Archimedes

Archimedes (c.287–212 BC), a native of Syracuse on the island of Sicily, was one of the greatest mathematicians who ever lived. In geometry he calculated the surface areas and volumes of various solids, such as the sphere and cylinder, investigated the ‘Archimedean spiral’, now written with polar equation r = k0, and listed the thirteen semi-regular polyhedra whose faces are regular but not all of the same shape. By considering the circumference of 96-sided polygons that approximate a circle, Archimedes proved that pi lies between 310/71 and 310/70 (= 22/7).
In applied mathematics he made outstanding contributions to both mechanics and statics. In mechanics he found the law of moments for a balance with weights attached, devised ingenious mechanical contrivances for the defence of Syracuse, and is credited with inventing the Archimedean screw for raising water from a river. In statics he observed that the weight of an object immersed in water is reduced by an amount equal to the weight of water displaced – now called ‘Archimedes’ principle’ – and used this to test the purity of King Hiero’s gold crown. On discovering his principle he supposedly jumped out of his bath and ran naked down the street shouting ‘Eureka!’ (I have found it!).
[Greece 1983; Italy 1983, 2013; Nicaragua 1971; Spain 1963]