Credit Archimedes for His Role in Taking Down Rome

Think of Archimedes (c287–212/211 BC), and I bet the image you have is that of a man jumping naked out of his bath, running down the street shouting “Eureka!” (ancient Greek for “I have found it”). That's certainly the way he is depicted in the Horrible Histories' Groovy Greeks book.

It is for this bizarre episode that Archimedes is probably most famous. He was given a task to find out whether a crown had been made with solid gold, or whether the maker had deceitfully substituted some of the gold for silver, keeping the rest for himself. In essence, Archimedes had to work out the density of the crown, but without damaging it. Given that it was irregularly shaped, he first had to come up with a novel way of calculating its volume. He did this by measuring how much water was displaced when the crown was submerged – an idea that supposedly came to him when he got into his bath and saw water being displaced by his own body. This gave him the crown's volume, which he then used to divide its mass and find its density.