What are magnet? |Fun with magnets| Types of magnets

 Discovery of magnets

Magnets were probably discovered by greeks about 2500 years ago. According to a legend, a shepherd boy named magnes living in greece. One day he noticed that the iron tip of his stick got stuck to a large black Rock. This black Rock was named magnetite after magnes. It is also said that magnets were first discovered in magnesia. 

     What are magnets? 

A magnet is a material that attracts iron objects having iron. 

Magnetic material

Materials that get attracted towards a magnet are called magnetic materials. E. g. Iron, nickel, cobalt. 

Non-magnetic material

Materials which do not  get attracted towards a magnet are called non-magnetic materials. E. g wood, cotton, leather, plastic, etc. 

       Types of magnets

Naturally occurring magnets are natural magnets. E. g magnetite. 

Considering the usefulness  of magnets, they are now made artificially. Artificial magnets are man-made by using iron, cobalt and nickel. E. g disc shaped magnets, cylindrical magnets, bar magnets, etc. 

Artificial magnets are of three types:

Permanent magnets: Magnets that retain magnetic property for long period of time. 

Temporary magnets: some magnets, which retain their magnetic property for a short period of time. 

Electromagnets: It is a special types of magnets in which the magnetism is produced by a flow of electric current. 

         POLES OF A MAGNET

Magnet has two poles. These are called the North  Pole (N) and the South Pole (S). 

The iron filings are attracted more towards the region  close to the two ends of the magnets. These ends are the poles of the magnet. 

The power of a magnet is concentrated at its poles only. 

    Finding directions with a magnet

A freely suspended bar magnet always comes to rest in particular directions, which are the North-south directions. 

The end of the magnet that points towards the geographic North Pole of the Earth is called its Northseeking end or the North Pole of the magnet. 

The end that points towards the geographic South Pole of the earth is called the southseeking end or the South Pole of the magnet. 

The instrument that uses a magnet to find directions is called a  magnetic compass. 

Attraction and repulsion are important properties of a magnet, which are as follows:

1.Magnets attract objects such as iron and nickel. 

2.The force of attraction of a magnet is always greater at poles than in the middle. 

3. Like poles of two magnets repel each other. The North Pole  of one magnets repels the North Pole of another magnet. 

4. Opposite poles of two magnets attract each other. The North Pole of one magnet attracts the South Pole of another magnet. 

5. A magnet suspended freely in air with the help of a thread, its North Pole towards the South Pole points towards the South Pole of earth and vice-versa. 

 N S --> <----N S 

Opposite poles attract. 

N S <--- ---> S N

 Same poles repel. 

Attraction and repulsion in poles of two magnets.