Eureka Springs -- I Found It!
More than 2000 years ago, King Hiero II of Syracuse asked the Greek mathematician Archimedes (287-212 BC), to determine the amount of silver in the royal crown.
Though the crown appeared to be made of gold, the King suspected that the goldsmith might actually have hidden a large percentage of silver in it. Archimedes was at a loss: How would he determine the "gravity" of the metal in the king's crown?
While bathing one day, the mathematician noticed that as he stepped into his bath, which was too full, there was a certain amount of water displacement that had overflowed upon the floor — and the answer instantly hit him. He realized that a crown made of pure gold would displace more water than would one made of an alloy with lesser weight.
He ran out stark-naked into the street, shouting "Eureka!
I have found it!" (perfect tense of the Greek word heuriskein, to find). Archimedes then went back to his bath, plopped himself down into the water, and thought to himself that he could determine the amount of silver that was in the stately crown: He could put the King's crown into the water, and then he could place equal amounts of gold and silver in the water separately and observe the difference in the displacement of water.