Leonardo da Vinci designed an anemometer to study the strength and direction of air.
An anemometer is an instrument for measuring wind speed, and some forms also indicate wind direction. Leonardo’s version used a hinged plate that was lifted by moving air. A scale beside the plate could show how strongly the wind pushed it, providing a way to compare air currents.
Leonardo’s interest in wind measurement was closely connected with his studies of flight, weather, and the movement of projectiles. Quantifying air rather than merely observing it helped him investigate why wings generate lift and how wind affects machines. His design was an early mechanical approach to a problem that later instruments addressed with rotating cups, vanes, and electrical sensors.
The device should not be confused with a barometer. A barometer measures atmospheric pressure, while an anemometer measures wind. Leonardo’s instrument also predates modern weather stations, which combine wind speed, direction, temperature, pressure, and humidity measurements.