Everyday uses of magnets
Physics · Key Stage 2 · The School
Magnets holding things shut
A fridge door often closes with a hidden strip magnet. It pulls the door shut against the metal frame, without any latch to click. A pencil case or a handbag can close the same way. This use relies on a simple fact. A magnet pulls certain metals towards it, even through a thin layer of plastic or fabric.
Magnets sorting things out
A recycling centre uses a giant magnet on a crane. It lifts steel cans and scrap out of a pile of mixed rubbish, leaving aluminium and plastic behind. This works because steel is magnetic and aluminium is not, even though both are metal. Sorting by magnetism is fast, and needs no one to check by hand.
Magnets that carry information
An old-style swipe card, like some hotel keys, has a strip of tiny magnetic patterns recorded on it. A machine reads the pattern as the card slides through. The magnets themselves are too small to see. But a reader can still detect their pattern. That is why a strong magnet nearby can sometimes wipe a card by mistake.
A lunchbox lid needs to close firmly. It also needs to open easily with one hand, without a stiff clip that a small child struggles with. A hinge alone would let the lid flap open. A magnet built into the rim pulls the lid shut the moment it is close enough. It needs only a light pull to open again. The magnet was chosen not because it looks clever. It solves this exact problem better than a clip or a simple hinge would.