Why perpetual motion free energy machines don't work

It still amazes me that with all our posts dedicated to trying to help homeowners save energy, our most popular posts are on free energy scams (mainly magniwork and hojo motor).  I've gone back and forth with the energy ignorant in the comment section of these posts, but I've never written a post dedicated to explaining why these products just won't work.  This post is speaking to those who are confused about perpetual motion devices that claim to create more energy than they consume.  If you notice in the title, I state they "don't" work, not that they "won't" work.  They don't work according to the existing laws of physics.  The future is unknowable. Perpetual motion devices have been attempted for as long as man started making complicated machinery. The goal of many unfortunate inventors  has been to create a machine that will produce useful work in a closed loop system, or in a system without any external forces.  Donald Simanek maintains an excellent history at attempts to create perpetual motion devices in his Museum of Unworkable Devices. In scientific terms, perpetual motion devices are impossible under the current laws of thermodynamics.   Being humans with tiny little brains, our understanding of the universe is limited, so there is always the possibility that the laws of physics will expand and/or change over time.  But as the laws currently exist, the two that are most frequently cited regarding perpetual motion devices are the first and second law of thermodynamics.  In summary (quotes attributed to C.P. Snow):

  1. First law of thermodynamics - Conservation of energy.  Energy can be transformed from one form to another, but it can't be created or destroyed.  "You cannot win (that is, you cannot get something for nothing, because matter and energy are conserved)."
  2. Second law of thermodynamics - Entropy. Systems always flow to a state of disorder.  "You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases)."{C}{C}{C}{C}{C}{C}

Wikipedia classifies the different categories of perpetual motion devices as follows: "One classification of perpetual motion machines refers to the particular law of thermodynamics the machines purport to violate:

  • A perpetual motion machine of the first kind produces work without the input of energy. It thus violates the first law of thermodynamics: the law of conservation of energy.
  • A perpetual motion machine of the second kind is a machine which spontaneously converts thermal energy into mechanical work. When the thermal energy is equivalent to the work done, this does not violate the law of conservation of energy. However it does violate the more subtle second law of thermodynamics (see also entropy). The signature of a perpetual motion machine of the second kind is that there is only one heat reservoir involved, which is being spontaneously cooled without involving a transfer of heat to a cooler reservoir. This conversion of heat into useful work, without any side effect, is impossible, according to the second law of thermodynamics.

A more obscure category is a perpetual motion machine of the third kind, usually (but not always)defined as one that completely eliminates friction and other dissipative forces, to maintain motion forever (due to its mass inertia). Third in this case refers solely to the position in the above classification scheme, not the third law of thermodynamics. Although it is impossible to make such a machine, as dissipation can never be 100% eliminated in a mechanical system, it is nevertheless possible to get very close to this ideal (see examples in the Low Friction section). Such a machine would not serve as a source of energy but would have utility as a perpetual energy storage device."

In summary, here are reasons why perpetual motion energy generation devices don't work:

Conservation of Energy - Say the law of conservation of energy wasn't a law.  You create a perpetual motion device that somehow overcomes all of the external forces mentioned above and you have a device that can operate itself perpetually (similar to the perpetual motion machine of the second kind listed above).  Now, your device can operate forever, but how can you extract any work from it?  If you take energy out of your machine, you will slow it down!  And no, magnets don't "create" energy, they just create a propulsion force.  To make magnets do work you have to add energy (i.e. spin them). I'm not sure I can spend too much time on this one point, because this is ultimately at the heart of perpetual motion energy generation machines.  If someone claims they can get energy out of a system, that energy has to come from SOMEWHERE!  It can come from the sun (nuclear), wind (which is created by the sun), gravity (one way trip), coal/natural gas/oil (dead organisms initially powered by sun), nuclear, humans (powered by food which is powered by sun), etc.  ENERGY HAS TO COME FROM SOMEWHERE. There is no free lunch. Now, there is this tiny little issue of dark energy (also mentioned at the end of this post), but it is outside the scope of this discussion because I don't know too many inventors claiming their perpetual motion device operates on dark energy.

Friction and external forces - This is really an expansion of the law of conservation of energy. Friction occurs when molecules of one thing come in contact with molecules of another thing.  Rub your hands together and feel heat generated.  That heat is energy leaving your body.  Anything operating on Earth will encounter external forces. Thought exercise time!  Think about driving your car down a flat highway.  Bring your car up to speed.  Go ahead, whatever speed you want, there is no speed limit here.  Now take your foot off the accelerator.  What happens?  You car is going to slow down and eventually stop because of air resistance (or friction between the air outside and the body of your car), rolling resistance between your tires and the road (or friction between asphalt and rubber) because gravity (external force) is pulling your car towards the earth, and the internal friction between all the working parts of your car (pistons, wheel bearings, crank shaft, etc.). Ok, we're done with the cute little thought exercise.  Now imagine that car is some perpetual motion machine.  Guess what, all those external forces are still there!

