Fun With Magnets
Learning Goals
- Discovery of Magnet
- Types of Magnet
- Poles of Magnet
- Magnetic Compass
- Making your own magnet
Magnet: An object which attracts magnetic materials (like iron, cobalt and nickel) is called magnet.
Natural Magnet: Magnet which is found naturally is called natural magnet.
Artificial Magnet: Magnet which is made by humans is called artificial magnet.
Discovery of Magnet
Magnet was discovered by an ancient Greek shepherd, named Magnes. Once, while he was fiddling with his stick, the metallic end of the stick got stuck with the rocks. Those rocks contained the natural magnet, magnetite. The story of magnetite spread far and wide. Some people believe that magnetite was discovered at a place called Magnesia.
Types of Magnet
Magnets are made in different shapes and they are named according to the shape, e.g. bar magnet, dumb-bell shaped magnet, horse-shoe magnet, cylindrical magnet, etc.
Fig: Bar magnet
Fig: Horse Shoe magnet
Magnetic Materials
Materials which are attracted towards a magnet are called magnetic materials, e.g. iron, nickel and cobalt.
Non-magnetic Materials
Materials which are not attracted towards a magnet are called non-magnetic materials, e.g. aluminium, zinc, wood, rubber, etc.
Poles of a Magnet
A magnet has two poles, viz. north pole and south pole. The magnetic power is concentrated on the poles of a magnet. When a bar magnet is suspended to move freely, it always points in the north-south direction. The north pole of the magnet points towards the north and the south pole of the magnet points towards the south.
Fig: Interaction of poles of magnet
Interaction Between Poles of Magnet
- Like poles repel each other. This means when north pole of a magnet is brought near the north pole of another magnet, both repel each other. The same holds true for the south poles of two magnets.
- Unlike poles attract each other. This means when north pole of a magnet is brought near the south pole of another magnet, both attract each other.
Magnetic Compass
Fig: Magnetic compass
Use of Magnet in finding directions: Magnetic compass is a simple device which has been in use since ages; to find directions. Magnetic compass was discovered in ancient China. The sailors and travelers found magnetic compass very useful in finding directions.
Magnetic compass is composed of a small box with a glass top. The magnetic needle is placed on a pivot around which it can rotate freely.
Making your own magnet
With the help of a permanent magnet you can change a piece of iron into a magnet. For this, you need to place the iron piece on a flat surface. Then rub the permanent magnet on the iron piece for many times. Your hand movement should always be in the same direction, while doing this. After some time, the iron piece would attain magnetic property.
Storing a magnet:
- Bar magnets should be kept in pairs. Their unlike poles should be kept on the same side. A wooden piece must be placed between them. A piece of soft iron should be placed at their ends.
- For storing a horse-shoe magnet, you should place a piece of iron across the two poles.
- Magnets should be kept away from speakers, CD, television, music system, computer, etc.