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The Perpetual Quest


Dimitry Rotstein

Skeptical Inquirer Volume 35.5, September/October 2011

How to make a perpetual motion device and live to tell about it.

Once upon a time, at the tender age of ten, I was playing with a magnet and an empty tin can. Suddenly I noticed that if I moved the magnet away from the can, with the distance between them remaining the same, the can rolled faster and faster in its pursuit of the magnet. But what if the can was rigged to the magnet, I thought? Obviously, the device would continue accelerating, without the aid of any outside force, at least until it hit the nearest wall. Three pencils and some duct tape were enough to constrain the magnet in front of the can at the desired distance. But to my great dismay, the resulting system remained completely motionless.

Undoubtedly, many people of the inventive type can relate to this experience—thinking up a seemingly ingenious idea for making a system that generates persistent motion with no energy source. Recorded propositions for building similar contraptions, usually called perpetual motion devices1 or perpetuum mobile (PM for short), date back to at least the seventh century CE (Peter 2004). A plethora of mechanisms based on such ideas have been designed and built, ranging from the stunningly trivial to the ridiculously complex. Different though they may be, all share one common quality: much like my “magnetic can,” they do not work.

Only in the nineteenth century were the culprits behind this perpetual failure (pun intended) discovered. These are the relentless laws of physics, or more specifically, the first and second laws of thermodynamics. One would expect that ever since these laws were established (with solid theoretical and overwhelming experimental basis), PMs would have become history. Surprisingly, that hasn’t happened. In fact, even at the beginning of the twenty-first century, the PM “industry” isn’t just alive and well but, arguably, more popular than ever before. And it’s not just the “modern” kinds of PMs, like “zero-point modules”2 or “torsion field generators,”3 but the most classical ones too—the “overunity devices,”4 which violate the first law of thermodynamics. In fact, at you can see a grown man playing with magnets in almost the same way I did as a child. This is just one example, but many more exist. The forum at alone lists more than 25,000 members (as of December 2010), most of whom describe themselves as overunity inventors, and YouTube contains hundreds, if not thousands, of videos showing supposedly working PMs of all kinds. And the numbers keep growing.

Of course, such a high interest in PMs is easily understandable. In light of the global energy crisis, pollution, and human-induced climate change, an inventor of a free and clean energy source would certainly become rich and famous beyond imagination. On the other hand, centuries of utter failure and PMs’ scientifically proven impossibility should serve as an overwhelming demotivator. So, how can all these people still believe in PMs—and not just believe but waste a lot of time and effort in trying to build such machines?

There are several possible explanations. As the famous case of John Keely suggests (“Keely’s Secret” 1899), some of the “inventors” of PMs might well be frauds who are looking for an overly naive investor or just seeking publicity. Others are simply ignorant about the abovementioned impediments, especially at first. But, judging from various forum discussions, the majority appear to be honest and knowledgeable in this particular field. These people sustain their beliefs in the manner typical of most pseudoscientists—by denying the validity of scientific laws (Choronzon 1991) and by postulating a grand conspiracy theory, which might explain all the seeming failures. According to this theory, working PMs are not only possible, but they have already been built and the truth has been suppressed for various reasons and by various means, ranging from hostile discouragement to physical elimination of the invention along with its inventor (Bearden 2009).

Of course, thorough arguments have been mounted against conspiracy theories in general and this one in particular (Volkay 2007). But overall, a good skeptic should rely on testable facts rather than abstract arguments as much as possible, no matter how well reasoned these arguments are. Fortunately, testing conspiracy theories—at least this particular one—isn’t difficult (albeit potentially lethal if the conspiracy theorists are correct), and I have done exactly that on two separate occasions.

The first opportunity came along in November 2007, during an annual technological competition called BizTec. Competitors had to submit a description of some novel invention of their own to be judged by a panel composed of industrialists, venture capitalists, and academic staff. The best proposals in terms of practicability, innovation, and commercialization would get a cash prize, but I was only interested in the judges’ reaction to my proposal. According to the contest rules, every submitted idea—no matter how silly—would receive thorough feedback. For my submission I selected one of my own designs, which I had come up with awhile back. At the time of its conception, I even believed it was a valid idea for a short while before I realized it was just another PM. (It’s so hard to criticize your own ideas.)

