A machine sorts coins.
Each coin rolls down a sloping ramp past a strong permanent magnet. Coins made of a magnetic material are pulled sideways towards the magnet and fall into tray A. Coins made of a non-magnetic material roll straight on into tray B.
Some coins are made of steel with a thin copper coating. Other coins are made of bronze, which is a mixture of copper and tin.
Explain which tray each type of coin falls into.
A coin made of pure nickel is put into the machine.
Predict which tray the nickel coin falls into.
Give a reason for your answer.
Explain why the magnet must be a permanent magnet made of a material such as cobalt steel, rather than a piece of magnetised iron.
The magnet is turned round so that its other pole faces the ramp.
Explain why the machine still sorts the coins correctly.