Here is a brilliant scientific craft / experiment - making your own anemometer out of paper cups and sticks, and them learning how to measure the wind speed. You will end up with a very rough answer but a good understanding of how a real anemometer works!
You will need:
- 3 thin sticks (garden canes or skewers)
- 5 paper cups
- Plastic bottle
- Electrical tape
Cut two of the sticks to the length of 34cm and mark them in the middle.
Cutting the sticks for our anemometer
Take one of the cut sticks and push each end through both sides of a cup. Use tape to secure the cups in position as shown on the photo. Repeat with the other stick and two more cups.
Paper cups on our cut sticks
Mark one of the cups to make it easy to count. We used a different colour cup to make it easier still.
Tape the sticks together in the middle so all the cups are facing the same direction.
Tape the third stick to the middle of the 'wheel' at right angles.
To make the base, fill the bottom of the bottle with sand or gravel for weight. Put the fifth cup upside down on top of the bottle. Poke the stick through the top of the cup.
Ready to count
Stand the anemometer outside where it can catch the wind. Using a stop watch to help you count how many spins in a minute. You count every time the marked cup reaches a particular point.
You can roughly estimate the windspeed in km/h by multiplying the number of spins in a minute by 60 and then dividing the answer by 1000. The answer is a very rough estimate!