Magnetism has been known to mankind for millennia. The ancient Greeks were familiar with materials, called loadstones, which could attract iron.  By the tenth century compasses made from loadstone were used by navigators from China and similar compasses were developed in Europe. In the late sixteenth century William Gilbert suggested that the earth is itself a giant magnet and it is for this reason that compasses work.

Magnets are well-known to all of us in our everyday life as we attach notes to our refrigerators with a variety of decorated fridge magnets. They are essential in the loudspeakers in our radios, televisions and mobile phones. Magnets are essential in our microwave cookers, we need them to store information on our computer discs and to produce pictures on our television screens.  In our hospitals the scanners used to make images of the insides of our bodies require very large powerful magnets.

In this primary session we investigate the magnetic field of a bar magnet using (i) iron filings (ii) a plotting compass. We also use some simple apparatus to demonstrate the magnetic field of an electric current.

PRIMARY: magnets and magnetic fields