Wind Speed Meter
Gelsonlab HM-GC003 Wind speed meter wind vane anemometer cup wind speed
This colorful working model is sensitive to breezes as slight as 2 mph. Since it rotates at speeds 1/6 that of the wind velocity, wind speeds can be determined quantitatively by counting the rotations.
Includes four plastic molded cups, 3 black, 1 red for contrast; low friction axle; sturdy plastic base; instructions with sample problem and wind speed chart.