Aeronautics Research Mission Directorate 

Build an Anemometer

 

Suggested Grades: 3-8 

Activity Overview

Weather, including wind, is a very important thing to 

consider when flying an airplane. In this activity, you 

will build an anemometer, which is an instrument used 

to measure wind speed.

Note: For this activity, you will be inserting a pin 

through the straws and into an eraser. You may need to 

ask an adult to help you with this. 

Steps

1. Make a cross with two plastic drinking straws. 

Tape them together so that the cross has four 

legs of equal length. See Figure 1. 

Figure 1. Use tape to hold the straws together

Time: 30 minutes

Materials

• Four small paper cups

• Two straws (nonflexible)

• Tape

• Stapler

• One long pin such as a sewing 

pin, t-pin or other pin long enough 

to go through the straws and 

firmly into the pencil eraser

• One pencil with eraser

• One marker
2. Push the pin through the center of the cross and into the eraser of the pencil. This will 

create the axle and provide something to help keep the anemometer attached to the base.

See Figure 2. Hint: Spin the straws several times, both clockwise and counterclockwise, 

to slightly widen the hole that the pin made in the straws. This will allow the anemometer 

to spin more freely in the wind. You can also make the hole larger by moving the pin in 

and out several times.

Figure 2. Attach the straws to the pencil with a pin

3. Staple a paper cup to each leg, ensuring they all point in the same direction. See Figure 

3. Also, it is a good idea to add tape to help keep the cups attached and pointing in the 

correct direction.

4. Using the marker, clearly mark one of the cups so it is differentiated from the others 

while spinning. See Figure 3. 

Figure 3. Attach the cups to the straws using a stapler
5. Place your anemometer into a steady source of wind, such as a fan, an air vent or the 

wind outside. Count the number of revolutions the anemometer makes in one minute by 

counting how many times the marked cup passes. See Figure 4. 

Figure 4. Place the anemometer in a stream of air to see it rotate

6. If possible, try placing your anemometer into streams of air that move at different speeds. 

Did it rotate faster or slower with different winds speeds? 

You Might Want to Try: 

• On a windy day, take the anemometer outside and count how many revolutions it makes 

in one minute. If you can find the actual wind speed, you can figure out how many 

revolutions each mile per hour of wind is. 

• If you can find different sized paper cups, try making an anemometer with them, and see 

how the revolutions change in the same stream of air with different sized cups.

Background Information

Weather is the state of the atmosphere with respect to wind speed and direction, temperature, 

moisture and pressure. A pilot needs to consider all of these things while flying since each has a 

significant impact on the ability of both the airplane and the pilot to perform properly. Weather 

also impacts rocket launches since the rocket needs to pass through Earth’s atmosphere on its 

way to space.

Weather is primarily driven by temperature and moisture differences between two places. The 

different temperatures affect the pressure of the air, which causes the warm air from the high

pressure areas to move to areas of low pressure. This movement of the air is what we refer to as 

wind. 
Wind direction and speed play important roles for an aircraft in flight as well as and during 

takeoff and landing. Aviation weather reports include information for both surface winds and 

winds aloft, or the winds at altitude. When taking off or landing, a pilot ideally wants what is 

known as a headwind, where the air flows opposite to the direction of travel. This enables the 

aircraft to use less runway, or to carry more weight into the air. Having a headwind while in 

flight, though, will make the plane slower and burn more fuel; therefore, during flight a tailwind 

is preferred. The opposite of a headwind, a tailwind is when air flows with the direction of travel.

One final term that pilots refer to is a crosswind. While having little effect on a flight while 

cruising, a strong crosswind, or wind blowing from the side of the aircraft, makes landing more 

difficult as it is harder to keep the aircraft aligned with the runway.