Archimedes was a mathematician, physicist, astronomer, engineer, inventor, and weapons-designer. Arguably, the greatest scientist in ancient Greece, certainly the greatest scientist of the classical age. He was a man who was both of his time and far ahead of his time. Archimedes is especially important for his discovery of the relation between the surface and volume of a sphere and its circumscribing cylinder. He is known for his formulation known as Archimedes’ principles. He quotes “a solid denser than a fluid will, when immersed in that fluid, be lighter by the weight of the fluid it displaces”. He also invented the Archimedean Screw to pull water out of the ground, the device is still used around the world. The story that he determined the proportionof gold and silver in a wreath made for Hieron by weighing it in water is probably true, but the version that has him leaping from the bath in which he supposedly got the idea and running naked through the streets shouting “Heurēka!” (“I have found it!”) is a popular phrase. Archimedes had many practical inventions at which he excelled and to which he owed his fame, however he left no written work on such subjects.