How Do Magnets Continuously Generate Electricity?

[Irresistible_Force]

Ok, from the big bang, to the Stars, as radiation to the plants, eaten by animals that I just had for supper...no really.

Everything has electrons. Magnets are always surrounded by a field. Use the M field to induce current into a wire, now you have E and M fields. We can use electricity to generate a magnetic field. We can use a magnet to generate electricity. We can even use an elctomagnet to do the same. Something is missing. Where does the original fields draw energy from?

Think about it. I don't want the easy textbook answer. It's always, it's just already there...come on. No it's not.

You can't tell me that if I wake up one morning and start moving a magnet over a wire, it will make electricity indefinitely, with no deterioration of the magnet. That would mean that the magnet has an infinite field stregnth. Not likely.

So really, where does it come from?

 

[Harmony]

Quoted from Wikipedia
"In quantum physics, the photon (from Greek φως, "phōs", meaning light) is the quantum of the electromagnetic field (light). That is to say, electromagnetic fields are made up of large numbers of photons, and the electromagnetic interaction is mediated by the exchange of virtual photons."

 

[zoobyshoe]

When you generate electricity with magnet and wire the energy comes from whatever is moving the magnet, not the magnetic field. The special property of the magnetic field is that it can interact with the electrons in the wire, pushing them, so to speak, in one direction or the other. The energy comes from your hand and arm moving the magnet, or from the engine, whatever kind it may be, that moves the magnet. If the magnet's moved by wind power, or water, then the energy is coming from the wind or water. You aren't harvesting any energy from the magnet or it's field.

 

[JohanL]

Think about it. I don't want the easy textbook answer. It's always, it's just already there...come on. No it's not.

Which textbooks gives that answer?
zoobyshoe gave you the textbook explanation, the correct explanation.

 

[actionintegral]

I don't think the original posters' question has been addressed. I think he confused the issue by mixing in magnetism. Do you think maybe the following was his question?:

"I have an electron in one hand. I pick up another electron and move it towards the first and then let go. That electron will fly away. I do this again. Another electon flies away. I can do this repeatedly for a thousand years, and the original electon never seems to wear out! It seems to be an inexhaustible source of energy..."

 

[pallidin]

To add something: Magnets DO have a "lifespan".
The following qoute is from http://www.magnadrive.com/faq/faq-magnets.shtml and is in respect to neodymium(rare-earth) magnets.

Q: How long will the magnets last?
A: The half-life of the magnets is 2,000 years.

 

[Irresistible_Force]

I don't think the original posters' question has been addressed. I think he confused the issue by mixing in magnetism. Do you think maybe the following was his question?:

"I have an electron in one hand. I pick up another electron and move it towards the first and then let go. That electron will fly away. I do this again. Another electon flies away. I can do this repeatedly for a thousand years, and the original electon never seems to wear out! It seems to be an inexhaustible source of energy..."

This is closer to the answer that I was looking for. Thank you.

Take an atom of hydrogen, the electron spins around it forever as far as we know. Why can it do this? Shouldn't it slow down eventually? Or fly away? Will the proton always pull equally to keep it in place? If so, how? In any other sense of the word, an atom is an engine. It does work. Not really useful most of the time, but... So, it is an engine that is always running. Any system that does work requires energy to be input. Does not this hold true for an atom? If so, then where does it come from? (yes they are held together by electrostatic force...but, where does the force originate?)

I'm sorry to be so naeive, I am just uneducated, but I am trying. Some questions just are not answered anywhere. I was more than a little vague intentionally. I wanted a wider response pool. I thank those that took the time to answer.

 

[Astronuc]

Actually, Zoobyshoe is correct. A moving magnet produces a time varying magnetic field in a conductor which induces charges to move, and moving charges a current make (assuming there is some net motion).

Some mechanical energy (by virtue of force through some displacment) must be expended to move the magnet.

Take an atom of hydrogen, the electron spins around it forever as far as we know. Why can it do this? Shouldn't it slow down eventually? Or fly away? Will the proton always pull equally to keep it in place? If so, how? In any other sense of the word, an atom is an engine. It does work.

