How to Make a Simple Anemometer

An anemometer is an instrument that is used to determine the speed and direction of the wind. It is often used at airports or at weather stations. To create one yourself is realistically possible once the materials are gathered together.

The construction of an anemometer requires five three-ounce plastic cups, two plastic drinking straws, a pencil with a new, attached eraser, single-hole paper punch, scissors, tape, a push pin and a permanent marker.

To begin, punch one hole approximately one-half inch below the rim of four of the cups. The fifth cup will have two holes punched about one-half inch below the rim, so the holes are opposite each other. Two more holes will be punched half-way between the holes and one-fourth of an inch beneath the rim. When finished there will be two sets of holes opposite each other.

Using the scissors, punch a hole in the center of the bottom of the cup, so that the hole is large enough for the pencil to fit through. 

Use one of the cups that have one hole in it, insert one end of the straw into the cup and then bend the end of the straw, inside the cup, so it is bent one-half of an inch. Tape the end of the straw to the inside of the cup. The other end of the straw is placed through two of the opposite holes in the fifth cup. This straw is then to be placed through another of the single-hole cups. The openings of the cups should face opposite directions. Tape the end down as was done with the other end. The two cups should now be opposite each other.

With the remaining straw, insert it into the hole of a single-holed cup and repeat the previous paragraph. When finished each cup’s opening should be facing the cup in front of it. And the cups should be parallel to the floor.

The pencil, eraser-side up, is placed through the bottom of the cup which is holding the straws. Push the pin, carefully through the straws, where they cross and on into the eraser of the pencil.

Draw a large X on the bottom of one of the sideways cups with the permanent marker.

The anemometer works best when it is used in an open area and is held in front of the user. As the cups spin around, count the number of rotations the cup with the X makes in ten seconds. Two to four revolutions is one mile per hour; five to seven is two miles per hour; eight to nine is three miles per hour; ten to 12 is four miles per hour; 13 to 15 is five miles per hour; 16 to 18 is six miles per hour; 19 to 21 is seven miles per hour; 22 to 23 is eight miles per hour; 24 to 26 is nine miles per hour; 27 to 29 is ten miles per hour.

This is a fun project to introduce children to the forces of wind and its effect on the weather.