An anemometer measures
the speed of wind.
Things required: 4 ice cream cups, paper, red and green
paint, glue, three wooden sticks(two of 25- 30 cm length and the
other of 40 - 45 cm length), a tall plastic bottle filled
with sand, pins.
Paint three ice cream cups green and one cup red.
Glue the two sticks of equal size at right angles. Secure them with
a pin. Glue the cups to the four ends of the sticks in clock wise
direction as shown in the illustration.
Fix the cross with the four cups to the bigger stick with the
help of a pin so that it can spin freely in the wind. And position
it in the plastic bottle filled with sand.
| Wind
speeds range from 5 km/hr in a light breeze to over 160 km/hr
in violent storms. So wind is a great source of power. We
harness this wind power in windmills for rotating millstones
and lifting water. Wind power is also used to generate electricity.
|
Put the anemometer outside.
To have a rough estimate of the wind speed, count the number
of complete turns the red cup makes in 30 seconds. Divide this
number by 10 to get the wind speed in km/hr. |