## Archimedes Screw - Invented by Archimedes

: c.250 B.C.E
: Italy
: Agricultural

The invention of the water screw is credited to the Greek polymath Archimedes of Syracuse in the 3rd century BC.A cuneiform inscription of the Assyrian king Sennacherib (704 - 681BC) has been interpreted by Dalley to describe the casting of water screws in bronze some 350 years earlier. This is consistent with the classical author Strabo who describes the Hanging Gardens as watered by screws. A contrary view is expressed by Dalley and Oleson in an earlier review.The German engineer Konrad Kyeser, in his Bellifortis (1405), equips the Archimedes' screw with a crank mechanism. This mechanism soon replaced the ancient practice of working the pipe by treading.

Archimedes was a mathematician and inventor from ancient Greece. He discovered the relation between the surface and volume of a sphere and its circumscribing cyclinder (he had discovered pi). He then formulated a hydrostatic principle based on that mathmatical relationship called Archimedes' principle. He inventing the Archimedes screw - a screw-shaped machine or hydraulic screw that raised water from a lower to a higher level. Archimedes also invented the catupult, the lever, the compound pulley, and the burning mirror (a system of mirrors that burned the boots and ships of invading armies by focusing the sun's rays). Although Archimedes is credited with inventing the screw in the 3rd century BC, his screw was not like today's screw fastener but actually two other screw-type devices.

Archimedes' Screw has been used to lift water to higher levels since ancient times. Archimedes (287-212 B.C.) is the traditional inventor of this device, which was originally used for irrigation in the Nile delta and for pumping out ships. I have seen a nineteenth century Archimedes' screw still at work pumping water in a windmill at Schermerhoorn in the province of North Holland in the Netherlands. It lifted the water a vertical distance of 1 meter.

An analysis, using the lifting of marbles instead of water, is used in almost all nineteenth century texts. The lower end of the helical tube dips into a dish of marbles and scoops one up. The helix continues to revolve, and the marble is continually being lifted a short distance up an inclined plane. The frictional forces are small, and the marble keeps rolling down an infinite succession of inclined planes formed by the revolving helix. At the same time the marble resides at the local low spot on the helix, and is carried up the slope by forces perpendicular to its local motion.

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: http://en.wikipedia.org/wiki/Archimedes%27_screw