A meteorologist measures weather patterns in the atmosphere to predict the weather forecast ahead of time. To track changes in the weather, a meteorologist uses weather instruments at a weather station. There are many different weather instruments, each made to measure a different feature of the weather:

• a thermometer to measure temperature
• a barometer to measure air pressure
• a hygrometer to measure humidity
• a rain gauge to measure precipitation
• an anemometer to measure wind speed
• a wind vane to measure wind direction

An anemometer is used to measure wind speed. Speed is how fast or slowly something is moving. But what exactly is wind? Wind is movement in the air that can be seen or felt. Wind occurs when air moves from a high-pressure area (where there are more molecules) to a low-pressure area (where there are fewer molecules). See the CYBERCHASE episode, by PBS KIDS GO!, and watch as the CyberSquad heads to the Northern Frontier to solve a mystery by measuring and comparing wind speeds! Then get ready to test winds yourself. In this experiment, you will make your own wind meter, or anemometer. An anemometer is useful because it rotates with the wind. To calculate the speed, or velocity, at which your anemometer spins, you will determine the number of revolutions per minute (RPM), or how many times the anemometer spins a full circle from where it started in one minute. To test your anemometer, you will set a fan at different speeds and count the revolutions per minute of your home-made anemometer. How well will it work?