Archimedes (about 287-212 BC) was an ancient Greek scientist. He was born in Syracuse (Sicily).
His scientific work was in mathematics, mechanics, physics and astronomy. He was the author of many inventions and discoveries, in particular a machine for irrigating fields, the screw, levers, pulley blocks and screws for lifting heavy loads, military throwing machines and so on.
He worked out the scientific foundations of statics; in particular he introduced the concept of the centre of gravity and of the moment about a line and about a plane, determined the position of the centre of gravity of many bodies and figures (the triangle), derived the laws of the lever mathematically and formulated the rule for the addition of parallel forces.
He laid the foundations of hydrostatics. His work “On Floating Bodies”, which has come down to us in translation, contains the basic propositions of hydrostatics, in particular its fundamental law (Archimedes' principle). Using this law Archimedes solved the problem of the gold and silver content of the crown of Hieron, king of Syracuse. In the same work he studied the equilibrium of floating bodies and derived the conditions for bodies to float.