Archimedes

Little is known for sure about the Greek physicist and mathematician, Archimedes, except his dates and his home town. He was born in 287 BC and he died in 212 BC. He lived in Syracuse in Sicily. Yet has survived for over 2000 years. The story goes like this. King Hieron II of Syracuse asked Archimedes to find out whether a goldsmith had cheated him or not. The goldsmith should have made the king a pure gold crown but the king suspected that he had in fact used a mixture of gold and silver.

Archimedes worked out that the mixture would take up more space than the same weight of pure gold because silver is less dense than gold. But how could he possibly measure the volume of the crown? He found the answer when he was getting into his bath and slopped some water over the edge.  He realised that anything put into a tub of water would displace exactly its own volume. All he needed to do was to compare the level of water in his bath before and after he put the crown in. He was so excited by this idea that he ran naked through the streets of Syracuse crying ’Eureka’ which means ’I have found it!’

He went home and did the test. The crown displaced more water than a block of gold with the same weight. This proved that the goldsmith had tried to cheat the king.