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EDIT: I'm talking about generating electricity perpetually using only the magnets with no additional energy input.

I'm sure the answer is no, but can you explain why it's not possible? Does it violate the law of conservation of energy? It seems like magnets not only can apply a force but can also do work, so I don't understand why they wouldn't be able to generate electricity.

Actually, permanent magnets can generate electricity briefly if they are close enough to attract each other and collide, it can create a spark, if the magnets are strong enough.

But I'm talking about generating electricity perpetually.

Qmechanic
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A permanent magnet has an associated magnetic field (obviously). What is not as obvious is that the magnetic field has an energy density which is proportional to $B^2$.

When two magnets are aligned such that their magnetic fields are in the opposite direction then the energy in the field is reduced. This leads to a force (opposites attract) which can do work. The amount of work done is equal to the reduction in the field energy.

Regardless of how complicated your arrangement of magnets, the field energy is initially finite and cannot be less than zero. So there is a finite total amount of energy that can be extracted with even the most clever arrangement. Once the magnet configuration reaches its minimum-energy configuration, the system cannot move away from that configuration without energy input from somewhere else. The forces (the gradient of the field energy) all point towards the minimum.

This is similar to your collision-with-a-spark idea. Once the magnets reach that low energy configuration, to extract any more energy requires energy input to move away from the minimum and go back to a high-energy configuration.

Dale
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Among other things it violates conservation of energy. Generating a current requires you to push the electrons in the part of the wire that's near to you into their neighboring electrons, which then must push into their neighbors, all the way down the line. Obviously the electrons at each stage resist this due to repelling charges, so you need to do work to move them. That work requires energy to come from somewhere. It cannot come from stationary, permanent magnets. There's no kinetic energy in that scenario to take by assumption of being stationary, and the only other potential source of energy - the magnetic field - isn't changing in this case either.

Brick
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  • See my reply to Bob D. – 228 Jul 26 '21 at 21:51
  • This is the reason. Or at least one of them. I don't understand your question / comment to Bob D or what more you think you'll get. You cannot do it because it violates conservation of energy. @228 – Brick Jul 26 '21 at 22:47
  • I know it cannot come from stationary magnets. That doesn't answer my permanent magnets cannot cause a rotor to spin if you arrange them in a certain way. – 228 Jul 26 '21 at 23:09
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    I cannot understand what you’re saying. Maybe you’re using the wrong words? I cannot guess what you mean though. – Brick Jul 26 '21 at 23:58
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The magnetic field caused by a magnet, like an electric field caused by charge and a gravitational field caused by mass, can only store energy. They can't create energy.

The magnetic field can convert mechanical energy to electrical energy, but it requires a mechanical energy input. An example is moving a magnet through a coil of wire, or moving a coil of wire over a magnet, the relative motion of which induces a voltage across the ends of the coil. But a mechanical energy input is needed to cause the motion of the magnet or the coil.

Hope this helps.

Bob D
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  • Right, but why is it impossible to use magnets in order to create mechanical energy, such as turning a rotor, in order to convert that to electricity? You would have to find some sort of configuration that could possibly make that happen, but what would you say makes it impossible? – 228 Jul 26 '21 at 21:50
  • You must provide mechanic energy to the rotor in order to generate electricity. – Jun Seo-He Jul 26 '21 at 22:29
  • Read this:https://en.wikipedia.org/wiki/Maxwell%27s_equations – Jun Seo-He Jul 26 '21 at 22:30
  • @JunSeo-He I think the OP is thinking about something along the lines of the following: Take one bar magnet on a shaft to allow it to rotate. Bring another bar magnet close to it so that it attracts the magnet on the shaft and starts it spinning. – Bob D Jul 26 '21 at 23:02
  • @BobD Yes. Why can't you use permanent magnets to create rotation which then could be used to generate electricity. I mean, you would have to figure out a way to arrange the magnets so that they could cause rotation, but it doesn't seem like it's something that should necessarily be impossible, meaning, it would violate the laws of physics somehow. – 228 Jul 27 '21 at 01:10
  • @228 The problem is movable magnet will stop rotating when the opposite poles face each other. To continue the process you would have to apply a torque to the movable magnetic to return it to its original position, i.e., you would have to do work. The overall result is zero net work done. The gravitational analogy is gravity does work to give a falling object kinetic energy. But an external agent has to do an equal amount of work to return the object to its original height to that the process can be repeated. End result: zero net work done. – Bob D Jul 27 '21 at 14:01
  • This illustrates the point the field (electric, gravitational and magnetic) can store an convert energy but never create it. – Bob D Jul 27 '21 at 14:02
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You can for a short time, but not permanently.

