Properties of Magnets

History of Magnets

Earth's Magnetic Pole

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Do you know that the "geographical north" of the earth is actually the "magnetic south" of the earth. For a video explanation, click here to watch.

In fact the magnetic poles do not coincide with the geographic poles! This is because the magnetic poles move.

On every point on Earth, there is a difference of a few degrees between the geographical north pole and the magnetic north pole. The difference is called magnetic declination and it changes slowly as time goes by. This is because magnetic poles move.

Properties of a Magnet

Magnetic Field Lines

Testing a magnet
Attraction can confirm whether a specimen is a magnetic material, it does not tell us whether a specimen is a magnet.
Only repulsion can confirm that a magnetic material is already magnetized.

Take an example of a paper clip. When a magnet is placed near it, the paper clip is attracted to the magnet. However, it is obvious that the paper clip is not a magnet! It is merely made of magnetic material and was induced with magnetism when placed near a magnet.

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Hence, only repulsion can confirm that the object is a magnet!