Archimedes is know as one of the great scientists of antiquity mostly hailed for his mathematical work, his theories of mechanics and his clever use of machines in the defense of Syracuse against the Romans. It is believed he studied under followers of Euclid in Alexandria, Egypt before returning to his native Syracuse, then an independent Greek city-state.
It is in Syracuse that Archimedes famously experienced a moment of genius while taking a bath. From this experience, he came up with the simple yet useful idea that if an object plunged into liquid it becomes lighter by an amount equal to the weight of liquid it displaces.
Archimedes also worked out the principle of levers, developed a method for expressing large numbers, discovered ways to determine the areas and volumes of solids, calculated an approximation of pi and invented a machine for raising water (called Archimedes’ screw). According to legend, Archimedes used a series of machines to keep the Romans at bay for years during the siege of Syracuse. When the Romans finally made it into the city, Archimedes was killed by a soldier.