TL;DR The energy is not being created freely, so why shouldn't it work?

We have all seen the YouTube "perpetual motion" machines. You know, the computer fans with magnets taped on them and hidden 9 volts in the center. However, after following these scams for years and even designing a few myself, it got me thinking. Can we make an energy-producing magnet wheel without providing energy ourselves?

Magnets have domains in them where their electrons are spinning in the same way so the magnetic field is not canceled, resulting in a net magnetic field.

According to thermodynamics, these electrons are naturally moving back to a random direction. Magnets do not last forever. Therefore, could we use the strong power of magnetism to generate electricity much like a generator? Can we make a wheel spin with magnets?

Here is what makes this NOT a perpetual motion machine. Although some types of magnets can be found naturally, materials are required energy to become magnetic. Entropy wants disorder and the air around the magnets jiggle the domains of electrons back to random directions. The domain directions are nonspontaneous while identical; energy must be provided to create these magnets.

I like to imagine magnets as some sort of magnetic batteries. Let's take the NdFeB. Once powered, according to neodymiumearthmagnets, the magnet will last 10 years. The domains are repositioning during this time until as neutral as before.

All of this was basically to get the idea into your head that these machines are not truly perpetual motion. This could mean that it makes sense for magnets to beat the other forces and spin. The energy is coming from somewhere.

What do you think? Are there strong enough magnets to beat the forces? If so, would it be efficient enough? More importantly, is any of this wrong? What can I take from this?

TL;DR The energy is not being created freely, so why shouldn't it work?

  • $\begingroup$ It actually releases energy to magnetize a ferromagnet (though probably less, than is lost to defects in the process). The loss of magnetization of a magnet is due to fluctuations, driving the system to the higher entropy state (as the free energy is minimized not the energy and we do not live at $T = 0$). $\endgroup$ – Sebastian Riese Jun 6 '15 at 22:46

The problem is not that the magnets disorganize with time, you could have permanent perpetual magnets and the argument will be the same. The system, using magnets or anything else, will reach a equilibrium position. It is difficult to discuss the reason without a specific example, but there is no energy coming from the "dissolution" of the magnets, there could be a low friction system that takes a lot of time to stop, but as soon as you try to use the kinetic energy it will slow down and at most you will recover the initial energy you spent to create the initial configuration. The system will eventually halt into an equilibrium position. NOTE: if you can make a magnetic battery is a completely different question, but it is not supposed to play a role in these pretending perpetum mobile devices.

  • $\begingroup$ Thank you! Yes, I realized that energy wouldn't be released from the dissolution, but I probably forgot to erase some parts where I said that. Also, the battery part was just something I used as a similarity since you put energy into it and then it loses that energy over time. Of course, the difference is that it will drain despite use. $\endgroup$ – Dylan Spano Jun 6 '15 at 23:00

If I get your main question, it is 'is it possible to create an energy - producing machine? : you ask "Can we make an energy-producing magnet wheel without providing energy ourselves?"

The answer is no. The reason is that energy cannot be created or destroyed, only converted from one form to another. See Energy.

If you are asking if you can use magnets to perform the equivalent function of a machine doing work ( notice I do not say that magnets perform work, this is debatable), then the answer is yes. For example you could use a machine to pick up a metal objects lying on a shop floor, or you could use a permanent magnet. Of course the magnet will have to be placed a few milimetres above the object, but even a purely mechanical device would be doing work if moving the object against gravity throught the same distance.

I encourage you to do your own experiments and work out the physics of magnets, energy and work.

As for perpetual motion, just remember that the Earth is said to be orbiting the sun for 4.5 billion years.


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