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Evidence into Practice Join other followers. Sign me up. Already have a WordPress. Log in now. Loading Comments Email Required Name Required Website. Simply put, the First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another.
A perpetual motion machine would have to produce work without energy input. The Second Law of Thermodynamics states that that an isolated system will move toward a state of disorder. Additionally, the more energy is transformed, the more of it is wasted.
A perpetual motion machine would have to have energy that was never wasted and never moved toward a disordered state. Still, the inviolability of the laws of physics has not stopped the curious from ignoring them or trying to break them. According to Simanek's online museum, the first documented perpetual motion machines included a wheel created by Indian author Bhaskara in the 12th century.
It supposedly kept spinning due to an imbalance created by containers of mercury around its rim. Other attempts include a 16th-century windmill, 17th-century siphons, and several water mills.
While most perpetual motion attempts have been in the spirit of scientific inquiry, others have aimed to deceive and make money.
The most famous perpetual motion hoax was devised by Charles Redheffer in Redheffer's perpetual motion machine enthralled the Philadelphia and New York communities and brought in thousands of dollars. It was debunked twice by engineers, which ultimately led to Redheffer being run out of town, according to " Perpetual Motion: The History of an Obsession " Adventures Unlimited, by Arthur W. Nineteenth-century America was a prime time for hoaxes. According to Kimbrew McLeod, author of " Pranksters: Making Mischief in the Modern World " NYU Press, , the Age of Enlightenment's focus on science, learning and gaining knowledge through personal experience and observation led increasing numbers of people to seek out phenomena that they could judge for themselves.
Additionally, increasing literacy rates meant that more people were familiar with concepts like perpetual motion and were eager to see a machine that achieved it. But, as Barbara Franco wrote in " The Cardiff Giant: A Hundred Year Old Hoax ," "people were interested in the new sciences without really understanding them … The nineteenth century public often failed to make a distinction between popular and serious studies of subjects. They heard lectures, attended theaters, went to curiosity museums, the circus and revival meetings with much the same enthusiasm.
People seem to enjoy being taken in by a story that they know might be untrue, falling for it anyway and then being surprised upon learning they were duped. That Redheffer was actually run out of town suggests that early s audiences perhaps hadn't yet fully embraced that form of entertainment, though they would in subsequent decades. Historians do not know Redheffer's background prior to the hoax, according to Ord-Hume. He appeared on the scene in when he opened a house near the Schuylkill River for public viewing.
Inside was a machine he claimed could keep moving forever without ever being touched or otherwise aided. Redheffer's machine was based on an "assumed 'principle' of perpetual motion that assumes continual downward force on an inclined plane can produce a continual horizontal force component," said Simanek.
The machine had a gravity-driven pendulum with a large horizontal gear on the bottom, according to Ord-Hume. Another, smaller gear interlocked with the larger one.
Both the large gear and the shaft were able to rotate separately. Placed on the gear were two ramps, and on the ramps were weights. The weights were supposed to push the large gear away from the shaft, and the friction would cause the shaft and gear to spin. The spinning gear would, in turn, power the interlocked smaller gear. The water then flows down streams to lakes or oceans, where radiant energy from the sun evaporates some of it and atmospheric circulation also sun-driven moves it elsewhere and dumps it as rain.
Some of that rain falls at higher land elevations, forming streams which power waterwheels, and so on.
This is a cyclic process, but not a closed one. It requires energy input from the sun. And gravity, though necessary to the process, is not a source of energy. The energy came from the sun. The fact that gravity is not diminished by all of our machinery, space satellites, etc. Now some things may steal a bit of energy from the rotating earth they'd have to be pretty massive events , slowing it slightly. But that doesn't come from the earth's gravity and it doesn't diminish the earth's gravitational strength.
The gravitational strength of the earth is strictly dependent on the mass of the earth. Gravity is always directed toward the center of the earth. We can get energy from the wind with windmills. Couldn't we make a gravity windmill to extract that energy that is blowing toward the earth? This is a very old, and mistaken notion, going back to the 17 th century at least. As I said above, a gravity field is a mathematical model, not anything material, and field lines pointing toward the earth do not represent a "flow" of anything.
The error here is to use a false analogy between gravity and wind. I know people today who still think a gravity windmill is possible, but I won't name names. But don't magnets have unlimited stored energy? A refrigerator magnet will support itself on the wall of the refrigerator forever, continually exerting force against gravity to keep itself from falling.
