Leonardo da Vinci’s anemometer measured wind strength with a swinging plate.
Leonardo designed the instrument while studying flight and atmospheric movement. Wind pushed against a flat plate, causing it to move along a graduated scale. The position of the plate gave an indication of the wind’s force, allowing observers to compare conditions rather than simply relying on sensation.
The device is an early form of an anemometer, the general name for an instrument that measures wind speed or wind force. Leonardo’s version was not the rotating-cup anemometer commonly seen today, and it did not provide the same standardized numerical readings used by modern meteorologists.
Its importance lies in converting a natural phenomenon into a measurable quantity. Leonardo needed such observations for his studies of birds, flight, and machines. The instrument should not be confused with a barometer, which measures air pressure, or a hygrometer, which measures humidity.