In a bound state, with no change in potential energy, the atom does no work, or rather there is no work on the electron. QM explains why the electron does not slow down, or fly away, but the electron 'remains in orbit', unless an external influence acts upon the electron. The external influence could be a photon, another electron, or some charge particle.

 

[MalayInd]

Take an atom of hydrogen, the electron spins around it forever as far as we know. Why can it do this? Shouldn't it slow down eventually? Or fly away? Will the proton always pull equally to keep it in place? If so, how? In any other sense of the word, an atom is an engine. It does work. Not really useful most of the time, but... So, it is an engine that is always running. Any system that does work requires energy to be input. Does not this hold true for an atom? If so, then where does it come from? (yes they are held together by electrostatic force...but, where does the force originate?)

You would have heard of Newton's first law of motion.
If a body is moving, it will keep on moving in its state until a and unless a force on it.
Now, if a body is moving and there is no force on it, it will continue to move forever. What provides the energy?
(I know that it is not answer to your question, it is just an extension)

Keep Smiling
Malay

 

[actionintegral]

For my part, after thinking on it for a while, I just said "an electron is an inexhaustible source of repulsive force" and moved on. It's not a trivial question, I just don't think there is an answer.

 

[DaveC426913]

In our macroscopic world, we take friction and energy loss as a given. We assume that something in motion will eventually stop unless more work is put into it.

This is NOT the general case in the universe. The general case in the universe is that things in motion stay in motion. And on the atomic/subatomic scale, there is no loss due to friction or heat or whatever.

It would help to recognize that, even in our macroscopic world, these losses due to heat or friction or whatever aren't really lost, it's just that the energy is converted (not lost!) into forms that are of no use to us (i.e. not recoverable).

 

[Duncan]

I don't think the original posters' question has been addressed. I think he confused the issue by mixing in magnetism. Do you think maybe the following was his question?:

"I have an electron in one hand. I pick up another electron and move it towards the first and then let go. That electron will fly away. I do this again. Another electon flies away. I can do this repeatedly for a thousand years, and the original electon never seems to wear out! It seems to be an inexhaustible source of energy..."

As to this question, zoobyshoe answer is correct regarding this situation as well. Here the energy is added to the system when you move the electron closer to the other electron. Once you let go of one of them then the potential energy of the electron given to it by moving it closer is released as kinetic energy.
Remember charge is conserved as well as energy. So if the electron was losing its charge then it would be breaking the laws of physics.

 

[Irresistible_Force]

In our macroscopic world, we take friction and energy loss as a given. We assume that something in motion will eventually stop unless more work is put into it.

This is NOT the general case in the universe. The general case in the universe is that things in motion stay in motion. And on the atomic/subatomic scale, there is no loss due to friction or heat or whatever.
It would help to recognize that, even in our macroscopic world, these losses due to heat or friction or whatever aren't really lost, it's just that the energy is converted (not lost!) into forms that are of no use to us (i.e. not recoverable).

Thank you all. This is the best answer that fits the question I was trying to ask, but did not know how.
So the rules are different on the atomic scale. Interesting. It is the losses in the macroscopic world that I was trying to understand -why they don't apply to the atomic scale. The closer I get to the answers the further away the goal gets.
Just as a wild example though, if you put a generator motor into a high state of spin in orbit (vaccum, zero g) and shielded it from radiation, etc. would it spin indefinitely?(fictionally assume friction is eliminated somehow)?

 

[SizarieldoR]

Actually, Zoobyshoe is correct. A moving magnet produces a time varying magnetic field in a conductor which induces charges to move, and moving charges a current make (assuming there is some net motion).

So, if fluctuations in the magnetic field are caused by motion, then can we make gamma radiation if we, for example shake a magnet fast enough?

 

[Quaoar]

Allow me to make an analogy:

Lets say magnetic fields are a broom, the metal is represent by the floor, and electrons are bits of dirt on the floor. You push the broom along the floor, moving the dirt around. The system is composed of four things: You, the floor, the dirt, and the broom. Which is doing the work? Does it make sense to say "the broom has infinite energy, because it can push the dirt around for eternity"?

That's what magnetic fields are. They are the "broom" in these interactions, a way of converting effort from one form to another.

 

[Farsight]

So, where does energy come from?

