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Discovery of Magnet

Around 600 BC, a Greek man, called Thales, found a rock which attracts bits of micro iron pieces towards it. However, he was surprised and named this rock as 'magnetes' after the town Magnes where it was found. The rock he found was an iron ore but other substances act in the same way. We call them magnets. Materials which are attracted to a magnet are said to be magnetic. Iron and cobalt are the best examples of magnetic materials.


Knowing about the poles of magnet is quit interesting. First we have to look into following images which illustrated two magnets.👇



First one is known as a horseshoe magnet and the second one, is known as a bar magnet. If some small pieces of iron are put near either of these magnets most of them will cluster around the ends of the magnet. This means that the magnetic effect is strongest at the ends. These are known as the poles of the magnet. If you suspend a bar magnet by tying a thin piece of thread around its centre you will find that it always points in the same direction. One end will always point north. This is known as the North Pole of the magnet; and the other end points towards the south and is known as the south pole of the magnet. The poles of magnets have other strange properties. If you put the North Pole of a magnet near the South Pole of another magnet they will pull or attract each other. However, if you put the north poles of two magnets close together they will push away or repel each other. A south pole will attract a north pole but repel a south pole.




Our Earth has two geographic poles, Northern and Southern poles. If we could draw a line between these two poles it would pass through the centre of the Earth. It would also lie along the axis about which the Earth rotates. The Earth acts like a giant magnet and so also have north and south magnetic poles. The magnetic poles are not always in the same place. At the moment the Earth`s south magnetic pole is about 1,900 km (1,180 miles) away from the Earth`s geographic south pole. So there is more than one answer to the question where is the Earth`s south pole...! An imaginary line drawn between the Earth`s magnetic poles would not necessarily pass through the centre of the Earth. 



A compass needle points to the Earth`s magnetic poles. The navigator wants to know his direction in relation to the geographic poles. So he has to know the distance between the geographic and magnetic poles to correct his compass reading.

 







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