Everyday uses of magnets
Chemistry · Key Stage 2 · The School
Magnets are everywhere, mostly hidden
A magnet does not have to look like a horseshoe. Fridge doors use a hidden magnet to stay shut. Bag clasps do too. So do cupboard catches. Each one uses the simple pull of a magnet.
Finding direction
A compass needle is a small magnet. It can spin freely. The Earth has its own weak magnetic field. The needle lines up with it. It points roughly north. Sailors have used this trick for hundreds of years.
Recycling plants use big magnets. Suppose a belt carries just ten cans under a big magnet. Six cans are steel and four are aluminium. Nobody needs to read a label. Step one: a steel can passes under the magnet. The steel in these cans is magnetic, so the magnet pulls the can up off the belt. The same happens to all six steel cans. Step two: an aluminium can passes under the magnet. Aluminium is not magnetic, so nothing pulls it. All four stay on the belt. Now check the count. Six pulled out plus four left makes ten, so no can was missed. The result is six steel cans in one bin. The four aluminium cans go on to other machines.
Magnets inside machines
A speaker has a magnet inside it. The magnet pushes against a coil of wire. That makes the coil vibrate. The vibration makes sound. It is the same pull you tested with a bar magnet, just doing a new job. Headphones use the very same trick, only much smaller. A tiny magnet, hidden inside, is doing real work every time you listen to music.