-: MAKING AN ANEMOMETER :-

 An anemometer is an instrument used to measure the velocity of wind. The simplest anemometer has three or four cups attached to a vertical pipe. The wind catches the cups, spinning them around. The winds speed is measured by the number of times the cups go round in a certain period of time. Aeroplane pilots and sailors need to know the speed of the wind. A meteorologist makes use of anemometer for making weather forecasts.

*** MATERIALS REQUIRED ***       

•  Take one foot length of stiff wire.

       

• Bend one of its ends in the form of a loop.
• Fix this end at the bottom of the shoe box with tape.                                     

•  Place the lid on making a hole for the wire.
• Take two thin pieces of wood and make a cross

•  Push four paper cups onto the ends of the wooden cross, facing In a circle. 
• Tie a cotton thread to the pin in the side of the tube, leading it sideways over a roller. 

• Tie a small weight at the other end of the thread, just touching the ground.
•  Now, put the whole arrangement in a windy place and let the cups go. They should swing round in the wind. Use a watch to note the time, how long the weight takes to rise from the ground to the edge of the table. Now, divide this length by the time taken, and you will get, wind velocity.