In sci.physics.relativity, PCB

wrote
on Sun, 11 May 2008 10:59:23 -0700 (PDT)
:
On May 11, 7:04 pm, The Ghost In The Machine
wrote:
In sci.physics.relativity, PCB

wrote
on Sun, 11 May 2008 07:48:59 -0700 (PDT)
:



PCB wrote:
I read somewhere that only electric currents generate magnetic fields.

Where is the electric current in a permanent magnet?

Is a permanent magnet a frozen electric current in matter?

It seems that the electric current in a magnet would like to flow, but
it cant.

Discus

This is not an obvious relavistic concern;
followups therefore to sci.physics.

Briefly, however, the permanent magnet *is* a manifestation
of an electric current, though it's hard to specify

Thanks, this is what I said, and Tom said I was wrong.

I'd have to look back through the thread to see what Tom
(and, for that matter, *which* Tom) said.


precisely since I'm not up on my quantum mechanics.
The Bohr model is very discredited by now, but the general
idea is that of a charge orbiting another charge; the
orbiting charge is a current.

Thanks again, so is a frozen currrent indeed.

Not frozen at all. It's moving. Granted, in QM one
doesn't see the movement, but instead a probability
distribution of states.



Of course in QM things are expressed a little bit
differently, but I've forgotten the details.

Once we've established that an atom has a pair of poles,

Cant see how a single atom can have poles

Easy. The electric current around the atom generates a
magnetic field, much like a one-loop solenoid (or in the
case of the iron atom, 26 electrons trying to compete with
one another).



it becomes simple, since iron in particular is a series
of magnetic domains, which are crystalline structures
("grains") in the metal; a magnet has more of them lined
up in a preferential direction than not.

A grain yes, you can align them, but not a single atom as Tom said.

You cant align individually atoms, or I cant see how

Crystals align the atoms within them. These are the "grains".
The size thereof depends on how one manufactures the item.



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Thanks

Seems that you know more about this concern than anybody else here and
there, so this must be the proper group.


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