Leonardo da Vinci designed an anemometer to measure the force of moving air.
His instrument used a light, movable plate that wind could push upward. The height reached by the plate indicated the strength of the air movement. Leonardo was interested in wind measurement partly because of his studies of flight, birds, and atmospheric motion.
An anemometer is now generally defined as an instrument for measuring wind speed, though early designs often measured wind force indirectly. Modern versions may use cups, propellers, ultrasonic signals, or heated wires. Leonardo's design was simpler and did not resemble every modern instrument.
The anemometer should not be confused with a barometer. A barometer measures atmospheric pressure, while an anemometer measures wind movement or speed. Leonardo's work belongs to the early history of quantitative meteorological instruments.