electro magnetic

A coil of wire with electricity flowing through it acts as a bar magnet. However, you can control magnetism, you can turn it on and off by using a switch to turn the current and off. You can also reverse the chaining the connections battery. Placing a piece of iron into the coil induces a magnetic effect in the iron when the current is flowing in the coil and so turning it into an electro-magnet to the polarity.

For primary science, all the investigations needed can centre around the simple electro-magnet. This can be made by winding about 20-40 tight, neat turns around an iron nail and connecting the ends of this coil to 1 or 2 torch-sized 1.5v batteries. Once used, the nail may retain some magnetism, even when the current is switched off.

When a wire carrying an electric current is moved in a magnetic field of a magnet the magnetic field induced by the wire reacts with the magnetic field of the magnet causing the wire to move outwards. Fleming s left hand rule helps you to predict the movement.