An anemometer is a device that tells you how fast the wind is blowing. The device you can build is a model of a wind speed indicator. A real one will be able to accurately measure how fast the wind is blowing. Yours will give you only approximation of how fast it‘s blowing. It can‘t give you an exact wind speed.
Materials:
- Scissors
- 4 small paper cups (like drinking cups)
- A marking pen (any color)
- 2 strips of stiff, corrugated cardboard --the same length
- Ruler
- Stapler
- Push pin
- Sharpened pencil with eraser on the end
- Modeling clay
- A watch that shows seconds
Procedure:
- Cut off the rolled edges of the paper cups to make them lighter.
- Color the outside of one cup with the marking pen.
- Cross the cardboard strips so they make a plus (+) sign.
- Staple them together.
- Take the ruler and pencil and draw lines from the outside corners of where the cardboard strips come together to the opposite corners. Where the pencil lines cross will be the exact middle of the cross.
- Staple the cups to the ends of the cardboard strips; make sure the cups all face the same direction.
- Push the pin through the center of the cardboard (where the pencil lines cross) and attach the cardboard cross with the cups on it to the eraser point of the pencil.
- Blow on the cups to make sure the cardboard spins around freely on the pin.
- Place the modeling clay on a surface outside, such as a porch railing, wooden fence rail, a wall or a rock.
- Stick the sharpened end of the pencil into the clay so it stands up straight. Your anemometer is now ready for use!
Measuring Wind Speed
This anemometer cannot tell the wind speed in kilometers per hour, but it can give you an idea of how fast the wind is blowing. Using your watch, count the number of times the colored cup spins around in one minute. You are measuring the wind speed in revolutions (turns) per minute. Weather forecasters‘ anemometers convert the revolutions per minute into kilometers per hour). Keep a record of the wind speeds you‘re measuring for the next few days. Measure the wind speed at different times of the day. Is it the same in the morning; the afternoon; the evening? Move your anemometer to another location. Is it windier in other places? Do trees or buildings block the wind?