A plate, holes upFigure 1. The “flying saucer”—or rather a plate (holes up).

The idea is pretty straightforward. Imagine a simple saucer lying on a table. Both sides of the saucer are subjected to a constant and equal air pressure, so it doesn’t move. But the air pressure is caused by the air molecules randomly bouncing off the saucer’s surfaces. Now, suppose that the saucer’s lower surface was shaped (on a microscopic level) in such a way as to reflect the air molecules in some specific direction rather than randomly. Then, the air pressure on this surface might be different from normal. Even if the pressure changed only by one percent, the resulting difference would be enough to lift the saucer itself, as well as a two-pound weight attached to it, off the table. Of course, this principle isn’t new—it’s just an unusual variation of an old PM concept known as Maxwell’s demon, except that my PM doesn’t have any moving parts. Richard Feynman showed that Maxwell’s demon cannot work (Feynman et al. 1963), but his proof applies only to the moving trapdoors of the PM. So my design, having no moving parts, does appear to have a fighting chance of working; provided, of course, that we throw away the second law of thermodynamics, which explicitly forbids energy extraction from a static pressure.

According to the conspiracy folks, the judges at the competition, after seeing my proposal, had to make sure that I wouldn’t build such a device. At best, they’d just laugh at my idea until I gave up and threw it away in frustration. At worst, they’d call the Men in Black to erase my memory or even my very existence. Needless to say, I’d prefer the first option. But their actual response was something I wasn’t expecting at all: of some 150 submissions, ten received a $1,000 prize, my “flying saucer” being among those ten! The promised feedback was also quite encouraging. In all fairness, some judges did express their doubts that such a device could work, but they all liked the idea.

My experience is far from unique. Just a few months after the BizTec competition, designer Clay Moulton made headlines after winning a similar competition with his “gravity lamp” concept: a 600- to 800-lumen light source powered for a period of four hours by a slowly descending 50- to 100-pound weight (Moulton 2008). Simple high-school-level calculations show that these requirements correspond to the device having an efficiency of far beyond one hundred percent.

My second opportunity to test the conspiracy theory hypothesis came along a year after the BizTec competition. As part of my graduate training, I had to design and implement a laboratory experiment. Even though I came up with a few other interesting ideas, I decided to present my “flying saucer” first, again just to test the reaction of the professor in charge of the lab (hopefully not the “morph into an alien and devour me” kind of reaction). I was in for another surprise. Professor Yakov Krasik, the professor in charge, became excited about the idea and decided to go forward with it. Being a seasoned physicist, he of course recognized a PM at once, but that didn’t seem to bother him. So we started building our “flying saucer.”

Due to financial constraints, we couldn’t reshape the surface on a microscopic level, so instead we made a macroscopic array of conic holes to concentrate the reflecting air molecules. Computer simulations showed that this should work,5 provided that the air molecules didn’t collide with each other while inside the holes (which would randomize their trajectories, destroying the alleged concentrating effect). To meet this condition, we put the whole contraption into a vacuum chamber and reduced the air pressure until the mean free path6 of the air molecules became larger than the size of the holes (at about 10,000 times less than the normal air pressure). According to simulations, even under such low pressure the lifting force would be strong enough to be detected by high-precision scales. The experimental setting is shown in figures 1 and 2.

vacuum chamber and saucerFigure 2. Vacuum chamber with the test “saucer” on the scales.

It should be noted that I only ran the experiment after I personally tested the equipment to make sure that neither High Cabal nor Illuminati agents had messed with it. Naturally, there was no measurable difference in the plate’s weight—with the holes facing up or down—at any pressure. Of course, if the results had been positive, then the second law of thermodynamics would fly out of the window faster than any flying saucer. Science prevailed once again when the saucer failed to work.

However, to my great surprise, Professor Krasik was genuinely disappointed by the negative result. I asked him whether he really believed this experiment could possibly have worked. After all, I told him right from the start that it couldn’t, and I thought we were on the same page. This was his response: “I was almost sure that nothing [would] be positive, but … life is [a] complicated thing—and the more I’m working, the more I understand that not all what I know, or what I studied, is correct” (ellipsis in the original). Now, dear reader, I ask you this: does that really sound to you like someone who is trying to suppress anything? To me it surely doesn’t.

