Which instrument measures wind speed?

• A. Barometer
• B. Anemometer
• C. Altimeter
• D. Seismograph

Answer: (B)

Wind speed is measured with an instrument called an anemometer. Traditional cup anemometers have several cups that catch the wind; as wind blows, the cups rotate, and the rotation rate is proportional to how fast the air is moving. This rotation is translated into a wind speed reading. There are other designs too, like sonic or hot‑wire anemometers, which determine speed using sound travel times or heat transfer, respectively.

Barometers measure atmospheric pressure, which helps predict weather but doesn’t tell you how fast the wind is blowing. Altimeters estimate altitude by using air pressure changes with height. Seismographs record ground movements, such as earthquakes. So the tool that directly gauges how fast the air is moving is the anemometer.