Entropy - This is the hardest to explain but it is also the most obvious.  Basically, everything in the universe wants to go to a state of disorder. Buildings don't build themselves, and when they're built, they eventualy fall down.  Heat always flows from hot to cold. Everything dies.  Everything falls apart.  Maybe one day the universe will start collapsing in on itself, time will reverse itself, and this won't be the case.  But in the known lifespan of the universe (13.75 billion years) entropy has always (100% of the time) increased.   A perpetual motion machine would result in no net disorder, which has never happened in 13.75 billion years.  Not a fan of history dictating future, that's fine, how are you going to get past conservation of energy? Michio Kaku (who graduated first in his Harvard physics class, received his doctorate from Berkeley, and taught at Princeton) addresses perpetual motion machines in chapter 14 of his excellent book Physics of the Impossible.  In his book, Kaku breaks down "impossible" into three classes (summarized below):

  • Class 1 impossibility - impossible today but do not violate known laws of physics
  • Class 2 impossibility - technologies that sit at the edge of our understanding.  If possible, they may be realized thousands or millions of years in the future
  • Class 3 impossibility - technologies that violate the known laws of physics.  If possible, these technologies would represent a shift in our understanding of physics

Kaku labels perpetual motion a Class 3 impossibility (teleportation and telepathy are Class 1, time machines are a Class 2).  He states in the closing of chapter 14 on perpetual motion:

Because creating a true perpetual motion machine may require us to reevaluate the fundamental laws of physics on a cosmological scale, I would rank perpetual motion machines as a Class III impossibility; that is, either they are truly impossible, or we would need to fundamentally change our understanding of fundamental physics on a cosmological scale in order to make such a machine possible.  Dark energy remains one of the greatest unfinished chapters in modern science

Do you understand why I'm referencing this?  An expert in theoretical physics labels perpetual motion as 1 of only 2 class 3 impossibilities in all of theoretical physics (the other being precognition). Finally, I must address a claim that I see all the time regarding free energy devices.  Conspiracy theorists claim that the big bad energy companies are suppressing free energy devices because it will destroy their profits.  This is complete and utter rubbish. Let me tell you how I would get around this issue if I had stumbled on the greatest discovery in all of history:

  1. Chronicle my discovery in exhausting detail.  Paper, electronic, pictures, videos, etc.  Create hard copies and store them with trusted love ones.  Email electronic copies to email addresses I make up on multiple different hosts.  Take out multiple safety deposit boxes in many different states/countries and store identical copies of my research in each one.
  2. Create a company whose purpose is to build and sell my device or power from my device.  Make sure to find a good attorney to ensure all legal work is in proper order.  Getting a good attorney is critical.
  3. Go to investors/universities/press and demonstrate my findings.  Sell shares of my company if capital is needed.  Venture capital guys are pretty good at making money on any kind of idea, there is no need to go to the energy companies.
  4. Become the richest and most famous person in the world while alleviating many of the world's problems.

How could the big bad energy companies hurt my plan?  They couldn't.  Nobody can stop someone else who has a powerful idea.  Sure, the person who created the idea could be murdered, but if step 1 is followed properly, the idea still lives on. Would you really fear death if you had the idea to change the lives of 7 billion people?  Blaming large energy corporations is the cowards excuse for why his/her favorite perpetual motion device won't work.  Of interesting note is Andrea Rossi and his cold fusion energy generator.  Rossi seems to be following the steps above, and is in the middle of step 3.  We'll see if the device (which is not perpetual motion, but is cheap, clean energy) works or not.  Hopefully he reaches step 4. Hopefully you now understand why perpetual motions machines won't work according to the existing laws of thermodynamics.  Could the future change and could dark energy provide unlimited power?  Sure it can, but until then, machines will never operate perpetually, much less create free energy. End of story.


