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A weather station has special tools to measure temperature, pressure, wind and moisture in the air. Anemometers measure wind speed. Weather stations also help us forecast the weather in the days ahead.

Topics and Connections:

• Wind strength
• Weather instruments
• Making measurements

Materials:

• plastic protractor for each student
• ping-pong ball for each student
• string
• tape or glue
• pens
• variable-speed fan

Directions:

Students:

• Cut a one-foot length of string.
• Tape or glue one end of the string to a ping-pong ball, and tie or tape the other to the small hole at the center of the protractor's flat edge.
• Label the protractor as follows:
  – mark the 90° mark of the protractor "0 mph"
  – mark the 80° mark of the protractor "8 mph"
  – mark the 70° mark of the protractor "12 mph"
  – mark the 60° mark of the protractor "15 mph"
  – mark the 50° mark of the protractor "18 mph"
  – mark the 40° mark of the protractor "21 mph"
  – mark the 30° mark of the protractor "26 mph"
  – mark the 20° mark of the protractor "33 mph"
• To use this anemometer, hold it with the flat base at the top, so it's level. The ping-pong ball should hang straight down.
• Turn on a fan. Keep the protractor as far from your body as you can, so you're not blocking any of the wind.
• Aim the protractor so the ping-pong ball is blown along the side of the protractor, not into or away from it. You can measure the wind's speed by seeing which degree mark the string is pointing at.
• Try the different settings of the fan. How consistent are different student's readings?
• Go outside and try measuring the real wind.

Questions To Ask:

• How does this tool work?
• How steady is the wind?
• If you open a door or window in your classroom, is there a wind? How fast.?

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