Leonardo da Vinci designed a water clock that used flowing water and a floating weight to measure time.
His studies of timekeeping included a device in which water moved through a container and caused a float to rise. The float’s movement could be linked to indicators or mechanisms that displayed elapsed time. Such designs applied hydraulic behavior to a problem usually addressed by sun position, sand, or mechanical escapements.
A water clock must regulate flow carefully if it is to keep consistent time. Changes in water level, temperature, evaporation, leakage, and container shape can affect accuracy. Leonardo’s drawings explored these engineering issues, but they do not show that his design became a widely used clock.
The concept should not be confused with a mechanical watch. Water clocks measure time through controlled liquid movement, while mechanical watches use stored energy and an escapement. Leonardo investigated both hydraulic and mechanical systems as part of his broader study of machines.