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Magnetic Energy And Force

by CraftyDad
Tags: magnets
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Mar26-14, 07:29 AM
P: 5
Hi, I would appreciate some help here as its been some 25 years since leaving school and I am now expected as part of my duties and training for a youth leader in a cub scout pack to provice some activities in relation to Beaver Cubs and activity badges.

Subject... Magnets.

Now I appreciate that this question may have been asked and please don't shoot me down in flames, the old brain cells have had an addling of 20 odd years and the medication I am on doesn't help with memory.

Magentic force / energy, how is the energy derived in a magnet?

I have watched a youtube posting by the "how its made" TV show on how magnets are made, it however does not answer the burning question of where the energy comes from...

Ignoring any input energy from the user, if two opposing fields come together to repel and likewise come together to attract, where does this magnetic force get its energy from or whatever you want to call it to pull each other together or push away.

I have some practical demonstrations to show things like magnetic line of force / energy and made a rudimentary electro magnet and demonstrations of temporary magnets, Lenz's Law with the magnet going down a copper pipe which is pretty cool.

My worry is that one or more of the Beaver cubs will ask me the question of where do magnets get their energy from and my two options are to suggest we research this further or have the actual answer and I prefer the answer route, keep those hungry minds fed and fattened up :)

So your help is appreciated, anything that you can help me with, you don't really want to see me begging on my knees do you?

Please, keep your answers in terms that I can understand, I read one post and my head imploded.
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Mar26-14, 07:56 AM
P: 22,281
Welcome to PF!

The key here is to recognize that force isn't energy, so maintaining a static force requires no energy input. If it did, you could heat up a book just by letting it sit on a table.
Mar26-14, 09:24 AM
P: 17
Keep it simple I think...

The phenomenon that is Magnetism represents itself through the idea of a Magnetic field. This field is generated in permanent magnets like iron by the permanent magnetic dipoles within the material and in other materials by passing an electric current through them.

Magnetism will therefore be observed when electrically charged particles are in motion within a material. Due to Einstein's Special Relativity though Magnetism and Electricity go hand in hand.

Mar26-14, 09:51 AM
P: 5
Magnetic Energy And Force

Forgetting what I call niggley details like force / energy in a magnet...

When you put to magnets together that repel each other, the force or resistance of them from being pushed together, apart from the obvious like poles repel, what is it as a property in the magnet that does that?

I understand that atoms / particles or whatever are dis-organised when an item is not magnetic.

What is it that causes magnetisim when atoms / particles are lined up?
Mar26-14, 10:09 AM
Sci Advisor
P: 3,648
Quote Quote by CraftyDad View Post

What is it that causes magnetism when atoms / particles are lined up?
Each individual atom is a tiny magnet. When they're arranged at random they generally cancel each other out on average. If you can get them to all line up in the same direction (and stay that way! iron is particularly good about that) they add instead of canceling each other.
Mar26-14, 10:53 AM
P: 5
Ok, so now my greatest fear is this question, why are atoms magnetic.

I can picture an electron buzzing around an atom, I take it that the movement of an electron around the atom this is what causes them to be magnetic, yes?
Mar26-14, 11:38 AM
P: 17,206
Yes, paramagnetism and ferromagnetism both come from unpaired electrons. Here is a good brief overview:

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