EARTH'S MAGNETIC FIELD
· A powerful magnetic field surrounds the earth, as if the planet had an enormous bar magnet embedded in its interior.
· However, geophysicists believe that convection currents of charged, molten metal circulating in the earth’s core are the source of the magnetic field.
· A compass needle is a true bar magnet; one end of it is called “north-seeking” because it is attracted to the magnetic pole that lies within the earth in the northern hemisphere. The other end of the compass needle is a magnetic pole of the opposite kind, and is therefore attracted to the earth’s other magnetic pole. Since opposite types of magnetic pole attract each other, the pole in the northern hemisphere, although called the north magnetic pole, is itself of the south-seeking type, and vice versa for the opposite hemisphere.