So isn't it capable of unlimited work? So I suppose the nail driven into the wall is also doing unlimited work supporting the picture frame hanging from it? I have heard the "refrigerator magnet" example from many people over the years, and find it incredible that they can so confidently make this absurd claim without even thinking of obvious counter-examples. Force and work are different things. Work requires motion. A force that produces no motion does no work, and consumes no energy.
Some magnet motor and magnet engine proposals have continually moving magnets. Can't these extract energy stored in the magnets? Permanent magnets are used in motors and generators worldwide, and none of these machines ever extracts any energy from their magnets. The magnets merely facilitate the conversion of mechanical to electrical energy or vice versa. After many years of operation, the permanent magnets in these devices still retain their original magnetic properties. The stored energy in a magnet is only that due to the magnet's manufacturing process.
It is a small amount. In normal use, the internal stored energy of a magnet is not used or diminished at all. Heating or hammering the magnet can, however, destroy its internal domain alignments, and therefore, its magnetic effect. Besides, if the magnet did "contain" such a tremendous amount of energy, it must have required at least that much energy to manufacture it, and magnets would be far more expensive.
It's irrelevant, but interesting, to consider just how much energy is stored in a small experimenter's magnet. That information isn't easy to find on the web. I was astounded at how small it is, and asked Rick Hoadley to do an independent calculation, which agreed with mine.
The energy stored in an Alnico-5 magnet bar of that size is 1. A typical hair dryer uses Watts while it is running. If, however, you had a similarly sized NdFeB magnet, it could run the same hair dryer for almost 13 ms! Wow, one hair might get dry! So anyone supposing they could "extract" considerable energy from magnets to solve the energy crisis had better rethink the matter.
Is centrifugal force a good energy source? Centrifugal force is a widely misunderstood concept, often badly presented in physics courses. It is not some exotic kind of force found in nature. It is nothing more than a convenient mathematical concept used when physicists and engineers do analysis of rotating systems using non-inertial rotating coordinate systems as the reference for measurremenets.
Forces are never sources of energy. Forces occur when bodies interact, and, if motion of either body occurs, that interaction may result in one body losing energy and the other gaining an equal amount of energy. No energy is ever created from a force. Technically, centrifugal force, Coriolis force and Euler force are called "fictitious" forces that arise from analyzing a system in a non-inertial reference frame.
All physical results are the same as if the system was analyzed in an inertial frame where these fictitious forces are not present. So ficitious forces can never be the "cause" of any physical effect.
I've seen many analyses that show perpetual motion wheels can't work. When they do an analysis of forces and torques, they consider the wheel at rest, showing it is in equilibrium in any position. But if we gave it a push and set it into motion, might it continue motion, undiminished? Shouldn't we do the analysis of it in motion? Static analysis of perpetual motion wheels usually shows that the system is in equilibrium only at certain positions.
If the wheel has N-fold symmetry, then there are N positions of stable static equilibrium and N positions of unstable static equilibrium between them. If set into motion, it can move for a while, with slightly jerky motion, till friction slows it to a stop in one of the positions of stable equilbrium—the same positions we found in the static analysis.
The dynamic analysis can be done, and is more lengthy and difficult—too involved to discuss here. But it reaches the same conclusion.
The wheel will not exhibit continual undiminished motion unless it is spun so fast that it acts as a simple flywheel. How about converting momentum to energy? Momentum and energy are two different concepts, and are not convertible one to the other.
They have different physical dimensions and units. Mathematically, momentum is a vector and energy is a scalar. Energy is conserved in every closed system we have ever studied, and energy is neither created nor destroyed. Momentum is also conserved in such systems, and the two conservation laws represent independent facts about nature. In the early history of physics when these were not yet understood, there was much debate over which was the "better" or "proper" way to describe motion.
This debate was settled in the 17 th century, when we realized that both concepts are necessary to fully describe how mechanical things work and how bodies interact. Many physical problems simply cannot be solved using only one, but not the other, of these concepts.
Both concepts must be used simultaneously. Could we convert angular momentum to linear momentum, or vice versa? Some have tried to convert rotational momentum to linear momentum. The Dean Drive was one such example.
Norman Dean was taken in by a stick-slip friction phenomena that he didn't understand. His device, if it actually worked on the principle he claimed, would violate not only energy conservation but momentum conservation as well. Others still hold out hope of making such a third-law-violation device sometimes called a "reactionless thruster". But most inventors totally ignore momentum of all kinds because they simply don't know anything about it. They may not even realize that the conservation of momentum law is just as solidly established in physics as the conservation of energy law that they generally despise.
Rotational kinetic energy is just ordinary kinetic energy, since kinetic energy is a scalar and does not depend upon the direction of a body's motion or whether the path of a moving body is straight or curved. So there's nothing more to say about that.
