How can you measure wind speed? How is it related to weather conditions?

In this activity you build a simple anemometer, calibrate it, and monitor wind speed.

“Anemometer” is the name given to a device that measures fluid flow.

What causes wind? Are there specific conditions in your area that make it more or less windy? Does the wind usually come from a specific direction? Are there weather conditions associated with more or less wind?

Discuss these questions and write your answers below.

• ITSI probe kit motor and circuit
• 8" square of stiff paper to make a pinwheel
• Hot melt glue gun

1. Build the circuit for measuring rotational speed of the motor in the ITSI probe kit. Consult the
   activity. Here is a picture of the circuit.
   
2. Construct a pinwheel from a square piece of paper by cutting in along the diagonals and folding very other free corner into the center. Attach the corners with glue or tape.
   
   
3. Mount a carboard wheel on the motor shaft using hot melt glue.
4. Attach the pinwheel to the wheel with glue or tape.
   

1. Start recording voltage from the motor circuit. The voltage is proportional to the speed of the motor.
2. Blow on the pinwheel and test the signal.
3. Calibrate the pinwheel. You will need to be inventive to do this! Here are some ideas. Perhaps you can think of a better way.
   • Walk at a certain speed and record data while carefully carrying a laptop computer.
   • Wave the pinwheel with your arm if you can figure out the speed.
   • Use a fan and measure its wind speed by dropping something light into the air stream and see measure how fast it moves.
   • Have an adult drive a car (slowly!) in a parking lot and hold the pinwheel out of the window.
     Note: If the pinwheels are all made similarly, the motors should be similar enough to give the same results.
4. Use the new button on the left to collect multiple datasets.
5. Summarize your data by making a chart and a graph of voltage versus wind speed.

1. If you can use wires that are long enough to reach from the computer out the window, monitor the wind speed and direction.
2. Note the weather conditions associated with different wind speeds and directions.
3. Compare what you find with the weather, wind speed and direction reported on the news.

1. Describe how you calibrated your anemometer.
2. Describe the relationship you found between wind speed and voltage.
3. How well did your observations compare to weather news reports?

The following statement was found at "this site: http://www.kidsgeo.com/geography-for-kids/0087-wind-movement.php

Because wind is caused by the gases of the Earth’s atmosphere moving about in an attempt to equalize pressure, it seems natural to assume that wind would blow outward from areas of high pressure, towards areas of lower pressure. In a perfect world, free from other influences, this would indeed be the case. However, sometimes other factors can cause wind to blow differently than this expected pattern.

Go to the site and read more about the causes of wind patterns. Summarize what you find out.