Making magnets

There are two simple ways of making, say, a piece of iron magnetic. Magnetizing the iron lines up all the tiny molecular magnets inside it.

(a) Stroking it with another magnet to 'draw' all the like poles to one end.


(b) Winding a coil of wire round it and then passing a current (d.c. or ac.) through the wire. This is the method used today.

Demagnetizing a magnet

Banging a magnet will eventually destroy its magnetism as the regular arrangement of molecular magnets has been upset. It can also be can be demagnetized by heating it or slowly removing it from an a.c. field.