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Interesting while I don't believe in perpetual motion devices and it could be very likely the the hojo motor is a scam. I do however believe in free energy devices. With everything always moving from things as small as as an atom to the solar system galaxies etc.. Everything is always giving off energy in some form and this energy is in abundance all around us from the oceans to the moon to the sun to cosmic radiation from the big bang. Its just finding the most efficient way to capture the energy. It would be ideal to capture energy form sources that exert energy in abundance for billions of years such as our sun, "In one second, our sun produces enough energy for almost 500,000 years of the current needs of our so-called civilization" Then we have cosmic radiation from the big bang, super novas, quasars and so on. Basically I'm saying there is enough energy out there and even here to supply our electrical needs freely for our foreseeable future. The only problem being is efficient ways to harness the energies obviously solar, wind, hydro are not sustainable in its current format because the costs of maintenance, upkeep and such. We know its out there and its very obtainable its just a matter of finding the best and most efficient way of capturing it. IMO there should be a drive towards this if everyone including governments corporations and such were so serious about wanting alternative energies and to tap that energy and not being so reliant on fossil fuels then they would put together something similar to xprize offering millions to anyone who can tap into this free energy and prove it through scientific verification I for one would donate money to a prize for anyone finding a way to harness these energies for the good of all... Just a thought.
You have just re-invented hydro-electric power. See for example the three gorges dam in China.
Dearest Maliki, You have got a really big heart! Please, please, please be very careful with your money. Those of us that create .... do so not for monetary gain. The Creation is the Reward. I am fascinated with your point of view and I have many other things to say to you; but as I am a very slow composer of messages, I wanted to get this message to you first and foremost.
Dearest Maliki, If I understand you correctly, the operative phrase in your message is: "harness these energies for the good of all…". I agree with this sentiment 100%. The problem, as I see it, is to offer a solution that can be used in every location on the globe without interference by any man-made entity; whether that entity be a government, a corporation, a religious organization or any other that man may dream up. Furthermore, I think we have to alter our approach to the problem/solution and embrace a motto of "simplify, simplify, simplify". We cannot continue to swim in a sea of perpetual energy (the universe) and still deny the possibility of a perpetual machine. We cannot continue to view the splitting of energy formations in our machines as a "loss" and yet, in the very next breath, claim that energy/mass cannot be created or destroyed. If we position a waterwheel in a river, can we still claim that the portion of the river that did not interact with our wheel is a "loss"? If you think that this is a valid point of view, please let me know. If you do not, please let me know that as well. I do welcome your response, either way.
ericsongs, your example of the 2 magnets in a vertical tube repulsing each other does not demonstrate any WORK done. It is just a balance of forces (i.e. Newton's 3rd law) between the repulsion force of the magnet and the gravitational force acting on the mass of the upper magnet. WORK is done on an object when a force acts to move said object through a DISPLACEMENT. In your example no NET WORK was done. Yes you could bring the magnets together and when you released them they would repel each other and we say that the magnetic force did some WORK on one of the magnets to move it through that displacement. But you had to do an equal amount of WORK in the first place to bring them together against the magentic repulsion force. So I don't think any reader with some basic understanding of physics was confused by Pk's post. Chris is absolutely correct.
ericsongs, we swim in a sea of perpetual energy but this energy has not only a quantity but also a quality. This is the corallary of the second law of thermodynamics which Chris has explained in his initial post (albeit in simplified terms). 100 Joules of heat energy is less useful than 100 Joules of electricty insofar as its capacity to produce work. That 100 Joules of electricity can be easily converted into 100 Joules of heat but not so the other way around. You won't get 100 Joules of electricity from 100 Joules of heat - there will be losses in the conversion process. Also, heat at higher temperatures is more useful (lower entropy) than heat at lower temperatures (higher entropy). Unfortunately, the way the universe works (at least to our current understanding) is that it is always moving towards a state of higher entropy, i.e. there are irreversibilities. Some say this is what gives direction to time. Philosophically, you could say this is what gives meaning to life. So with regards to the perpetual motion machine, it really is impossible by our current understanding of how the universe works (I really like Michio Kaku's definition of the different classes of impossibility). Those who would claim otherwise inevitably fall short of demonstrating their new understanding of the universe and proving the validity thereof... "We cannot continue to view the splitting of energy formations in our machines as a “loss” and yet, in the very next breath, claim that energy/mass cannot be created or destroyed" We call it a "loss" when energy is converted irreversibly into a lower "quality" form (i.e. higher entropy). The second law does not violate the first law of thermodynamics. Energy/mass cannot be created or destroyed. Recommended reading: Fundamentals of Engineering Thermodynamics by Michael J. Moran, and Howard N. Shapiro. Cheers and keep searching for the truth.
