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Re: [Phys-l] Movie Physics Gafs



Actually the poles of the compass are named after the direction that they
align to. And this is also true of a bar magnet. Then consulting the
Wikipedia the magnetic poles of the Earth are called "magnet North", and
"magnetic South", but of course the magnetic North is actually the S pole of
the Earth's internal magnet. But if we wait awhile, it may be reversed.
But I don't think I have the time to wait for this.

When you hang a bar magnet on a string students are often surprised to see
that it points to the North compass direction.

As to whether "North seeking" is bad terminology, it is what might be termed
an idiomatic expression meaning that the N end of the needle points in the
directin of N. Idiomatic expressions are not wrong, but they can be
misleading to those who do not understand them. If such a simple expression
is deemed wrong, then "heat flow" is even worse. I would say the wrong is
the wrong word to use for the expression. Or is this too boringly pedantic?

John M. Clement
Houston, TX




Magnetic poles are named after the compass, not after the big magnet
inside the earth. The physics dictates you can't have it both ways,
so you have to choose. Again: Complexifying the terminology will
not change this fact.