, 29 May 2015 (UTC)
 * Hmm. When I wrote the above message, I intended to replace the incorrect statement with a better one, but when I tried to think out a better one, I could not think of a suitable concise statement of what the true problem is, so I have just removed the wrong explanation, leaving "The device simply could not work" without any explanation. Not at all satisfactory: can anyone do better? The editor who uses the pseudonym "JamesBWatson" (talk) 13:48, 29 May 2015 (UTC)


 * There are many possible trajectories but they all end with the ball stationary at one of the two potential energy minima in the problem; either at the magnet's pole or on the bottom ramp directly under the magnet. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 21:27, 29 May 2015 (UTC)

Perpetual motion
Perpetual motion is not Impossible but inevitable. I give you to you perpetual motion. Its far to easy to explain and I guess only a abstract mind would find it. The age old idea of turning a water wheel with a Archimedes screw. Works! if you float the entire thing underwater. And give it mercury run on. Chuxgold. — Preceding unsigned comment added by 172.78.220.253 (talk) 05:07, 25 September 2015 (UTC)
 * No it doesn't, but that's beside the point. This is not a place for abstract discussions of perpetual motion, but rather a place to discuss improvements to the article KaturianKaturian 18:56, 27 September 2015 (UTC)
 * Putting the whole setup underwater would only create more friction. Water is a more viscous fluid than air. Your machine will stop moving even sooner.202.73.1.98 (talk) 09:54, 17 November 2015 (UTC)

even enduring physical objects are ultimately transient
I have altered parts of the lead. A dictionary is not an adequate source for this kind of definition, because a dictionary reflects the wide usage of words, including unencyclopedic usages.

Atoms continue to move even when they are elements of an isolated system. What does not continue is not their motion, but, rather, is the forms and motions of enduring physical objects that they constitute.

The idea of "the heat death of the universe" is an obsolete nineteenth century speculation that goes far beyond present scientific knowledge. The long-term future of the universe is not known to present-day science, and is not strictly relevant to the concept of perpetual motion. A Wikipedia article is not in general a reliable source.Chjoaygame (talk) 22:54, 7 December 2015 (UTC)

Blackbird 'see also' edit
I have undone an edit that added a 'see also' link to a land sailing vehicle. The story of the vehicle sounds remarkable and interesting, but it is not a perpetual motion machine. Perhaps it may lead to something that might intend to be a perpetual motion machine, and that would make it relevant to this page. But at present it hasn't got to that point. Perhaps others may think I am wrong to have undone this edit, and they will undo my undo. Let's see.Chjoaygame (talk) 10:56, 12 January 2016 (UTC)


 * I support the reversion. Sailing upwind has nothing to do with perpetual motion. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 12:22, 12 January 2016 (UTC)


 * Support this isn't an article about counterintuition, though perpetual motion does fall under that category, too. Rklawton (talk) 15:38, 12 January 2016 (UTC)


 * (Just for fun. For it to make sense that the speed of the Blackbird exceeds the wind speed, one needs to include the ground (or some other thing) as a reference. The windmill blades must collect energy from the wind and this energy must be made to move the vehicle relative to the ground. The vehicle's wheels must exert traction on the ground. On this argument, the Blackbird seems possible if the windmill blades are adequate.Chjoaygame (talk) 16:17, 12 January 2016 (UTC))


 * It's powered by wind, which is just sun power once removed. Sailing upwind, whether in a boat or in a wheeled vehicle, whether by tacking with conventional sails or by tying a boat's propeller or cart's drive wheels to a windmill, is no great trick. And for such a windmill-powered cart to "exceed the wind speed" could be just a matter of gearing, assuming that the windmill fan blades are big enough. It has nothing to do with perpetual motion. CoE does not say anything about velocity; as long as the energy extracted from the wind is greater than the k.e. added to the cart, plus losses, you're on the right side of the laws of t.d. Conservation of energy and the laws of thermodynamics (loosely: You can't win; you can't break even; you can't even quit the game) do not prohibit the cart's motion from having greater velocity than the wind. They only require that the k.e. energy of the cart, plus the inevitable losses, can't be greater than what you extract from the wind. Jeh (talk) 04:21, 19 January 2016 (UTC) (Edited per Ch.'s comment below.) Jeh (talk) 11:01, 19 January 2016 (UTC)


 * For people like me, CoE means conservation of energy. But you need also to comply with the second law to be on the right side of the laws of thermodynamics.Chjoaygame (talk) 07:20, 19 January 2016 (UTC)


 * I agree. I was going for clever wording and ended up with the wrong wording. Edited. Jeh (talk) 11:01, 19 January 2016 (UTC)


