Portal:Physics/Selected picture/April 2014

Archimedes' screw, also called the Archimedean screw or screwpump, is a machine historically used for transferring water from a low-lying body of water into irrigation ditches. The screw pump is commonly attributed to Archimedes on the occasion of his visit to Egypt, but this tradition may reflect only that the apparatus was unknown to the Greeks before Hellenistic times and introduced in his lifetime by unknown Greek engineers. Some writers have suggested that the device may have been in use in Assyria some 350 years earlier.

File:Archimedes-screw one-screw-threads with-ball 3D-view animated small.gif|Archimedes' screw was operated by hand and could raise water efficiently

File:Arkimedes skruv i Huseby.JPG|An Archimedes' screw in Huseby south of Växjö Sweden

File:Archimedes screw.JPG|Archimedes' screw]

File:Archscrew.jpg|Roman screw used to dewater mines in Spain

File:IMG 1729 Gemaal met schroef van Archimedes bij Kinderdijk.JPG|Modern Archimedes' screws which have replaced some of the windmills used to drain the polders at Kinderdijk in the Netherlands

File:Schroef van Archimedes.jpg|Archimedes' screw as a form of art by Tony Cragg at 's-Hertogenbosch in the Netherlands