Leonardo da Vinci designed a water screw to lift water with a continuous spiral surface.
His notebooks contain studies of screw-shaped devices for raising water, adapting a principle associated with the ancient Archimedes' screw. In a typical water screw, a helical blade turns inside a tube or trough; water trapped between the spiral and the housing moves upward as the screw rotates.
The underlying machine was not Leonardo's original invention. Ancient Greek and Hellenistic sources associate the water screw with Archimedes, traditionally dated to the third century BCE. Leonardo's contribution was to study, draw, and develop hydraulic machinery within his broader investigations of pumps, canals, mills, and water flow.
A water screw is different from the large aerial screw in Leonardo's flight sketches. The water device is a pump for moving liquid, while the aerial screw was a speculative flying-machine concept. Modern screw pumps still use the same general principle, though their materials, seals, and power sources are far more advanced.