Perpetual Motion Machines : Could We Ever Build a 'Real' One?
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Is perpetual motion, a fantastic innovation if achieved or the snake oil of physics? Hindsight is always 20/20 as they say. It is easy for us to laugh and ridicule past claims of devices that are supposedly perpetual motion devices. Popular history often places a stigma on such devices as freakish curiosities of engineering. Is this fair given our current knowledge of the world around us? We must at all times remember what former generations knew at the time. This is true for many facets of science and technology.
A good example would be the 'Bishop Wilkins' magnetic perpetual motion machine. It is often claimed that this was created as a gambit to prove the concept. Perhaps, it was actually intended to prove the futility of the quest for the snake oil of physics. We'll look at this later.
Could we ever make a device that operates with absolutely no energy loss? Let's have a look...
What is perpetual motion?
These types of machines are, in effect, devices that move perpetually, they never stop. If you could create one today, set it moving and left it alone it should, in theory, keep moving until the end of days. Right up to the so-called "Big Freeze", that is a very long time away indeed.
The "Big Freeze" is the theoretical end of everything when the universe has expanded so much that it reaches a state of zero thermodynamic free energy. At this point the cosmos will be unable to sustain motion, atoms will be broken apart and generally, everything will be pretty dead. Space and everything in it will reach absolute zero.
This will be a time of eternal, never ending, utter darkness. A nice thought and it's only about 100 trillion years or so away. There are of course a plethora of other theories of the end of everything to take your pick from but my personal favorite is the Big Freeze. Seems fittingly sobering.
But I digress, the most important thing to note is that such a machine would run at least till this point in time.
Not all that glitters is gold or perpetual motion
You will likely find many designs out there on the 'interweb' claiming to be working prototypes or proofs of perpetual motion. Some of these designs certainly do look convincing on first inspection. You could probably develop a design yourself, and if engineered correctly they could also move for all time.
If this could be achieved, it would have enormous implications. You would think they could provide an eternal source of energy, not just unlimited but also free. Or could they?
Sadly, the real world and fundamental physics have other ideas for perpetual motion machines. They are, by definition, impossible. At least given our existing knowledge of physics. It could be possible that new fields and knowledge will present itself in the future and overturn our understanding of physics. We should "never say never", especially in science. Such revelations would prove everything we know as simply wrong and would render most of our observations of the universe non-nonsensical.
If perpetual motion machines aren't impossible, then we could probably say they come as close as you'll get in science. Let us then take a look at some examples and how they might theoretically work.
A perpetual motion stone gathers no moss
We are sure you are familiar with the first law of thermodynamics. This is the law of the conservation of energy. Energy is always conserved and is neither created nor destroyed. You can change its form from one to another, however. For a machine to keep moving the energy given to the system must stay within the system without any losses. This fact alone renders the idea of perpetual motion machines moot.
A true perpetual motion machine must obey the following:
1. Friction must be eliminated. There can be no moving parts that touch each other. Friction would rob the machine of energy by losing it as heat, or light if it gets hot enough. You could make the surfaces of the parts as smooth as possible but there would still be microscopic imperfections that would create friction, even if very small. Whenever two parts rub together, to any extent, heat will be generated. According to the laws of thermodynamics kinetic energy is being converted to heat energy and lost from the system. Not cool, no pun intended, for the proposed perpetual motion machine.
2. The machine must operate inside a vacuum, i.e. no air. Air, like other moving parts, will rub on the moving machine, create friction and create a small, but important loss of energy from the machine. Over time, even if this were the only friction, the machine would lose all of its kinetic energy from this friction. This would take a long time but the machine would grind to a halt long before the end of days.
3. The machine must be silent, absolutely silent. Any sound production is also a loss of energy from the system. This, like the two other points above, would eventually rob the machine of its kinetic energy.
[Image Source: Pixabay]
Behold the wonder of perpetual motion
Even with the proposed inability of perpetual motion to break the laws of physics; curiosity, or is it arrogance, hasn't stopped ambitious inventors from attempting to achieve that.
Simanek's online museum unveils some of the first machines designed by Indian mathematician and astronomer Bhaskara in the 12th Century. The design was such that is supposedly kept spinning due to an imbalance created by containers of mercury around its rim. Other examples include 16th Century windmills, 17th Century siphons and some water wheel designs.
It must be noted that some machine designs have been designed genuinely in the spirit of curiosity and science. Others, on the other hand, are direct attempts to deceive for monetary gain. Probably the most famous hoax being that of Charles Redheffer from 1812. More on this later.
