|MadSci Network: Science History|
This is traditionally attributed to Archimedes, the great Greek engineer. It is
said that he was working on a problem involving density (specifically it was how
to detect when gold, a dense metal, has been adulterated with silver, a less
dense metal). He noticed that when something is immersed in water it pushes its
own volume of water out of the way. The object he immersed was supposedly his
body, and he is reputed to have run naked through the streets shouting,
Try the links in the MadSci Library for more information on Science History.