 * How I imagine it working is an electric car that has a turbine, behind the grill, that catches the wind and converts it to electricity with an electric generator. There would be side vents and a bottom vent for max air flow.  The car would need to generate just over 20Kilowatts  for it to be "Perpetual".  I've pitched it a few times over the years to Apple Inc.  Wikideas.jpeg Kcida10 (talk) (Uploads) 11:43, 30 January 2016


 * Yeah. You might try to find out just how big your wind turbine would have to be, and how fast it would have to spin, to generate 20 kW. Jeh (talk) 18:09, 21 February 2016 (UTC)


 * I think that is far more complicated than necessary, even missing the point entirely. All you need is very good gears (no friction) and a big and efficient windmill.Chjoaygame (talk) 06:38, 31 January 2016 (UTC)


 * I have undone a repeated posting that I undid as at the start of this thread. Now there is a further reason to undo it. The above comment by Editor Kcida10 indicates the posting as commercial promotion.Chjoaygame (talk) 16:11, 21 February 2016 (UTC)

Is there a bot for detecting 'softening' words?
I've made a few edits to the Perpetual Motion article in the last couple of months, all of which have the same gist -- removing inappropriate 'softening' of statements, e.g.


 * A claim that planets spin "almost indefinitely", which is to say that they can NOT spin indefinitely (https://en.wikipedia.org/w/index.php?title=Perpetual_motion&diff=prev&oldid=704876694)
 * A claim that that conversion of some kinds of energy "could in principle operate with 100% efficiency, but only if they were to be free of friction", which is to say that they could NOT operate with 100% efficiency. (https://en.wikipedia.org/w/index.php?title=Perpetual_motion&diff=next&oldid=705201026)

That second one was particularly egregious, since the principle being discussed is the 2nd Law of Thermodynamics, so that sentence claims "Perfect conversion of energy is in principle possible, except that it violates the principle of energy conversion."

In ordinary use, those sorts of softening words are used to convey things like "a very long time" or "a very high degree of efficiency", but in an article about infinite time horizons and 100% efficiency, those same softening words obscure the fact that the meaning of the sentence is the reverse of what the softening seems to convey.

I think I've removed most examples of this, but it made me wonder if there are any automated tools to look for this particular use of words like "almost", "seemingly", "practically", "in principle" and flag them for review? cshirky (talk) 03:08, 13 March 2016 (UTC)

"Interesting" advert about 6 pages long published about 30 years ago in New Scientist
Around 30 years ago there was an interesting advert in New Scientist about a perpetual motion machine.

Someone believed he could build a perpetual motion machine, tried to publish it in all the usual journals (Nature etc), but naturally the editors of the journals refused to publish this. The guy got frustrated, and took out several pages of advertising space in New Scientist, where he described the principle in a lengthy "scientific paper". It was really heavy on maths, and I never understood it, but I know one of the assumptions made was that c is not a constant. He reckoned c changed depending on whether the earth was moving towards or away from the sun. He could measure that change, but nobody else could, as his equipment was more accurate. Somehow this was going to be exploited to make a perpetual motion machine.

He wrote that he believed he would have a perpetual motion machine built in about 5 years. Needless to say, we have long since past that time, and he not got it working.

I wonder if anyone recalls that advert, or has a copy of it? Drkirkby (talk) 19:58, 14 March 2017 (UTC)
 * A library near me has their back issues of New Scientist as bound volumes rather than electronic. Can you narrow down the timeframe any better? DMacks (talk) 21:06, 14 March 2017 (UTC)

Some eternal engines
1. https://en.wikipedia.org/wiki/Foucault_pendulum based engine will work as long as Earth will rotate since it is not a realm of TD. 2. Magnetic field based rotors, since you need only to align magnetic poles correctly in order to force some massive wheel to rotate forever (or as long as magnetic field will maintain its strength, i.e. as long as the particle possessing it will be present and not destructed). This type of engine would be truly eternal and working on its own without additional input. 3. Earth's magnetic field can be exploited too like in the case of gyroscope (it is purely gravitational effect, but it can be made to generate and magnetic field which interaction with Earth's magnetic field would be larger than the energy required to spin the wheel called rotor). 4. Synthesis of elements and consequent splitting (exactly like our Universe is working...and yes Universe is infinite in both: time and space), since it is subthermodynamical realm of particles. This one is truly eternal too, just hardly manageable due to the requirement of huge masses in order to work. — Preceding unsigned comment added by 134.7.193.46 (talk) 05:38, 29 July 2016 (UTC)


