When you have finished this page, try the Wind Quiz. Wind is the movement of air around the earth. It is basically caused by the uneven heating of the earth's surface. Warmer, lighter air is pushed along by heavier, cooler air.
Wind direction is measured by a wind vane which is an arrow mounted on top of an elevated site.
The wind vane is designed so that its arrow points into the wind. With a compass aligned with the arrow, one can determine the direction of the wind. Wind speed or velocity is measured with either an anemometer or radar. The anemometer, pictured above, consists of several cups mounted sideways and extended out on a rotating axis or pole. The cups catch the wind and the more turns of the attached cups, the greater the wind speed.