The north pole of a compass needle is attracted toward the north pole of the earth. Apparently the earth itself is a large magnet, as shown in FIGURE 29.1. The reasons for the earth’s magnetism are complex, but geophysicists think that the earth’s magnetic poles arise from currents in its molten iron core. Two interesting facts about the earth’s magnetic field are (1) that the magnetic poles are offset slightly from the geographic poles of the earth’s rotation axis, and (2) that the geomagnetic north pole is actually a south magnetic pole! You should be able to use what you have learned thus far to convince yourself that this is the case.

FIGURE 29.1 The earth is a large magnet.