Leonardo da Vinci sketched an anemometer to show wind direction and strength.
An anemometer is an instrument for measuring wind speed, and some designs also indicate direction. Leonardo’s version used a lightweight plate that moved in the wind. The position of the plate could be read against a graduated scale, providing an estimate of how strongly the air was moving.
Leonardo studied wind because it affected flight, weather, water movement, and the operation of machines. His observations linked the instrument to his broader investigations of air resistance and the behavior of moving fluids. The design was not an electronic sensor and did not produce modern digital measurements.
The term is sometimes confused with a wind vane. A wind vane primarily indicates direction, while an anemometer is primarily associated with speed. Leonardo’s design is historically important because it applied a visible mechanical indicator to the measurement of an invisible natural force.