Weather Academy: DIY Anemometer, Measure Wind Speed at Home

MONROE, La. (KNOE) - Last week on the Weather Academy, we talked about wind, and Sheena taught us all about different types of severe wind damage. This week, we will conduct an experiment to make an instrument that measures wind called an anemometer. This DIY anemometer will allow for us to measure the wind speed ourselves.

What you’ll need:

Five small dixie cups
Two straws
Scissors or hole punch
Pencil with an eraser
One thumbtack

Steps:

Take one of the dixie cups and poke four evenly spaced holes around the edge. These holes should all be the same distance away from the edge of the cup and directly across from each other.
Take two straws and criss-cross them through the holes that we punched in the cup. You want the straws to overlap in the center of the cup.
Make a hole in the bottom of the cup at the very center. Make sure that the hole is the size of your pencil.
Insert the pencil, eraser first, into the hole that we just made. You want the eraser to touch the point where the straws overlap.
Poke the pushpin through the cross-section of the two straws and into the pencil’s eraser. You want to make sure that it is loose enough that the cup can still rotate.
Make two holes in the remaining 4 cups. Make sure that these holes are opposite each other and are the same distance from the lip of the cups.
Connect the cups to the ends of the straws. Make sure that every cup is facing the same direction.

An anemometer is an instrument that is used to measure wind speed. The open sides of the cups “catch” the wind more than the closed sides. This means that when the wind blows, it pushes harder on one side of the anemometer, causing it to spin. The anemometer’s rotation speed can then be used to determine the wind’s speed. Real anemometers are calibrated, meaning that a certain rotation speed corresponds to a known wind speed. They usually display the wind speed in miles per hour (mph). In this experiment, To measure the wind speed, count the number of times the anemometer makes one complete rotation in 30 seconds. Then we will multiply this number by 2, giving the wind speed in rotations per minute. Five turns in thirty seconds is equal to 1 mph of wind speed. Marking the bottom of one cup will help in counting the revolutions.

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