 

[G01]

So, where does energy come from?

Asking this question is like asking where mass comes from. Energy is a property of the universe, as is mass. All mass and energy originated in the big bang. The energy that exists today originally appeared in the big bang. There has been no energy added to or taken away from the universe since then.

 

[Farsight]

What about symmetry breaking?

 

[eeka chu]

There has been no energy added to or taken away from the universe since then.

Totally wrong actually, you're forgetting the blue screen sink factor.

After an hour two of dealing with the blue screen you'll feel tired and yet have achieved zero gain.

 

[jaredkipe]

There is energy stored in E&M fields.

Energy is a construct. It allows us to predict things, but it isn't like you can hold it and say "ahh so this is what energy is".

 

[rcgldr]

Energy is a property of the universe, as is mass. All mass and energy originated in the big bang. The energy that exists today originally appeared in the big bang. There has been no energy added to or taken away from the universe since then.

How strong is the evidence that no energy / mass is being added / taken away. For example, the universe seems to be expanding at a rate faster than it "should", maybe due to "dark matter". Assuming that it is "dark matter" or something similar, how do we know that the amount of "dark matter" has always been the same?

Do black holes "suck" up energy from the universe?

 

[Farsight]

There's another thread about "Hawking radiation":

https://www.physicsforums.com/showthread.php?t=125554

The idea is that "virtual particle pairs" are created near the event horizon. The negative energy fluctuation falls into the black hole, and the positive energy fluctuation is freed into the Universe. So in this respect black holes would be creating energy.

I have to say I'm not utterly convinced by this myself.

 

[brbeck777]

This is one of many questions that I have pondered over time. Where does energy come from? What produces gravity within mass? Does the universe and time have an end or not? If you divide and atom down to protons, nuetrons and electrons, then divide down to quarks then to string theory then what? Something is always there to create energy for the next level. One can divide till the end of time and not be satisfied. It is fun to search for the answers and I hope we never stop, BUT I believe we are not meant to know all and that we may never understand everything. The more I learn the more I realize how small we are and that I am a fool to suggest that there is absolutly no all powerful creator. One thing I am sure of is that I am not the creator.

 

[Farsight]

I thought energy could be neither created nor destroyed.

 

[brbeck777]

That means that we can't do it not God. I appreciate your sense of humor. Thanks.

 

[brbeck777]

You are correct jarekipe in saying that we use it to predict.

 

[brbeck777]

Does anybody have a theory on what existed before the big bang and what caused the big bang? There must have pre-existed energy to create that kind of a bang!

 

[Canute]

Yes they do. Try mathematician George Spencer Brown's Laws of Form(1969). I'm not sure it would be right to say that he himself agrees with BB theory, but his theory of cosmogenesis is consistent with it. It is fundamentally based on the idea of symmetry-breaking, but is a psychophysical theory rather than a strictly physical one. There are others.

 

[Farsight]

Perhaps Before the Big Bang is the wrong way to think about it, because that's like saying North of the North Pole. And there's some very fundamental underlying concepts here such as What Is Time? and What Is Energy? I could give you my views, but they aren't physics, and this is a Physics Forum. So you'll have to wait for somebody who can give you an authoritative answer. Meanwhile you could search Google on "Before the Big Bang".

 

[rkkane]

There's another thread about "Hawking radiation":

https://www.physicsforums.com/showthread.php?t=125554

The idea is that "virtual particle pairs" are created near the event horizon. The negative energy fluctuation falls into the black hole, and the positive energy fluctuation is freed into the Universe. So in this respect black holes would be creating energy.

I have to say I'm not utterly convinced by this myself.

from what i understand of this the black hole is not creating energy it is substituting some of it's mass for energy. just like a nuclear reaction does.

 

[Farsight]

Good point.

Edit: I wish I'd thought of that.

 

[BoTemp]

Ok, from the big bang, to the Stars, as radiation to the plants, eaten by animals that I just had for supper...no really.

So really, where does it come from?

