A permanent magnet is made of a ferromagnetic material, which means that the magnetic properties derive from the spin angular momentum of electrons within that material. In a magnet, the magnetic domains in its substance are aligned.
The magnet is a dipole. A magnet can be regarded as having two magnetic poles, one "north" and one "south". The end of a freely suspended magnet that starts to point towards the Earths geograpical North Pole, is by definition the magnetic north pole. Equally, the other end that ends up pointing towards the geographic South Pole, is the magnetic south pole.
However, if you were to cut a magnet in half, you would never get a north piece of magnet and a south piece of magnet. You would instead end up with two smaller magnets.
The Earth's magnetic field has a north and south pole. We can use the magnetic field of the Earth to help navigate by using a magnetic compass[?]. Compasses can also be used to figure out which side of a magnet is the north or south pole of that magnet.
See also:
Magnetic lines of force of a bar magnet shown by iron filings on paper |
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