How to Determine Wind Speed with Dropping Sand

Build the Anemometer

• 1

  Place a 180-degree protractor on top of a piece of standard 8 1/2 -by-11-inch paper or cardboard. Use thick paper or cardboard so that it will stay stiff in the wind.

• 2

  Position the protractor so that the 0-to-180 straight line is parallel to the long edge of the paper.

• 3

  Trace a straight line with a pen or pencil along the 0-to-180 degree edge of the protractor. Mark the center of the line and label it as "center." Label each end of the line "0 degrees."

• 4

  Mark the paper every 5 degrees, moving along the arc of the protractor. Label each mark with its appropriate degree. The 90-degree mark should be perpendicular to the center mark. Be sure not to move the protractor while marking the paper. You only need to mark 0 to 90 degrees on one side of the protractor.

• 5

  Draw a line from the center mark to each degree mark. This will make it easier to read the anemometer.

Determine Angle of Drop and Wind Speed

• 6

  Position yourself so that you are facing the wind and holding the paper parallel to the direction of the wind. Hold a fistful of sand at the center mark of your anemometer. The 90-degree mark should be facing straight down.

• 7

  Release the sand from your hand slowly by letting it drop like a funnel through your fist.

• 8

  Watch the sand drop in front of the anemometer. Note the angle that the sand is dropping. For example, in no wind, it would drop straight down at 90 degrees. If the wind is blowing, the sand will be blown by the wind at an angle you can read on the anemometer.

• 9

  Use the following information to determine wind speed in miles per hr (mi/hr):

  90 degrees = 0 mi/hr

  85 degrees = 6 mi/hr

  80 degrees = 8 mi/hr

  75 degrees = 10 mi/hr

  70 degrees = 12 mi/hr

  65 degrees = 13 mi/hr

  60 degrees = 15 mi/hr

  55 degrees = 17 mi/hr

  50 degrees = 18 mi/hr

  45 degrees = 20 mi/hr

  40 degrees = 21 mi/hr

  35 degrees = 23 mi/hr

  30 degrees = 26 mi/hr

  And so on.