From the big bang. The energy of the universe is the sum of the kinetic energy of each particle, and the potential energy interactions. Mass is equivalent to energy via E = mc^2, so throw that in too. There is the same amount now as there was 1 sec following the big bang. Why/How all this energy was created is not known. It should be noted that net energy is what's conserved, so a particle and it's antiparticle both created out of nothing doesn't violate any conservation laws. That's the basis of Hawking radiation (black holes radiating energy). My personal theory, which is not backed up by observations at all, as that there is another universe which consists of what we'd call anti-particles. The fact that there is much more matter than anti-matter in the observable universe hasn't been explained.

Energy/mass which falls into a black hole isn't lost. It's in the black hole, and will eventually be radiated out. There are entropy issues involved in black holes (information loss) which haven't been resolved, but not energy.

There's a book out now called "The Final Theory" by Mark McCutcheon. Don't read it, except to test your physics muscle in pointing out his errors. Terrible book, everything in it is wrong. He brought up a similar point to the magnetic field argument, involving gravity: How can the moon be held in orbit indefinitely, having a seemingly inexhaustible gravitational force act upon it, meaning the Earth has infinite energy?

The answer, which is always the case for orbits, is that the force is perpendicular to the change in velocity. The speed of the moon doesn't change in its orbit, hence its kinetic energy stays the same. It's (roughly) the same distance from Earth, so V = -GM/r is constant. The velocity of the moon is changing though, since velocity is a vector quantity, even though its magnitude stays constant its direction changes. Because of this acceleration the moon radiates energy away. In this case, the energy radiated is extremely small, and is almost unnoticeable. Qualitatively, the same thing would happen in an atom, if QM weren't true.

 

[Visaliasteve]

This is a question I find fascinating and have no answer. I have read the answers but I believe there is more to a magnet than meets the eye. I believe there is another force at work that we have not discovered. I am not referring to magnetism itself as I belief a magnet may simply act as a lens for another energy source that we know little about such as gravity. Notice the mathematical formulas for gravity and magnetism are similar. Some of the answers refer to work and state that a magnet does not perform work therefore does not expend or require energy; I say it does work when it is stuck to another object as it defies gravity without any external energy source. In fact magnets can support holding weights many times their own mass. I have no answer for this but who ever unlocks this mystery will be worth a fortune.

 

[diazona]

This is a question I find fascinating and have no answer. I have read the answers but I believe there is more to a magnet than meets the eye. I believe there is another force at work that we have not discovered. I am not referring to magnetism itself as I belief a magnet may simply act as a lens for another energy source that we know little about such as gravity. Notice the mathematical formulas for gravity and magnetism are similar. Some of the answers refer to work and state that a magnet does not perform work therefore does not expend or require energy; I say it does work when it is stuck to another object as it defies gravity without any external energy source. In fact magnets can support holding weights many times their own mass. I have no answer for this but who ever unlocks this mystery will be worth a fortune.

umm... "defying gravity" to you evidently just means not falling down. It doesn't take any energy not to fall down.

There's nothing special about a magnet holding up something many times its own mass. In fact the mass of the magnet itself has nothing to do with how much it can hold; only the strength of the magnet does. The magnet itself is just like a chain link between the thing being held up, and the thing holding the magnet up. Surely you can imagine a very lightweight yet very strong link in a chain...

And there's really no mystery about magnetism. If you want to think it's mysterious, then I suppose that's your right, but physics has a perfectly good explanation for why magnets work the way they do. (Of course, there is the open question of "unifying" gravity and everything else - you're not the only one who's noticed the similarity between the equations of gravity and magnetism. But that's just about making the theories look nice; it doesn't change the fact that they work.)

 

[junglebeast]

This is a question I find fascinating and have no answer. I have read the answers but I believe there is more to a magnet than meets the eye. I believe there is another force at work that we have not discovered. I am not referring to magnetism itself as I belief a magnet may simply act as a lens for another energy source that we know little about such as gravity.

Many of the fundamental forces that initially seem separate have been shown to be manifestations of the same force. For example, the electric force and the magnetic force have been discovered to be caused by the same thing. That's why we now refer to it as one force, the electromagnetic force. If I recall correctly, you can actually derive the magnetic force from the electric force + special relativity...but I could be wrong about that. Since then they discovered that the weak nuclear force is also caused by the same thing as the electromagnetic force, so all three together are called the electroweak force. It seems that the strong force and gravity are not part of the same force. However, according to the standard model all forces are mediated by gauge bosons which is why their formulas may look similar. The difference is that they use different kinds of bosons.