 * All wrong, I'm afraid. btw, "thermodynamics" in the more general sense is not solely about heat. It's about energy in general. And all evidence is that it absolutely is conserved, even in quantum-level interactions. Jeh (talk) 21:43, 14 March 2017 (UTC)

feel free to make the article talk nonsense
Perpetual motion refers to ordinary bodies such as wheels and cogs. It doesn't refer to things so small that one cannot see them individually. At the level of atoms, the notion of friction has disappeared. Feel free to make nonsense of the lead by not making that clear. The second sentence of the lead is also wrong. Perpetual motion of the second kind doesn't do work, it just keeps going. The laws of thermodynamics hardly apply to motions such as the orbiting of planets, because they are far from thermodynamic equilibrium, and gravity on large scales is not within the scope of established thermodynamics. And feel free to talk about grammar when you mean style.Chjoaygame (talk) 20:32, 18 March 2016 (UTC)
 * There are several editors involved here. I'll address my changes. First, the article does not appear to address very small (atomic) scale as being different, or the requirement that an object must be macroscopic and observable individually to be able to discuss them. Another editor tagged the scale requirement as cn, which is reasonable. Note that you removed that tag without providing reference, merely stating "ordinary language". Given that the article itself doesn't appear to address the issue at all, I removed it altogether because WP:LEAD advises "Apart from basic facts, significant information should not appear in the lead if it is not covered in the remainder of the article", and the scale restriction is not an obvious or basic and undisputable fact. Atomic collisions and other interactions and lots of zero-point-energy perpetual motion machine fantasies all do agree with perpetual motion in a closed system not happening even at atomic level (and it's easy to find some RS that agree ). It's true that friction isn't a useful concept to discuss at atomic level, but that is not the only mode energy dissipation discussed in the article. As to my "grammar" change, I did not think perpetual motion is an object or countable entity, so I removed the indefinite article. That's also in keeping with the rest of the article that discusses this as a concept rather than an event. DMacks (talk) 20:55, 18 March 2016 (UTC)


 * Perpetual motions were schemes for wanna-be practical devices, dreamed up before there was practical evidence for the reality of atoms. They were not philosophical speculations about the inner workings of atoms. The choice of the default meaning, whether it assumed the existence and relevance of atoms, or did not, is a matter for common sense and context. Scale universality is not an obvious or basic and indisputable fact. The article does not address the inner workings of atoms, and it is natural to assume it is not referring to them. I think Democritus didn't think of atoms as having internal planets like motions; that was Bohr's invention, I think. Today one might ask about electron orbits and whatnot, but that is an anachronistic sophistication. It seems clever, of course. There were many perpetual motion schemes.Chjoaygame (talk) 13:18, 10 May 2016 (UTC)Chjoaygame (talk) 14:05, 10 May 2016 (UTC)


 * I agree that the lead was nonsensical in claiming that perpetual motion was impossible altogether. All atoms above absolute zero vibrate incessantly; that's what heat is.  It's better to leave out absolute claims which seem more likely to confuse than inform and so I have removed the offending sentence. Andrew D. (talk) 20:50, 15 March 2017 (UTC)
 * I agree with Chjoaygame's position, at least with regard to atomic motion; it certainly should not be included. The word "perpetual motion" was coined before the concepts of energy or thermal motion were understood; what it meant was macroscopic motion, useful motion, work.  That is the current meaning of the term "perpetual motion" in physics: either energy from nothing, or (p. m. of the 3rd kind) macroscopic motion without friction or loss.  The definition must be based on WP:reliable sources, and I don't see any that include atomic motion, , ,   -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 03:23, 16 March 2017 (UTC)

What about atoms?
Specifically, electrons orbiting a nucleus. It's not a machine or anything artificial, but does their motion continue forever? Or at some point (theoretically) they reach maximum entropy, something causes them to stop. Can this mean something moving forever, rather than just a machine, an object moving through space will go forever, unless some other force acts on it, stops it. The snare (talk) 05:01, 10 May 2016 (UTC)
 * They don't "orbit" in anything close to the planetary sense of that word. Our article on atomic theory discusses the evolution of scientific understanding of the nature of electronic behavior near a nucleus. DMacks (talk) 05:17, 10 May 2016 (UTC)
 * it is known for at least 100 years that electrons do not rotate around nucleus and that is why Pauling developed the notion of orbitals, but even this notion is not properly understood by some (it is the positions in space that can be occupied by electron, but electron is just hanging in one position depending on distribution of electromagnetic forces between nuclei and him or within one nucleus between all electrons and parental nucleus) — Preceding unsigned comment added by 134.7.193.46 (talk) 06:15, 29 July 2016 (UTC)

