Leonardo da Vinci studied a water screw as a device for transferring water between different levels.
The water screw uses a helical surface inside a cylinder or around a shaft. When rotated, the spiral carries water upward. Leonardo drew and examined screw-based mechanisms as part of his broader studies of hydraulics, machines, and water movement.
The underlying principle was not Leonardo's invention. The device is traditionally associated with Archimedes, who is said to have used or described a water-lifting screw in the third century BCE. Leonardo's contribution was his detailed Renaissance investigation and representation of mechanical systems, not the original invention of the principle.
A water screw should not be confused with Leonardo's aerial screw, which was a separate flight concept. The water screw works by moving liquid along a helix; the aerial screw was intended to generate lift by rotating through air. Their shared word refers to their spiral geometry.