Why does a bar magnet align itself in one direction when suspended freely?
Bar magnet – A Dipole magnet
A bar magnet has two poles – the north pole and the south pole situated on its opposite ends.
It is therefore also known as Dipole magnet, where ‘di’ means ‘two’.
Dipole magnet
Earth’s magnetic field
The earth is like a huge bar magnet. It has two magnetic poles on the opposite ends. Its magnetic field originates from the centre of the earth and extends high into the sky.
Earth’s magnetic field
The magnetic north pole of the earth is its geographical South Pole. Similarly, the magnetic south pole is its geographical North Pole.
Bar magnet experiment
If we keep a small bar magnet on the surface of water with the help of a float, it comes to rest in the same position. No matter in whatever direction it is pushed, the magnet always aligns itself in the North-South direction. This is because of the Earth’s magnetic field.
We know that opposite poles attract each other. Therefore, the south pole at the earth’s geographical north attracts the north pole of this magnet and the north pole at earth’s geographical south attracts the south pole of the magnet.