Some of the answers refer to work and state that a magnet does not perform work therefore does not expend or require energy; I say it does work when it is stuck to another object as it defies gravity without any external energy source.

Actually permanent magnets can do work and then do have stored energy. A permanent magnet can be demagnetized from the magnetic load put on it. Have a look at the demagnetization curve: http://femm.foster-miller.net/wiki/PMEnergy

 

[zoobyshoe]

Notice the mathematical formulas for gravity and magnetism are similar.

What formulas?

 

[workmad3]

According to our current knowledge of physics, energy can never be created or destroyed, merely changed in form. So mass can be converted to energy, if you move an object in a positive direction in a gravitational field will transfer energy from yourself to the energy, where it is stored as gravitational potential energy. If the object is then allowed to fall, this will be converted by the gravitational field into kinetic energy, etc etc.

Moving a charged object or magnetic object in an electromagnetic field is the same principle. You need to use your own energy to move the object in the field and this has a corresponding effect of inducing a current (which will be in the opposite direction to your movement in order to resist said movement). Your energy will come from chemical reactions from plants and animal products that you have ingested, these will have gotten energy from the fusion reaction of the sun and the sun got it's energy from hydrogen atoms, and so on back to the big bang.

As for destroying energy... this definitely doesn't happen, but it can be 'effectively' destroyed through heat loss, as this is a loss of energy into heat dissipation that is essentially unusable by anything. This is, AFAIK, the way entropy increases in thermodynamics.

And a black hole can evaporate from hawking radiation. I think our current standard theories on the matter reckon it would take longer for a black hole to evaporate like this than there is predicted time left in the universe. Otherwise a black hole could conceivably become an entropy reducing mechanism in the universe, with energy being 'wiped clean' by the process of being sucked into the black hole and released again as hawking radiation. This is acceptable on a local scale (entropy and thermodynamics is after all statistical. Local fluctuations in the opposite direction to entropy are possible) but not on a massive scale such as an entire black hole disappearing into negative entropy.

 

[zoobyshoe]

Actually permanent magnets can do work and then do have stored energy.

There is no stored energy in a permanent magnet. Poorer quality magnetic materials become demagnetized with use because the magnetic domains don't hold the magnetized positions under stress as well as the newer magnetic materials do. Given the same initial magnetization, old fashioned hardened steel will lose it's magnetism relatively quickly with use, but the average ferro-ceramic magnet, as in an audio speaker, a newer, better material, will stay magnetized indefinitely despite constant use. In the case of the former no energy is being expended by the magnet with each use, rather, the orientation of the magnetic fields of its "domains" are all going out of alignment. In the latter, better, material the orientation is not subject to slippage like this.

Again: a magnet is not using up some fraction of the energy used to magnetize it when it interacts with something else. The process of magnetization is simply to align the magnetic fields of the tiny "domains". How fast they go out of alignment has nothing to do with the strength of the magnetic field that aligned them, it has to do with the material used.

We can use a magnetic field to store energy, but only in the sense we can use a spring to store energy. A magnetic field is not an energy source any more than a spring is an energy source.

If I tie a string to a magnet and hang it from a tree then stick a piece of steel to the magnet the magnet is doing no more work holding the steel up than the tree is doing holding the magnet up. The force in play here ("working against gravity") is just the resistance of molecules and molecular bonds to deformation. As diazona said, the magnet is no different than a piece of chain link here.

 

[Dadface]

To express things really crudely we can say that if it moves or if it can make things move it is energy.Matter is the stuff and energy the thing that can move the stuff.We can define energy and we can discover conservation laws and come up with theories and all the rest of it but these things are just summaries and descriptions of what we are able to observe.Observations,which are severely limited, are key to what is done in physics and with a small amount of confidence we might be able to state ,for example that mass/energy is conserved justifying this on the basis that with the limited observations made so far this always seems to be the case.
Why is it conserved and where does mass/energy come from are really big questions but I am fairly confident with my answer;
I haven't got a clue.

 

[cragar]

nuclear explosions ,