Nineteenth-century America, like anywhere, was a prime location for hoaxes of this kind. In his book "Pranksters: Making Mischief in the Modern World", Kimbrew McLeod reveals to us many people having a go during the Age of Enlightenment. This was an age for the more scrupulous to seek the truth through the scientific method, for others more of a way to make money through pseudo-science. This was a time of ever increasing literacy introducing older, often debunked, ideas. Sound familiar? Ahem, flat earth. What, who said that?
Learn from history or be doomed to repeat it, or enjoy it
The Age of Enlightenment brought fantastic ideas to the people and this sparked great interest, which is great. Sadly for most of this interest came with the very little understanding of them. Barbara Franco writes about this in her book "The Cardiff Giant: A Hundred Year Old Hoax". For the Nineteenth Century public, the distinction between popular and serious disciplines of science was often hard to disseminate. These curious and hungry minds were fed with lectures, theaters, curiosity museums, circuses and revival meetings.
Another interesting trait of humankind is our apparent love for being duped. Amy Reading highlights this in her book "The Mark Inside: A Big Swindle, a Cunning Revenge, and a Small History of the Big Con". Her book concentrates on the American sense of fun. It can, however, be extended to most of us and our lust for apparently impossible. She explains that people love to be taken in by a story they know are not true. They like to fall for it anyway and then appear to be surprised when they learn they've been conned. You can probably think of many other examples in the modern world. "Click Bait" is the first thing that comes to my mind.
Examples, well non-examples of perpetual motion
As previously mentioned, you will stumble across many many claims of perpetual motion devices or machines. Many will look convincing at first, but a closer examination of them will reveal them for what they really are. The snake oil of physics. With any claim, be sure to ask yourself, "where is the energy coming from?".
Without further ado, let's have a closer look at three infamous, often cited, examples:
Philadelphia and New York were enthralled by Mr. Redheffer's perpetual motion machine in 1812. His shows earned him thousands of dollars, a vast sum at the time. If you are interested the story is covered in great detail in W.J.D Ord-Hume's book "Perpetual Motion: The History of an Obsession". According to Hume, historians know very little fo Redheffer's history prior to the hoax. He first appeared on the scene in 1812, opening a house near Schuylkill River to show off his miracle machine.
Redheffer claimed the machine's "gubbins" could keep moving forever without ever being touched or aided.
The machine, apparently, worked through the assumed principle of perpetual motion through continuous downward force on an inclined plane. This, so it was claimed, would produce a continuous horizontal force component. Redheffer, according to Ord-Hume, constructed a machine that operated through a gravity-driven pendulum with a large horizontal gear at the bottom. This interlocked with another smaller gear. These twin gears and the associated shaft rotated separately. Two ramps were placed on the larger gear and on the ramps were also weights. These weights, so it was claimed, pushed the large gear away from the shaft. The resultant friction would cause the gear and shaft to spin.
This spinning gear would power the smaller gear if the weights were removed the machine would grind to a halt. Redheffer was so pleased with his machine that he lobbied the state of Pennsylvania to build a larger one. The State, rather wisely as it turned out, sent two inspectors to investigate the potential investment. This is where Redheffer's plot began to unravel.
[Image Source: Wikimedia Creative Commons]
Perpetual liar in motion
When the inspectors arrived they found the machine in a locked room with a locked door. Redheffer's machine was only visible through a window. One of the inspectors, Nathan Seller, had also brought his son along. The inspector's son noticed that the gears in the machine were not working exactly as declared. The cogs and gears appeared to be worn on the wrong side. This would mean that the shaft, weights and gear were not powering the smaller gear to the side. It seemed, in fact, that the opposite was true.
Nathan believed his son and determined the machine was a hoax. Instead of going public with his hunch, he hired Isaiah Lukens, a local engineer, to build his own version of the machine. The remit was for it to look and "work" as Redheffers's was supposed to. Lukens successfully constructed a similar device with a seemingly solid base and a square piece of glass at the top. The device had four wooden finials that were supposed to be decorative on top of the glass attached to wooden posts.
Liars never prosper
Lukens placed a clockwork motor at the base. One of these finials, was in fact, a winding device. It could provide power for the motor all day long. This motor would turn the shaft and thus, power the gears. Lukens showed Redheffer the replica machine, who was so overwhelmed with the sight of it working, offered money to know how it worked. Sellers and Lukens let the news of the hoax spread rather than confront Redheffer on the spot.
The machine was debunked a second time after which the crowd smelled blood. Realizing this, the crowd went ballistic and destroyed Redheffer's work. Redheffer, understandably made a quick exit, never to be seen again. Here is a model in action, though it is modified slightly from the original design. This machine is a good example of warning from history over claims of creating a perpetual motion machine.
