Archimedes. Coloured historical artwork of the Greek mathematician and physicist Archimedes (287- 212 BC) in his bath. Archimedes discovered the value of pi, the ratio between a circle's radius and circumference. He derived the formulae for the areas and volumes of a variety of shapes. Archime- des created the sciences of mechanics and hydrost- atics, showing that an object immersed in a fluid is supported with a force equal to the displaced fluid's weight (Archimedes' principle). He is supposed to have verified that a crown was made of pure gold without harming it. The idea to submerge the crown and compare its water displacement to an equal weight of pure gold occurred in the bath.