The Museum of Unworkable Devices 309
Jippy_ writes "The quest for perpetual motion has been going on since at least the 11th century according to this site, and scientists have been getting it wrong ever since. Take a gander at some of the most valiant efforts (and ultimately the biggest failures) in trying to beat the laws of physics through the last 1000 years, along with other impossible inventions and devices."
Atari: Masters of unworkable devices (Score:2, Informative)
I thouht I was terrible at Aliens vs. Predator until I realized I kept getting killed because I was staring at the controller more than I was looking at the game.
Re:Perpetual motion *IS* possible (Score:2, Informative)
More unworkable devices (Score:2, Informative)
The problem with your idea is thermodynamics (Score:5, Informative)
Re:Perpetual motion *IS* possible (Score:1, Informative)
No, because it's radiating energy. It will keep going if you keep putting energy in (which would then make it a non-perpetual motion machine, funny that).
Re:Go Forever? (Score:3, Informative)
A machine must do Work (definition: The transfer of energy from one physical system to another).
Perpetual motion is easy. A perpetual motion machine is impossible.
Simon.
(Getting tired of pointing out that machines have to DO something)
Re:Perpetual Motion Machines of the First Kind (Score:5, Informative)
Re:Weather and other perpetual motion (Score:2, Informative)
Re:First hand experience (Score:3, Informative)
http://www.lhup.edu/~dsimanek/museum/unwork.htm#w
Yes, no, and maybe. (Score:5, Informative)
As for weather, the problem is you're relying on an external power source - the sun. Turn that off, and boom, no weather (well, eventually anyway). You are correct though, we can use this energy that's just sitting around and gain more than we put into something. In fact, this is how our entire planet survives - both its organisms and our modern society. Think hydroelectric damns and wind turbines - they're just using something that's there anyway. And plants take advantage of the ever-present sun to store chemical energy within themselves, which other organisms then use when they eat said plants, etc.
The problem still lies in self-contained systems. A friend of mine took years to believe me that you couldn't run a ship (assuming no wind outside) with windmills powering a motor that actually powers the ship. Friction is a bitch
Re:Perpetual Motion Machines of the First Kind (Score:3, Informative)
Re:People will always try (Score:4, Informative)
Actually the Carnot cycle puts a limit on the conversion of heat energy into any other form of energy (kinetic, potential, electrical, magnetic, chemical, nuclear, etc). However, heat is the only form of energy so limited. Other conversions, say chemical => electrical are only limited by the second law of thermodynamics. For that matter, converting any other energy to heat can be very efficient. Electrical energy => heat, for example.
So, something like a microturbine [energy.gov] is limited to ~30% efficiency for electricity generation. Larger plants can get up to 35% efficiency. A fuel cell has no such limit and could potentially reach into the 90% range for efficiency of electricity generation. Hybrid fuel cell-turbine generation systems [doe.gov] are being tested which have efficiencies of over 50% and they speculate that they could hit 70% or more. The problem with such a system is that the upfront cost is very high and it does not get offset by the savings in fuel. Not yet, anyway.
Remember too that conversion of any energy to heat can be very efficient. Natural gas furnaces can be extremely efficient, as high as 97% [energy.gov]. That's because converting chemical energy => heat is not a Carnot limited process, and is only limited by the second law of thermodynamics.
Re:Perpetual Motion Machines of the First Kind (Score:3, Informative)
If this could work, we could have cars and airplanes that ran off the heat of the air surrounding them.
Nobody ever spoke much of harnessing the power of the heat in the ocean, until those thermal gradients were discovered between surface waters and deep water. With two heat reservoirs you can transfer heat from one to the other, extracting some of the energy as a tax as it moves from warm to cold regions, generating nice things like fresh water and electricity. [slashdot.org]
With no temperature differential, there is no way to do this without causing a global decrease in entropy.
Re:Perpetual Motion Machines of the First Kind (Score:2, Informative)
A perpetual motion machine of the first kind is basically a machine that loses almost no energy because it has so little friction, air drag, resistance, etc. Because it loses energy so slowly, it can continue to move for a very long time. But because it's moving doesn't mean you can continously extract energy from it, as any attempt to extract energy will slow it down and eventually stop it. You will never get more energy out than is already "stored" in the machine.
An example is something like a flywheel. Get it spinning, and because a well built flywheel has almost no friction, it will spin for a very long time. But try to extract any energy from it and it will quickly slow down and stop. Same with a simple pendulum.
PM and patents (Score:2, Informative)
Regarding perpetual motion, however, the US has a strict patent policy. According to federal statute, 35 USC 101, perpetual motion machines are explicitly unpatentable as inoperative.
Re:A serious question (Score:3, Informative)
What proof of perpetual motion would physicists accept? The answer to that question is this: none.
Not true. You build a machine that operates forever, and it works, and it can be reproduced...well, then, you would've rewritten physics. Rewriting physics, you see, happens every once in awhile. Newton, Gauss, Einstein -- someone comes along and provides a better way things work. And, here's the thing: if they can show that they're right, they'll be accepted. The reason perpetual motion inventors are ridiculed isn't that physicists have some secret cabal out to discredit them, it's that none of them have ever worked.
Should anyone ever succeed, I don't think paying back the mocking will be high on their list of priorities -- I would rather go for cashing in the big, fat checks.
I don't know of any other law of physics that everyone accepts to an infinite number of decimal places without question...Instead of mocking inventors - physicists would do well to spend their time trying to find out if there are any bugs in the algorithms nature uses to calculate energy.
The universe is not an Intel Pentium CPU. It doesn't do floating point arithmetic, and applying ideas like decimal points and algorithms to it is kind of silly.
The laws of physics predict that when a star collapses to a singularity during the formation of a black hole that an infinite amount of energy is released. Is this a problem?
Well, geewillickers! Why hasn't anyone ever seen this before? You must be right! Whole fields of science will be revisited now that you've pointed out...oh, wait. Except a star collapsing to a singularity doesn't release an infinite amount of energy (a singularity has infinite density, not infinite mass). Nevermind.
Re:A serious question (Score:3, Informative)
As to Scientific American: Who the hell cares? If you have a perpetual motion machine, and you can demonstrate it, and it's replicable, then all the naysayers will come around, or be laughed at themselves. Same thing with every other physical 'law' that's been overturned. But...until you get that proof, expect to be laughed at and called a fraud, since you're filling the same shoes as the last ten thousand frauds who thought they had a perpetual motion machine, as well. As humans, we get this thing called "learning from past experience".
As for the formula: that's funny. I was going to use the 'will run their mouths on subjects they know nothing about' to describe you.
First: It's pretty obvious that a star compressing into a black hole does not release an infinite amount of energy:
1) Stars compressing to a black hole release some percentage of energy as heat.
2) Any non-zero percentage of an infinite amount is an infinite amount.
3) Stars have collapsed into black holes already.
4) An infinite amount of heat subsequently failed to wash through the universe.
The amount of energy released by stars collapsing into black holes has been theoretically examined, and while large, is certainly not infinite.
Second: You can't say anything about what happens within the event horizon for sure, so trying to use any formula on anything going on within it is pointless, whereas (gasp, shock) if you use the event horizon for the radius, the numbers actually seem to make sense.