Wind velocity or speed is measured by a cup anemometer, an instrument with three or four small hollow metal hemispheres set so that they catch the wind and revolve about a vertical rod.
Time Required: An afternoon
- The anemometer cups are made from the aluminum. Cut 2 circles about 4 inches in diameter.
- Cut the circles in half along the diagonal
- Join the straight edges with aluminum solder, making 4 small cups
- Attach the cups to 2 crossed sticks, so that all are heading in the same direction
- Join sticks to dowel stock as follows: Nail, glass bead, crossed sticks, glass bead, dowel stock
- The glass beads will act as bearings so the wind will turn the anemometer freely.
- The anemometer will spin faster as the force of the wind increases.
- See diagram to the left.
What You Need
- Thin sheets of aluminum (or cardboard)
- Dowel stock - round wooden rod
- 2 glass beads
- 2 thin wooden sticks, 18 inches x 1/2 inch
- Aluminum solder