How to Build a Vane Anemometer

Professional anemometer

An anemometer is a device used to gauge the wind speed. It is a common tool of modern meteorology, and if you've seen a weather station, chances are you've seen them spinning in the wind. For backyard weather enthusiasts, they're an easy device to build and a common weather science project for kids. They can be built at almost any size, but for average use, they don't need to be very big.

Things You'll Need

• Wooden dowel Two wooden sticks, 18 inches by 1/2 inch Two glass or ceramic beads, hollow centers Four sturdy plastic cups, small diameter Nails, various lengths Wood glue Pencil

Instructions

1. Affix one cup, horizontally, to each end of the wooden sticks by gently putting a nail through the sides of the cup and into the end of the stick. Aim the cups in opposite directions on each end.

2. Arrange the sticks to form a cross shape, keeping the cups horizontal. Apply a little glue to the overlapping surfaces where the two sticks meet.

3. Mark the center of the cross pieces with your pencil. Align one bead under the center and one on top of it, so that there is a bead on each side of the center of the cross.

4. Drive the nail through the center of the beads and the crossed sticks, into the end of the dowel. Do not drive the nail in too tight; the device should spin freely when done.

5. Place the anemometer outside where it can be seen, but where the wind is not blocked from reaching it. The far end of a porch or deck, away from the walls of the house, will do.

Tips & Warnings

• If you use a longer dowel, the anemometer can be placed directly into the ground, so long as it is a good distance above the ground. A simpler version of this can be made by putting plastic or paper drinking cups onto the ends of the straws. It makes a good weather activity for kids.

• This will give you only a relative reading of wind speed, based on the number of revolutions per minute (rpm). To measure actual mph/kph wind speeds, you must convert the rpm of your anemometer, or connect it to a device that will do so. Some science retailers sell the necessary electronics for this.

Resources

• Maps of World: Anemomenters in meteorology
• Science Buddies: Kids' lesson plan for using an anemometer