An anemometeris an instrument to record wind speed and pressure, although, it can also give the wind’s direction. An anemometer is most commonly used in meteorology and aerodynamics. Knowing the prevailing winds in certain regions allows engineers to decide where to build a construction, such as a house or a building as this can prevent the construction from confronting prevailing winds during certain seasons. The construction of an anemometer requires the use of a few items that can be bought at the nearest hardware store or they can even be found around the house.
The things needed for the construction of an anemometer depend on whether you’re going to make a three cup or four cup anemometer. The three cup anemometer has a more constant torque than the four cup anemometer and responds more effectively to the prevailing winds. The three cup anemometer is the most currently used instrument in the meteorology industry for wind assessment studies. The following things will be needed for the construction of a three cup anemometer:
Things needed to make an anemometer
A flat table; a photographic tripod; a mini electrical motor that you can get from an unused radio; two feet of 20 gauge copper or metal wire; super glue or plastiline; three polystyrene cups, which you can get at a convenience store; a pair of pliers; red marker and masking tape. The tripod is going to serve as the stand for the anemometer. The electrical motor’s pulley is where the wire is going to be threaded, making the three wire arms and the cups are going to be attached to the end points of the wire arms.
Making an anemometer
Place the tripod with its three legs open over a flat table; take the small electrical motor and attach it, by using glue or plastiline, to the top of the tripod, with the pulley facing up. Measure and cut 24 cm (9.5 inches) of 20 gauge copper or metal wire; bend the wire at the center and thread the wire around the motor’s pulley, giving only one turn around the motor’s pulley. Make sure to spread out the two ends of the wire so that they are at 120 degrees from each other. Measure and cut 15 cm (6 inches) from another piece of copper or metal wire and thread it around the pulley and the other two wires, making sure to leave 12 cm (4.7 inches) on one end; spread the wire apart so that the three wires are 120 degrees apart from each other.
Function of an anemometer
The function of a three cup anemometer is very simple; the difference in wind pressure triggers the spinning of the motor’s pulley as the wind enters the orifice in the cup that is facing the direction in which the wind is coming. As the first cup travels 120 degrees from the point at which the wind started to push it away, the second cup’s orifice reaches the wind’s direction and is pushed away like the first cup. After the second cup travels 120 degrees, the third cup takes its place at the wind’s direction and is pushed away. The cycle starts again when the third cup reaches 120 degrees away from the wind’s direction.
Measuring the wind’s speed
To measure the speed of the wind, you have to measure the anemometer’s circumference and count the turns made in one minute. To do this, measure the distance of one of the wire arms from the axis, then, multiply that distance by 2 to get the anemometer’s diameter. Now multiply the diameter by pi (π) to get the circumference. Place your anemometer outside of your home and count the turns it makes in one minute. Multiply the number of turns by the distance traveled in one turn (circumference). Convert the result to feet by dividing by 12 and then, divide the result by 5,280 to obtain miles.
Where to place an anemometer
Most instruments for measuring the wind are usually placed on top of the roofs of buildings and houses. This allows for more accurate readings due to the influence of nearby buildings, trees and mountains. If you live in the city, place the anemometer on top of the roof of your house. If you live in the country, place it on top of a tall tree. According to the Franklyn Institute, an anemometer will give an approximate calculation of the circumferential velocity of the wind.