Leonardo da Vinci designed an anemometer to show and measure air movement.
An anemometer is an instrument for measuring wind speed or, in some forms, indicating wind movement. Leonardo’s design used a light, movable element that could respond to airflow, helping an observer assess the force of the wind. He studied the device in connection with his broader investigations of flight and atmospheric conditions.
Leonardo’s instrument was an early conceptual step in wind measurement, not the cup anemometers commonly seen on modern weather stations. A barometer measures air pressure, a thermometer measures temperature, and a hygrometer measures humidity; those instruments answer different questions. Leonardo’s interest in the anemometer came from a practical aviation problem: a flying machine would need to account for the behavior and strength of the surrounding air.