Re: will a magnet stick on the ground of North or south pole?

The Earth's magnetic field behaves as a dipole (in fact, more than
90% of the field can be explained by a dipolar field) in all the
regions, not only at the poles. That's why we can use a compass to
obtain the north direction (if we consider the magnetic declination
of the point where we are measuring, of course).

But the Earth's field is not so strong that you could see a bar
magnet stick on the ground! If you get a magnetized needle, you can
notice that near the magnetic poles (that don't coincide with the
geographic poles) the needle remains in the vertical position, and
in the magnetic equator (that is not the geographic equator as well),
the needle will stand on the horizontal. In the other places, the
needle will dip a certain angle, that we call magnetic inclination,
that varies from place to place in the Earth.

Among other things, the Earth's magnetic field makes a barrier
against the particles provenient from Sun in all regions, except
at the magnetic poles, where the particles can enter, originating
the auroras.

Best regards

Eder C. Molina
eder@iag.usp.br
Dept. of Geophysics
IAG-USP