Energy, angular momentum and linear momentum are all different beasts. They have separate conservation laws, different dimensions and units, and aren't convertible one to the other. In your analysis of perpetual motion proposals you never include centripetal and centrifugal forces in the math.
Isn't it possible that if you did include them, you could show that the idea could really work after all? I have never seen a perpetual motion machine proposal where it was necessary to deal with centripetal or centrifugal forces in the analysis to conclusively show why the device wouldn't work.
There are usually easier ways. Nor have I ever seen a proposal where the inventor claimed his idea depended on them. But, rest assured, that if you did a full free-body force and torque analysis of the device, the outcome would be the same: the device won't work.
To do that much analysis would be "using a sledgehammer to crack a walnut. Centrifugal force is a "ficitious" force necessary when analyzing a system in a non-inertial coordinate system.
Ficitious forces are never the cause of a physical effect. See my earlier comment about fictitious forces. I've never seen an analysis that includes centrifugal force. Motion creates centrifugal force, so if we give the wheel a push, maybe the centrifugal forces of its movable parts could sustain continual motion of a wheel.
Many people think of centrifugal force as some "new" kind of force that arises because of rotation. This is a common mistake. Centrifugal force is technically called a "fictitious" force because it is not a "real" force existing in nature, but a mathematical gimmick to make calculations simpler when doing a problem in rotating coordinate systems.
The choice of coordinate system does not change the physics. I'd like to build a prototype, but I don't have much money and don't have a machine shop. Nearly all the devices people describe to me can be built from readily available materials with simple tools. Identify the feature of your device that is the reason you think it will work. Isolate that and build a prototype to test it. Suppose your device is a wheel. Most such perpetual wheel devices can be tested in the modified form of a pendulum, easily built with Erector or Meccano parts.
Curiously, very few perpetual motion machine proposals are in the form of pendulums. See Building perpetual motion machines for examples. If you are clever enough to invent such an original device, you should be clever enough to build an inexpensive prototype that would conclusively show whether it works as you expect.
Be aware that some people become so obsessed with an idea that they are blinded to all else. They spend money and time on a quest that leads only to failure. This is especially true if they choose to work in isolation, and never listen to reasonable and informed criticism of their ideas. I've made a wheel with carefully positioned magnets, and it turns continually when I hold another magnet near it in just the right position.
But when I clamp that same magnet in that same position, so I don't have to hold it steady, it doesn't work. Because when you hold the magnet in position, you are supplying the energy by doing physical work on the magnet you are holding.
Typical wheels with magnets have evenly spaced magnets, and as the wheel is turned they don't exert a constant force on the magnet you are holding. You really can't hold the magnet steady, but are continually making small motions to try to keep it steady against the varying attraction and repulsion from the magnets on the wheel.
The work you do against these forces keeps the wheel turning. It's not psychic energy, or any of that sort of moonshine. When you bring the magnet near the wheel, it begins to turn, and this changes the position of the wheel's magnets and the forces they exert on the magnet you are holding.
You sense the motion this force causes and you try to compensate for it in order to keep your magnet in the same position. But there's a slight delay in your muscular response. We frequently see such demonstrations on YouTube, and some people really think they are on the verge of creating a perpetual motion wheel. With just a little more refinement See: Howard Johnson magnet motor.
Also do a web search for the Minato motor. Gullible people sat around a table in a darkened room with their fingers pressing on a small table. They were instructed to try to prevent the table from moving. Sometimes the table moved, often vigorously. Often with a little help from the spiritualist medium who also sat at that table. Sensing slight motion, the sitters would try to prevent the motion, but because of the delay in their responses, they just caused a rocking periodic motion of the table.
Pendulum divination. The string is held by the fingers with the hand relaxed. One of many charts for use with pendulum divination. This has been compared to the ancient "pendulum divination" game of holding a finger ring or mystical-looking pendant on a string suspended from your finger.
It supposedly answers questions by its mode of swing. But there's a difference. In the magnet motors and the table turning the nervous and muscular system response time plays a crucial role. In the pendulum divination game the person holding the pendulum can subconsciously or consciously control the nature of the motion produced with very slight finger motion.
The pendulum has several modes of motion, all with very nearly the same natural frequency. If its support isn't rigid it can switch slowly from one mode to another. Also, seeing a small deviation toward a change of mode, the person holding the string can subtly encourage or discourage that to make the ring "answer" whichever way is desired.
