A variety of instruments can be used to measure wind direction, such as the windsock and wind vane.[2] Both of these instruments work by moving to minimize air resistance. The way a weather vane is pointed by prevailing winds indicates the direction from which the wind is blowing.[3] The larger opening of a windsock faces the direction that the wind is blowing from; its tail, with the smaller opening, points in the same direction as the wind is blowing.[4]