Dearest YooWee, First: Let me thank you for your thoughtful response. Second: I would like to clear up a possible misconception. My poorly worded comments may have given you the impression that I find fault with the axiom that "energy/mass cannot be created or destroyed." I believe that to be absolutely correct. You stated that "So with regards to the perpetual motion machine, it really is impossible by our current understanding of how the universe works ..." I find this to be be the crux of the our disagreement. I do not think we understand as much as we think we do. 100 joules = 100 joules except when it doesn't? If 100 joules thermal does not equal 100 joules electric, perhaps our formula needs to be amended or altered in such a way that "A" = "A". You also stated "We call it a “loss” when energy is converted irreversibly into a lower “quality” form (i.e. higher entropy). The second law does not violate the first law of thermodynamics." I am not yet convinced that this second law could possibly be true, given the first law, just because We Say So! It seems much more likely that mass must coalesce after entropy just as entropy must follow coalescence; perhaps by a methodology that has so far eluded our observation, perhaps by a methodology that we have misinterpreted, and the cycle completed. I say this because Xuepeng Chen at Yale has documented the event. (see the following link) What follows below is a partial transcription of the opening of the video "David Talbott and Wallace Thornhill - Thunderbolts of the Gods [© KRONIA GROUP 2006]" The earth was the center of the universe - It was flat. Then it was round, and it circled the sun. It was no longer the center of the universe, it was a tiny part of the Milky Way. The Milky Way was the only galaxy. Except it wasn’t - It was only one of billions of galaxies, floating in space without end. Every single time we think we’ve got it all figured out, we realize we’ve merely found another piece of the picture. It is a big picture, with many pieces. Sir Isaac Newton was the first to state the Law of Gravity. Eventually everybody agreed that gravity alone formed galaxies and stars and planets - And that gravity alone holds the universe together. Then we discovered a force a thousand billion billion billion billion times more powerful than gravity. (10^35) Until recently we believed the space between the stars and planets was empty, a vacuum. We now know it is teeming with charged particles. We see glowing electric filaments spanning thousands of light years - We see stellar and galactic formations shaped by magnetic fields. Only electric currents can create magnetic fields. Is it possible the predominant force is not gravity, but something else? Recommended viewing: Cheers and keep searching for the truth.
Dearest JooWee, Please forgive me for not seeing this entry earlier. I am not being notified by this site via email, even though I have checked the box at the bottom of the page everytime I posted. Additionally, I ask your forgiveness for misspelling your name in my other response to you. That was completely unintentional and I regret it very much. As far as the magnets are concerned, I think I see your point. Said point being that the upper magnet would not move any distance at all. Opposing the force of gravity does not count, correct? Would it therefore also be correct that: if I was holding a 200 pound set of barbells above my head for two minutes until my arms were quivering so much that I had to release and let it fall to the floor, that I only performed work for the two seconds that it took me to lift the weight to a distance above my head? And once again, exerting an opposing force to the force of gravity does not count, correct? (or do I still not get it?)
Hi ericsongs, no worries about the misspelling. You have almost got it. When you say "opposing the force of gravity does not count, correct?" my counter-question would be "count towards what?". I am guessing you mean count towards WORK done. The answer is WORK is done when ANY force acts to move an object over a DISPLACEMENT (or distance). Whether it is with or against gravity is irrelevant insofar as work done is concerned. When an apple falls to the ground from a tree, the work is done BY gravity. "If I was holding a 200 pound set of barbells above my head for two minutes until my arms were quivering so much that I had to release and let it fall to the floor, that I only performed work for the two seconds that it took me to lift the weight to a distance above my head?" Yes that is exactly correct. The only work you did was to lift those barbells from the ground to above your head. If I anticipate your next question correctly, is would be something like this - "if I'm not doing any work, why then am I getting tired and my arms quivering?". I was sure someone else had already explained this (and did a better job at it than I could have) so here goes: Please don't think I'm being condescending when I say this is basic high school physics, because it really is. Although the above explanations can be found in any high school physics textbook, I have taken the time to explain it again here because I think it is important that we learn to differentiate the real thing from the pseudoscience of Perpetual Motion Machines. Scams such as HoJo Motor and Magniwork prey on our innate yearning for something better to make a quick buck. Not that we should stop yearning for something better, but let's arm ourselves with the knowledge to discern fact from fiction. This does not mean fiction may not someday become fact, just that some are more improbable than others. Right now, perpetual motion machines are about as improbable as it gets and the burden of proof is on those who would tell you otherwise. Although I would like nothing more than to see them succeed, so far, they have all failed. Cheers!
ckmapawatt's picture
You performed work to lift the barbells above your head, and then you applied a force to the barbells once they were there. Of course since your arms are quivering (moving) you are also performing work.


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