Magnetic coppers
Feel the Force / Party Tricks

Sure, copper isn't magnetic. So why does the magnet pick up these pennies?

Age range 7-14


• Loads and loads of 1p and 2 p coins. Make sure you have coins from several different years.

• A magnet






• Before you start the experiment, think about what ‘copper’ coins are made of and whether you think they are magnetic or not.
• Spread the coins out and wave the magnet over them. Does the magnet pick up some of the coins?

• Did you think the coins would behave like this? Did you see a difference in the way some coins behaved? What’s going on?


Pennies and two pence pieces used to be made out of bronze, containing 97% copper, 2.5% zinc and 0.5% tin.

Some years ago, the cost of the expensive copper going into a coin became more than the coin was worth. If clever chemists realised this they would be able to melt the coins down and make money out of the copper. So to stop this happening, the Royal Mint started to make coins out of cheaper steel discs and then coated them to look as if they were still copper.

Coins made after this time are magnetic, and coins made before this time are not.



If you have enough coins, you can try to find out when the change was made.

Hint: the change was made sometime in the early 1990s.

You might also be able to spot another difference between the coins. The steel coins have to weigh the same as the copper ones, but copper is denser than iron. So the copper coins are slightly thinner. Can you see the difference in thickness if you hold a new copper next to an old one?


Terry Horsman, teacher at Lincroft Middle School in Oakley, Bedford, who learnt about it at an ASE meeting. Peter Borrows (from CLEAPSS School Science Service) pointed out the difference in thickness to us.