Energy is conserved. It can change from one form to another, but you can't create it or destroy it. Potential energy is is one form of energy. Kinetic energy is another. An electric current is moving electrons. It also contains a form of energy.

Suppose you have two magnets separate by a short distance. One is glued down and the other is free to move. They attract. Magnetic forces propel the free magnet to the fixed magnetic. It gains speed and kinetic energy.

Now repeat the experiment, but add a loop of wire. The free magnet passes through the loop on the way to the fixed magnet. The wire loop experiences a changing magnetic field as the magnet passes by. Changing magnetic fields exert forces on charges. Wires have electrons that can freely move within the wire. Moving electrons is a current. So this time the moving magnet generates a current.

But this only lasts for a moment. The free magnet hits the stationary magnet. The collision bumps atoms in both, causing them to vibrate a little harder. Kinetic energy has been changed to heat.

The moving electrons aren't totally free to move. They bump into atoms of the wire, causing them to vibrate a little harder. Electric energy turns to heat.

mmesser314
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A voltage can be induced in a conductive loop only if the magnetic flux through the loop changes. This can be done by a) a moving magnet or b) if you move the conductive loop which can't be done without some input energy.

Jun Seo-He
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Can the repulsion effect of magnets be used instead? Fix one magnet to the left (L Mag) with - charge facing right. The magnet on right (R Mag) has - facing left. The magnet on right now is connected to a 'piston' and is pushed away from L Mag, and a mechanism is in place to return R Mag to close to L Mag. This would work if enough energy is created from the repulsion to A. return R Mag to a position with potential energy AND B. have surplus energy to do work. The whole system would require very little resistance to minimize lost energy.

bacid
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Maybe the creator (God) could show us how to do it seeing how all this was created by "him" all jokes aside I do believe his opinion it makes sense that everything was created so why can't energy be created also quantum mechanics illustrates that the observer collapses the wave function so maybe it's are prospection of what things can and can't be done are holding us back? Just food for though a opinion a rant but there could be truth would love to hear any response

Robert Kiel
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When you add a (theoretical) 100% SHUNT material thin enough between two magnets in a series, you can split the magnetic field in half and redirect it so that the other magnets can push beyond the shunted one. The magnet mortor can spin until the magnets are completely depleted if the right gears are used. But the shunt laterial density isn't high enough. Although mu metal accomplishes this, it still leaves behind some friction, which slows down the device. David Adair told me that pure metal produced in space may completely repel magnets. Perhaps this is how the new TicTac UFOS/UAPs work. Perhaps the International Space Station has developed extremely pure metals that are thin enough to SHUNT a field while yet providing sufficient bLACK space to achieve zero-drag and power a motor. The work is done by alternating opposing fields in the gap between the two magnet rotors. The shunt functions like the fan blades of a movie projector, opening and closing to provide the illusion that there is no opposing magnetic field. This is illustrated in a patent with a straightforward gear mechanism.

Ross Marshall
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12.01.23 think outside the box.

  1. the "law of conservation of energy" is a lie. why? well look around you. obviously the universe which - is made of matter and every was created. so energy can be created. we just don't know how to do it.
  2. maybe magnets and electricity aren't the way to do it. maybe there is a different way - antigravity? who knows?
  3. if this sounds far fetched - maybe it is - but so was "the earth is flat and the sun is the center of the universe"
  4. Good day to you sir!
J. Rand
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