My understanding: Yes the electrons are in "motion" (they have energy), with the electron appearing in different places every time that it is observed. One can take energy out the atom until it reaches its lowest energy state, whereupon no more energy can be taken out, but the electron, even in its lowest energy state, still has some energy. So, the ground-state atom is in "perpetual motion", but it is not a "machine" that can be used to accomplish some sort of work. Correct me if I'm wrong about this. Isambard Kingdom (talk) 12:57, 19 March 2017 (UTC)

Thermodynamics cover only the part of Physics
it deals only with motion of particles due to T (it is caused by combined action of gravitational and EM fields, but indirectly), but not with the motion which is attributed to direct field's action on a matter...in this way exists not only the eternal motion, but and the eternal engine (it is actually the obvious fact since if exist an eternal motion, then must be and work done by this motion - eternal work)...so laws of thermodynamics are governing not all physical processes, but only temperature cycles...however the 1st law of TD is not the law of TD but general law of everything, since it is states that nothing appears from nothing...and the 2nd law of TD is actually again the general law of physics directly derived from the first and governs the differences in energy sizes (the most energetically favorable is minimal energy rather than higher energy).

The first law of Thermodynamics is a consequence of the conservation of Energy. Which according to Noether's theorem, it boils down to the time translation symmetry of Physics' laws. So, no it isn't a general law that says that "nothing appears from nothing". The second law isn't derived from the first, and it has nothing to do with energy sizes, but with entropy; that is the quality of each energy quantity. Finally, both laws are very strong and can be found in all parts of Physics (big/small scales, fast/slow speeds). Mlliarm (talk) 22:17, 24 June 2017 (UTC)

Time crystals are not perpetual motion machines.
They're driven. Adding citations that don't back up your claim does not make it any less wrong.
 * I agree that they are not "perpetual motion machines" and do not violate the laws of thermodynamics;, the current paragraph is not supported by the sources. Time crystals fit the literal definition of "perpetual motion", but because energy cannot be extracted from the motion - they are in the quantum "ground state" of minimum energy - they do not fit the modern definition of "perpetual motion machine" as a device which produces or stores energy perpetually.  This is not because they are "driven", or are an "open system" as stated in the current text, but because their "motion" does not represent energy at all; they possess "motion without energy".  For the same reason they do not violate the first or second laws of thermodynamics.  The paragraph needs to be rewritten. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 22:15, 19 September 2017 (UTC)

Artificial Water Cycle
How about if you used the water cycle, of water evaporating and condensing on large scale in a closed system? Where evaporation is caused by heating, then the water condenses, and while it condenses at a high height it is allowed to pass down like a hydro electric systems, to pass through hydro electric turbines to come down to be evaporated again. This can result in a cycle of perpetual motion. — Preceding unsigned comment added by Susanscottish (talk • contribs) 12:25, 12 November 2018 (UTC)
 * No, the second law of thermodynamics says that all closed-cycle systems are irreversible, which means that some of the energy is lost to the environment as they operate. A system such as you describe has many sources of energy loss: friction of the turbines, electric resistance in the wires, aerodynamic drag of moving water vapor, viscous drag of the moving water flowing through pipes, radiation of heat released by the condensing water, etc.  The water cycle on Earth requires a constant huge input of heat from the Sun, which is dissipated into the environment. --Chetvorno<i style="color: Purple;">TALK</i> 13:14, 12 November 2018 (UTC)

PMMs of the third kind
I think we should add that PMMs of the third kind are the only kind that aren't strictly forbidden, that is they are at least not technically impossible in principle (in contrast, machines of the first and second kind are strictly forbidden even just in principle). In practice, dissipative forces will always exist in any system where degrees of freedom are neglected, and so PMMs of the third kind aren't feasible beyond simple isolated systems at the atomic level. Also if they were possible in practice, they would only be useful as a form of energy storage. They could not be used as a source of energy generation. 132.160.70.36 (talk) 03:22, 30 October 2019 (UTC)

Woodward's wheel
F.G.Woodward's hoop wheel that is supported by two rollers is an interesting try. It should be included. 95.178.135.0 (talk) 22:11, 12 May 2020 (UTC)

"Robert George Adams" listed at Redirects for discussion
A discussion is taking place to address the redirect Robert George Adams. The discussion will occur at Redirects for discussion/Log/2021 November 30 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Leschnei (talk) 14:03, 30 November 2021 (UTC)
 * The discussion also includes Adams motor and Adams Motor. Jay (talk) 03:50, 8 December 2021 (UTC)