See also Ouija board. Model of the Hamel spinner. A neat version of this perpetual motion deception uses a large steel ball bearing with a ring magnet placed on it, the whole thing resting on a very smooth table. Another magnet is held above, causing the ball bearing to move so that the ring magnet is near the top. The ball bearing may start to rotate slowly, then speed up, as you try to hold the magnet above it in the optimum position. To make this work the magnets' strength, ball bearing weight and ring magnet strength and weight must be balanced.
So the device is a delicate magnet-gyroscope. Perpetual motion machine scam artists have used this in public demonstrations of the "principle" of their motors. All of these work best if the natural rotation period of the physical system matches the natural period of the hand holding the magnet. This is sometimes called "parametric excitation by hand". I've seen this called the Hamel Spinner. For a picture of this toy, see David Hamel spinning device.
Don't fuss too much about the dimensions of the parts, so long as they are in proportion to the diagram. When I first built one I used a relatively weak 1. It worked well. But I was once careless and the ball was yanked up to the magnet, breaking the ring magnet.
The upper magnet need not be a ring magnet. Rodney Brian has done some experimentation on this device. See his video and review. He shows quite persuasively that a the device is not over-unity, b energy from the hands drives it, c the steel ball can be replaced by a glass or plastic ball, and finally d magnets aren't necessary.
The key to the toy's behavior is 1 A round ball, weighted above, rotating about a slightly tilted rotation axis, and 2 slightly out of phase motion of the hand, supplying energy to sustain the toy's motion. Click here to see this effect at work in the Minato motor. Watch Minato's hands "working". There's a simple test to see what is happening. Instead of holding the magnet in the hand, clamp it to a solid support.
Then the wheel, once started, will spin for a long while like a flywheel but eventually slow to a stop. There are many videos of such devices on the web.
I accept that the laws of physics in textbooks are well-tested, valid and correct. But we don't know everything. Maybe there are other laws that we haven't discovered yet that would not contradict other laws, but would allow for perpetual motion or over-unity performance. We could do an "end run" around the existing laws. True, we don't know everything about how nature works. But the very existence of a working over-unity machine running without energy input would violate existing laws—nearly all of them.
If a wheel continually rotates with undimished speed it must be getting energy from somewhere. It is possible that it might be getting energy from some as yet undiscovered source.
If so the machine would be acting as a a detector of that energy source, and we could then study that new phenomena of nature. Can't a machine extract energy from the gravitational field? That is abundant and free. Physicists use the mathematical model of "fields" to help describe situations where bodies exert forces on each other at a distance. This does not say that the field is something that exists in nature.
Many, including some scienetists, find it difficult to wrap their minds around the fact that bodies can exert forces over distance, with no material "stuff" between them. In the 19th century they even postulated such "stuff" in the form of a luminiferous aether that supposededly filled all of space and provided a medium for influences like gravity, and a medium for light to "wave in". Clever experiments were devised to detect the aether and they all failed to find anything.
After Einstein's relativity theory came along, around , the aether dropped out of physics. Relativity resolved the problems that had seemed to support the aether.
Now the aether wasn't needed. Scientists should have learned a lesson there. But some now think of fields in the same way that they thought of the aether. They speak of "energy of the field" as if the field itself contained energy. Well, it does, in a mathematical model. But that doesn't mean that when a body in a gravitational field gains energy from gravitational forces that they are getting that energy "from the field".
The energy comes from the body producing that field, not from something "in space". The same is true for electric and magnetic fields. This is a difficult concept to explain, and many textbooks promote misconceptions about it. Can we use gravitational sheids around parts of a machine to reduce the weight on one side continually to produce perpetual motion? There are no gravitational shields. We know the mathematics of fields very well, and it does not allow such shields. Experiments show that when a massive wall is placed between two massive objects, it only adds to the gravitational fields already there, by simple vector addition.
Now if there were such a thing as negative mass, it might be a different story. But no negative mass has ever been observed, and no experiment even suggests there might be such a thing. What about electric fields? There exist both positive and negative charges. Can we make an electric field shield? Yes, a completely enclosing metal Faraday cage does that.
Charges separate in the metal due to the field, effectively creating a new field that can subtract from the strength of part of the existing field, while adding to the strength of another part of it. No net energy change. This creates an essentially field-free finite region of space. Metal objects placed in a field modify that field, but don't change the total energy of the system, except for the work required to insert the metal into place. Though it is a long story, this doesn't allow perpetual motion of over unity devices.
And so it goes with magnetic fields, though the mathematics is somwewhat different. Might dark energy and dark matter provide unlimited sources of energy?
Dark energy and dark matter are speculative entities for which there is as yet no direct experimental evidence.
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