Wind speed is an essential variable needed to accurately characterize weather conditions. Professional weather stations will use sophisticated devices, which can measure wind speed accurately to within a few miles per hour. A much simpler way to measure wind speed is with a ribbon tied to a stick. Once calibrated, the device will allow the casual kite-flyer or sailor an indication of the wind speed.
- 3 Ribbons, 1 centimeters wide and 25 centimeters long
- Electrical tape
- Stick 1 centimeters wide and 25 centimeters long
- Graph paper
- Hand-held anemometer
Place the three ribbons on top of each other and tie them together on one end.
Tape the ribbons onto the end of the stick so that the knot is protruding above the tape.
Take the device to an outdoor area with enough open space to let the wind blow without turbulence.
Hold the stick up in the air and let the wind blow the ribbon such that it points at an angle relative to the stick. Take note of the approximate angle between the ribbon and the stick.
Turn on the hand-held anemometer, and hold it up into the direction of the wind so that the impeller -- the device that rotates in the wind -- starts to rotate. Take a note of the wind speed value shown on the digital display.
Record 20 measurements of angle versus wind speed and write them down.
Draw a graph of wind speed against ribbon angle. Write the y-axis title as "Wind Speed/mph" and the x-axis title as "Angle/Degrees." For each angle measured on the ribbon, plot the corresponding wind speed. This calibration graph can now be used with the ribbon to estimate wind speed independent of the anemometer.
Things You'll Need
- Photodisc/Photodisc/Getty Images