Leonardo da Vinci improved the anemometer, a device used to measure wind speed, while studying flight and air movement.
His design used a plate or vane that moved according to the force of the wind. By observing the position of the moving part against a graduated scale, a user could estimate wind strength. This information would have helped Leonardo investigate whether conditions were suitable for proposed flying machines.
An anemometer measures wind speed, whereas a wind vane indicates wind direction. A barometer measures atmospheric pressure, so it is another instrument with a related but different purpose. These distinctions matter because Leonardo’s notebooks contain many studies of air, water, motion, and measurement.
Modern anemometers commonly use rotating cups, propellers, or electronic sensors. Leonardo’s version was much simpler, but it represented the same basic engineering goal: converting wind force into a readable measurement.