Leonardo da Vinci designed an anemometer, a device for measuring wind speed using a hinged plate.
His design used a light plate that the wind pushed upward against a graduated scale. The height reached by the plate indicated the strength of the wind. Leonardo recorded the concept in his notebooks while studying atmospheric movement and the practical problems of flight.
An anemometer is a general class of instrument, not a single design unique to Leonardo. Modern anemometers commonly use rotating cups, propellers, or electronic sensors instead of a hinged plate. Leonardo’s version is therefore best understood as an early wind-speed measuring concept.
The device is sometimes confused with a wind vane. A wind vane shows wind direction, whereas an anemometer measures wind speed. Leonardo investigated both flight and weather-related observations, making wind measurement useful to his broader studies of air.