Why are you so infatuating?
As a kid I used to think about perpetual motion all the time, and by a kid, I mean 10ish, and by all the time, I mean when I saw magnets. Because magnets are cool.
I knew it was impossible, I didn’t quite fully know why, but I knew it was unachievable. Something about laws of physics, I’d think, but it still didn’t mean I did not think about perpetual motion.
(I mean technically we are on about the Laws of Thermodynamics but I was 10 and what 10 year old knows about the Laws of Thermodynamics?)
Then, later when a teacher would bring out magnets in class, dreams of perpetual motion would come flooding back into my head again.
“But look!” I’d think as I snapped magnets together, or magically repelled another magnet across the table.
“If I can do this, then surely we could make a machine that does this endlessly?”
Forgetting of course, that it is my hand that is moving the magnet that repels the other, and forgetting again, further still, about those Laws of Thermodynamics, that I did not understand in the slightest. Who is it who made those laws? Newton, Joule, Carnot? I did not know. I was 10. I would be lying if I said I had heard of any of them, other than Newton and even then I’d heard of him because of something about an apple, not magnets.
And then, like we all do at that age, full of childlike arrogance, you doubt everyone else: “I wonder if anyone has ever even thought about magnets? I mean perpetual motion cannot work, but did they think about magnetic perpetual machines?”
They had, of course they had, LOTS of people had and still do today.
But the simple reason is they can never exist. None of them. They break our laws of physics and will never work. Hell, even if somehow (which you cannot), make a machine that spins eternally and perpetually be in motion. How are you planning on getting the energy out of it anyway? No matter which path you take there will ALWAYS be a stumbling block. Friction kills perpetual motion. Air resistance kills perpetual motion. Entropy kills perpetual motion.
Every moment that passes on your spinning magical disk, something is acting against it. It’s potential energy output grows lesser every moment. Simply put it starts wearing down as soon as you even turn it on. Even more simply put, it starts wearing down before you even turn it on!
So maybe you can make a perpetual motion machine, but because of those forces acting against it, your machine will forever be in debt to the forces of the universe. Energy will be lost through friction and every turn will make it harder and harder to even beat something as simple as the air resistance acting upon it.
Therefore, every tiny force acting against your machine, is a much larger issue to solve.
I mean who, in society, cares about friction? Obviously there are a lot of people who care about friction (for example mechanical engineers) but in everyday life who really cares? When I go to shop, friction, air resistance, entropy, gravity and the vector fields of magnets, do not really bother me and I’m going to hazard a guess they do not really bother you either. They seem so small and so inconsequential. They are all happening, but we cannot feel them. Well, these are just some of the things that will stop your perpetual motion machine dead. Good luck trying to beat any of them without putting more energy in than what you get out.
But let’s ignore science for a moment. Let’s say perpetual motion is possible and the universal laws of physics have allowed us a way to create it (good luck beating the second law of thermodynamics though because entropy dictates the more energy transferred/transformed the more that is wasted and even a closed system will descend into disorder and therefore waste energy).
What’s a simple way to know that perpetual motion cannot exist?
Well, do you not think we would have already discovered it?
I know this sounds a simple argument but let’s for a moment take a look at what you get when you search YouTube for perpetual motion machines.
Firstly however, ignore the conspiracy theories that suggest the government are hiding perpetual motion from us (…Yawn).
What else do you get?
Well, you get a lot of machines that people say they have invented and they are going to demonstrate them to you. They always start by giving them a push (I thought this was perpetual motion? Why does it need a push?) and they always say they have had this running in their shed for 3 months non-stop (no evidence of course but it’s not like they have a camera filming right now that they could of used to record it, but oh well).
(And just a side note, if I push a K’Nex Ferris Wheel and it literally doesn’t stop turning because I added some magnets to it. I’m not waiting 3 months to tell the world. I’m going to know pretty sharply if I’ve actually achieved the impossible).
But you know what else you get? Well, you just have to look at the machines. They probably have magnets, or they probably are overbalanced buckets of water, or they are just simply water based, or they likely involve some kind of ball bearing, running down a track and somehow magically manage to get back to the start to do it all over again.
Basically, there are a lot of them, and usually they are some kind of variance on the theme of something being overbalanced and this overbalancing causes (usually a wheel) to turn round with the weight of the bucket hanging from one of its spokes and then this bucket of water causes the wheel to turn enough that the next bucket of water gets to the position the original bucket was in and then the weight of that causes the wheel to turn and so the next bucket gets to the position (and so on and so on).
Or it is something with magnets, roughly doing the same thing, but anyway I’ve digressed: What do you see with these machines? Well, they are all so incredibly basic.
I know this sounds harsh but I mean, buckets of water? Ball bearings? Magnets? It’s hardly rocket science is it? It’s stuff we have had access to for centuries, nay, millennia.
And further to this point, we have been clever for a long time. Very clever. For example, the Greek polymath Eratosthenes (c 276BC — 194BC), quite accurately estimated the Earth’s circumference and its axial tilt. Aristarchus of Samos first proposed the Earth moves around the Sun in the 3rd century BC. The Ancient Greeks also invented showers and vending machines and this is just small part of history and a small part of what the Greeks did. There has been many civilisations with many many smart men and women and none of them discovered perpetual motion.
I know this sounds like a silly argument but if these guys could not discover perpetual motion, then how is Gary the 47 year old bricklayer in his shed going to discover it with basically the same technology that those Ancient Greeks (or the many smart people who followed) also had? (i.e. with a bucket of water, some string and an overbalanced wheel). He isn’t.
So guys, we should just stop being perpetual motion shed dreamers and we should go do something more useful with magnets and do some magnet fishing instead, because who knows we might find a bike!