No, I can definitely say that I have found no attempt at conspiracy. So, if no one has been able to build a working PM over the centuries, then perhaps the devices are indeed useless. Well, maybe useless isn’t the proper word here. After all, a PM has already earned me (despite myself) a thousand dollars, some lab experience, and this journal publication. But do PMs really work or could they even possibly work? There’s not much chance of that, I’m afraid.

Some may point out that a few isolated examples don’t constitute a thorough study, and they’d be right. However, it takes only one whistleblower to expose a conspiracy (if it exists) and only one small hole in the wall of pigheadedness to push a radical idea through (if it’s valid). I have discovered two such holes in the first two places that happened to come along. Not even once have I encountered any hostility or ridicule of the kind that PM proponents claim to suffer. If anything, my experience shows that the academy and the industry are more lenient toward PMs than they should be. This observation probably doesn’t apply to most scientists and engineers, but the level of acceptance for PMs that I’ve witnessed is still surprising—if not troubling. As for the more extreme conspiratorial ideas, there is the undeniable fact that as I write these lines, I’m still very much alive.


1. The term perpetual motion device is actually a misnomer because the existence of perpetual motion is assured by Newton’s first law. a more proper name would be perpetual motor (still abbreviated PM), because the idea is to generate useful work from the perpetual motion, whereas the real perpetually moving object is useless in this respect. If you try to produce work from its motion, it will cease to move as soon as its initial kinetic energy is depleted.

2. The zero-point module (ZPM) is a hypothetical device that can utilize vacuum energy. According to quantum field theory, each point in space contains an enormous, perhaps even infinite, amount of energy. However, there is no scientifically plausible way to harness this energy, at least not without violating the existing laws of physics. Although some PM inventors claim to have constructed devices that use vacuum energy, the whole ZPM concept is regarded as pseudoscience or, at best, science fiction.

3. Torsion field theory, originally put forward by a few Soviet scientists, postulates an existence of fields unknown to science with amazing properties, among which is the ability to produce unlimited energy, antigravity, and faster-than-light travel. The theory (and resulting devices) is generally considered to be pure nonsense.

4. An overunity device is any system that produces more useful energy than it consumes. In technical terms, this means that its energy efficiency is greater than one or unity (i.e., more than 100 percent), hence the name “overunity.” Such devices would obviously violate the law of energy conservation (the first law of thermodynamics) and thus are scientifically impossible.

5. It was discovered later that one of the formulas for the simulation was missing a sine factor, which explains the false-positive result. Of course it was obvious from the start (at least to me) that a simulation that produces nonphysical results must be flawed.

6. The mean free path is the average distance that an air molecule traverses before hitting another molecule. At normal air pressure, it’s less than one-tenth of a micron. Reduced air pressure means fewer molecules flying around, hence the increase in the mean free path.


Bearden, Tom. 2009. Suppression of The MEG. Public correspondence, February 11. Available online at

Choronzon, Frater. 1991. Perpetuum mobile: An assessment of the ‘laws of thermodynamics’ from a Gödelian viewpoint. Available online at

Feynman, Richard, Robert Leighton, and Matthew Sands. 1963. Ratchet and prawl. In The Feynman Lectures on Physics. Reading, MA: Addison-Wesley.

Keely’s secret disclosed. 1899. The New York Times (January 20). Available online at

Moulton, Clay. 2008. Gravia. Greener Gadgets Design Competition 2008. Available online at

Peter, Hans. 2004. Perpetuum mobile: Concepts I. Available online at

Volkay, Chris. 2007. Is this article on conspiracies part of a conspiracy? Skeptical Inquirer 31(5) (September/October): 44–46.

Dimitry Rotstein

Dimitry Rotstein, a graduate physics student at the Israel Institute of Technology, has had a lifelong interest in inventions and entrepreneurship, and became a self-styled investigator of "alternative medicine" after being duped by its practitioners one time too many.