ATTRACTION OF MAGNET
• Horseshoe magnet.
• Some water.
• Some sand
• A glass
1. Put the needle inside the glass and fill the glass with some sand.
2. Place the horseshoe magnet on the walls of the glass.
3. Now repeat the step using water instead of the sand in the glass.
4. Try to take out the needle out of the glass by pulling the magnet upwards.
When the glass is filled with water the needle is attracted to the magnet on the wall. It follows the movement of the magnet up the glass. But when the glass was filled with sand, it was not attracted to the magnet.
This happened because of underwater magnetism. The magnetic force also works in water. If the side of the glass were made up of any magnetic material, the needle would still be drawn to the magnet, but not with the same force. The reason being, part of the magnetic force would have been dissolved by the outer walls of the glass.