Portal:Physics/Selected picture/July 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, although some writers have suggested the device may have been in use in Assyria some 350 years earlier.

Images (from left to right):

Archimedes' screw was operated by hand and could raise water efficiently	An Archimedes' screw in Huseby south of Växjö Sweden	Archimedes' screw
Roman screw used to dewater mines in Spain	Modern Archimedes' screws which have replaced some of the windmills used to drain the polders at Kinderdijk in the Netherlands	Archimedes' screw as a form of art by Tony Cragg at 's-Hertogenbosch in the Netherlands