How To Make An Anemometer

How to construct an Anemometer:

Materials Needed

• five 3 ounce paper cups
• two plastic straws(straight)
• pin
• scissors
• hole punch
• stapler
• pencil with eraser

Procedure

• Using a hole punch, punch one hole in only four of the cups, about a half inch below the rim.
• In the fifth cup punch four equally spaced holes about a quarter inch below the rim. Then, with the hole punch, punch a hole in the center of the bottom of the cup.
• Now, take one cup and push a straw through the hole. Fold the end of the straw, and then staple it to the side of the cup across from the hole. Do the same thing for the other one-hole cup, and the second straw.
• Slide one cup and straw assembly through two opposite holes in the cup with four holes. Push another one-hole cup onto the end of the straw just pushed through the four-hole cup. Now, you can bend the straw and staple it to the one-hole cup, make certain that the cup faces in the opposite direction from the first cup. Do the same procedure using the other cup and straw assembly and the remaining one-hole cup.
• Line up the four cups so each open end faces in the same direction (clockwise or counterclockwise) around the center cup. Now, push the straight pin through the two straws where they intersect. Push the eraser that's on the end of the pencil through the bottom hole in the center cup. Push the pin into the end of the pencil eraser as far as it will go. Now you can try out your anemometer.
• Your anemometer will rotate with the wind. To calculate the velocity at which your anemometer spins, determine the number of revolutions per minute (RPM). Next, calculate the circumference, in feet, of the circle made by the rotating cups. Multipy you RPM by the circumference of the circle, this will give you an approximation of the velocity of at which your anemometer spins (in feet per minute).