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Archimedes screw

166 bytes added, 23:19, 5 November 2012
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[[Image:archimedes screw.jpg|thumb|right|250px|Farmers in Egypt's Nile delta turn a traditional screw by hand to irrigate a field. Photo: [http://www.waterencyclopedia.com/Po-Re/Pumps-Traditional.html#b Waterencyclopedia.com]]]
[[File:Archimedes-screw one-screw-threads with-ball 3D-view animated small.gif|thumb|250px|Archimedes' screw was operated by hand and could raise water efficiently]]
The Archimedes Screw (named after a Greek mathematician) is though to have been around since 250 B.C.E.
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