Why do magnets stick to iron but not to copper?

How it works

Every material contains countless tiny 'mini magnets' that come from electrons inside atoms. In iron, these mini magnets gather in groups that can all swing to point the same way when a magnet comes near, so the iron is pulled in. In copper and aluminium, they mostly cancel each other out.

Every magnet has a north pole and a south pole. Two like poles push apart, while opposite poles pull together. Earth itself behaves like a giant magnet, which is why a compass needle swings to point roughly north and south.

Looks can fool you. Many stainless steel spoons and pots barely stick to a magnet, because other metals mixed into the steel change its inner structure. The only way to know whether something is magnetic is to test it with a magnet.

Where to see it in New Zealand

Many beaches on the North Island's west coast, such as Piha near Auckland, have black sand rich in a magnetic mineral called magnetite. Drag a magnet inside a plastic bag through it and black grains cling on. Ironsand like this has been used to make steel in New Zealand for decades.

Try it together

Grab a fridge magnet and test a spoon, a paper clip, foil, coins, a pencil and an eraser. Guess first, then sort them into 'sticks' and 'does not stick'. Keep strong magnets away from phones and bank cards, and away from little children who might swallow them.