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| Magnetic Force and Magnetic Fields
36
MAGNETIC
FIELD
The lines depicted here are
just a model. But you can
picture a magnet as
producing a countless
number of lines arranged
tightly together. This
invisible force of a magnet
is known as its magnetic
field.
We can neither see nor feel
a magnetic field, but iron
and other magnets will
react to it by being
attracted, repelled, or
rotated.
The field is especially
strong close to the poles,
but as you move away from
the magnet it quickly gets
weaker.
Earth's axis of rotation
Geographic south pole
Earth's axis of rotation
WHICH POLE IS NORTH? C
picture Earth's magnetic field. Compass needles orient
themselves relative to the magnetic lines of force and
thus point in a north-south direction. And in the
drawing above, the artists didn't make an error in
putting the magnetic south pole next to the geographic
north pole! The compass needle, remember, is a little
magnet. The end pointing to Earth's north pole has
long been called the north magnetic pole. That applies
to all magnets — even your bar magnet will rotate such
that the N side is turned toward the north. But since, as
you know, north and south poles always attract each
other, the magnetic pole near the geographic north
pole is logically a magnetic south pole.
CHECK IT OUT
Geographic north pole
This is how you can
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