ELDER! (Or someone) Please explain this
- Thread starter Big Don
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cdunn
2nd Black Belt
That block is a magnet. When you move a magnet next to a conductor, the movement of the magnetic field pushes on the electrons in the conductor, and accelerates them off, forming a current. Everything obeys Newton's laws, so the electrons also push back on the magnet.
Like the MagLev trains? Or different?
cdunn
2nd Black Belt
Very distantly related. Maglev is a much more active proposition.
Also, this won't happen if your conductor metal is significantly ferromagnetic (Iron, most steel, etc) - The domains in the conductor will line up and say hi with a much higher level of force than the current.
Steve
Mostly Harmless
Neato.
Of course, nobody really knows how magnets work, anyway. I mean, yes, we know they they push or pull. We still don't know why.
Don't make me come in there and explain MVAr's ... I warn you, it'll make you cry ... either that or believe in voodoo :lol:
Are you sure on that, Bill? Isn't that what Maxwell's theory on electromagnetism was about? http://www.astrohandbook.com/ch12/EMFT_Book.pdf
Ohttp://www.astrohandbook.com/ch12/EMFT_Book.pdfr do you mean in a "why is water wet?" kind of way?
Every description of magnetism begins from the assumption that there is a 'force' that exists, and then attempts to explain why it works. None of them explain what that force is, except by being self-referential. The force is an electromagnetic field. What's a field? A force. What's a force? A field. Yeah.
I understand the idea that the magnetic force is a field, that it has poles, yada yada yada. I did the experiments in grade school with a magnet and a piece of paper and iron filings to see how they arranged themselves along the magnetic field of a magnet held under the paper. Got it. Now, what is that field? Right. We can explain the effect; not the cause.
Magnets exhibit motive force. Lots of things exhibit motive force; even lasers have a 'kick' to them, although miniscule. Solar energy exhibits motive force. Wind exhibits motive force. But all of these things are 'things'. Some'thing' pushes; energy is affecting mass. Magnetic 'waves' or 'fields' are massless and energyless, yet they have motive force. Uh huh. The last I heard, there was a theory that photons are being exchanged, which creates the four fundamental forces. Other than that, dunno. Does that seem likely to you?
We also have no idea why some materials are ferrous and magnetic and others are ferrous and not magnetic. Or why some alloys of ferromagnetic materials ARE good magnets, even better than iron, and some are poor magnets or non magnetic entirely. We find out about new magnetic allows by trial and error, we can't seem to predict which allows will be most magnetic. Because we don't know how magnetism works.
ICP is quite correct when they ask the question.
Magic.
Magnets are easy. They're like people. Some things like each other, some things don't. If they like each other -- they try to hug. If they don't, they push each other away.
oftheherd1
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That ringing sound you hear is the Nobel committee calling about your prize in theoretical physics.
Empty Hands
Senior Master
I don't pretend to understand it, but this article on Wikipedia explains the quantum-mechanic origin of the magnetic field and why some materials make good magnets and others do not. The model that led to it was apparently developed in 1927.
Contra ICP, scientists ain't lyin' and gettin' me pissed.
Yeah, no. Even that theory only shows that some materials it predicts should be ferromagnetic are and some it predicts should not be ferromagnetic are not. But some are not in compliance with this theory.
Check this out, this is an application of Lenz' Law that creates what's called the Meissner Effect. The black material is a superconductor, when it is cooled with whatever that cryogenic liquid is, the eddy currents are strong enough for the magnet to levitate above the superconductor.
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