Bishop John Wilkins' perpetual motion device
Bishop John Wilkins, a founder and the first secretary of the British Royal Society compiled a book on "Mathematical Magick". His work coincided with the period in history where "magical arts" were being replaced by the scientific method during the Age of Enlightenment. An age we could barely understand now as mythology was replaced by reason.
Early in 1600, William Gilbert's book "de Magnete" was released. Readers were offered a fascinating account of Gilbert's experiments with magnetic lodestones and introduction to the new field of magnetism. This sparked great enthusiasm and interest in this fledgling field of experimentation. Many, however, misunderstood this mysterious phenomenon. Johannes Kepler attempted to apply the theory to explain the motion of planets, only later to disregard it.
Kepler played with ideas that the sun was a huge magnet whose fields affected the planet's orbits, he later tossed it aside. Anton Mesmer thought that perhaps magnets influenced the human body, thinking that they might create a magnetic influence within people. It is speculated that Anton's work coined the phrase "animal magnetism" and "mesmerism".
Back to the machine
Wilkins discussed the difficulty of achieving perpetual motion. He considered, in detail, a device often attributed by Schott to Johannes Taisnierus. This device consisted of two tilted ramps, an iron ball and magnetic lodestone stuck on the top. The lodestone was a large chunk of natural stone encased in an iron ball.
The ball was pulled up the ramp towards the lodestone, where it later fell through a hole towards a lower ramp. From here, it rolled down through another hole back to the straight ramp where it was pulled up again. This basic concept obviously needed further work and refinement. How do you stop the ball being held in place on the ramp by the magnet for instance? It would be difficult for us today to understand why this device was taken seriously at the time. Even today this basic concept is still considered for contemporary perpetual motion solutions, so-called magnetic motors.
Wilkins considered the device and offered detailed discussion and practical difficulties of the device. His discussion considered a major difficulty being that the ball wouldn't fall all the way down to the lower ramp but be held in place by the magnet. Perhaps it would even ascend from the lower ramp.
Wilkin's machine is a good example of how we should be aware that some proposals could be warning us of the futility of this quest.
The drinking bird
The drinking birds or sipping birds or insatiable birds whatever you want to call them, they are pretty interesting devices. At first, this may seem to be a good contender with its different design than most perpetual motion "engines". These cheeky little party tricks have a bird shaped lever which "takes" a drink and then returns to a vertical position and so on.
How is it doing this? It does indeed look like it is in perpetual motion. The basic design of these "toys" involves two glass bulbs joined by a length of glass tubing. Just over half of space inside the glass bulbs and tube are filled with a fluid and no air, which is usually colored. This liquid is typically dichloromethane or methylene chloride, which has a very low boiling point.
Drinking to oblivion
The head is usually covered in felt, which absorbs water as it "drinks". Evaporation of this water lowers the temperature of the head, causing dichloromethane to condense in the head section. This creates a pressure drop in that section of the apparatus following the ideal gas law. The higher pressure in the tail end pushes liquid up the neck which makes the head section top heavy. Drinking bird then pivots and the head touches the liquid. As this happens, the tail section rises above the surface of the liquid.
Pressure equalizes as a bubble of "warm" vapor rises from the head to the tail, displacing liquid as it goes. This increases the weight of the tail and the bird returns to its vertical position, ready for the whole process to start all over again. So is it a perpetual motion machine? Remember, where is the energy coming from? That's right the ambient air temperature. No, this is not a perpetual motion machine, this teaches us to always look for the energy source if not immediately obvious.
This is the end of the road - Galvatron
So there you go. We hope we've given you a good overview of the wonderous world of perpetual motion. We've explored what such a machine would need to achieve and had a look at some proposals. Clearly, there are many other examples and we encourage you to share the weirdest and wildest ones you can find.
History is filled with hoaxers, snake oil salesman and some genuine individuals with altruistic intents. We should keep an open mind when considering future proposals but be mindful of past claims. Perhaps one day the laws of physics will be overturned by a future innovation in technology. Such technology must be fully investigated rather than taking the creator's word for it, we know you'd never do that of course.
We have seen that past generation can probably be forgiven for their acceptance of past claims of working examples. Our understanding of the world around us is something rare in human history. The less honorable have in the past exploited our innate "need" for perplexion and this should serve as a warning for all of us as we move forward. Staying on point, we should all be alert to this possibility but enjoy the entertainment of "magic". Variety is, indeed, the spice of life.
So you get to build a "forever moving" machine, get it moving by supplying energy to it and then what? That's all the energy you'll ever be able to harvest from it and it won't generate "new" energy for you. So, what's the point, let's be honest, of perpetual motion machines?
We hope you enjoyed this article! We welcome any suggestions of great examples of perpetual motion machines you can find. Why not try to build one yourself?
Sources: LockHavenUniversity, Futurism, Makezine, LiveScience