Anemometer2

= Make an Anemometer = = =


 * [[image:http://www.ciese.org/curriculum/weatherproj2/images/dixie.jpg width="200" height="200" align="right" caption="Anemometer"]]Materials**
 * 4 small paper cups designed for bathroom dispensers
 * 4 plastic drinking straws
 * tape
 * scissors
 * straight pin
 * pencil with a new eraser
 * stapler
 * Procedure**
 * 1) This anemometer has four cups which catch the wind and cause the anemometer to spin. The inward curve of the cups receives most of the force of the wind. That's what makes the cups move. The more spins per minute, the greater the wind velocity.
 * 2) Attach non-bending ends of 2 straws to create a double length straw. Attach the double length straws to form a cross and tape them together at the center.
 * 3) Poke a hole through 1 side of each cup. Insert bending end of straw through the hole. Bend the straw so the short end sticks out of the cup. Staple around the straw to the opposite side of the cup, so the open ends of the cups all face the same direction.
 * 4) Push a straight pin through the center of the straws. Push the pin through a small piece of paper (eraser sized) and then into an eraser on the end of a pencil. This provides the axle.
 * 5) Mark one of the cups; this will be the one they use for counting when the anemometer spins. NOTE: When using this anemometer, 10 turns per minute means the wind speed is about one mile per hour. If possible, it would very useful to use a commercial anemometer to determine an approximate determination. For example, "when our anemometer read 20 spins a minute, the commercial anemometer read 2 miles per hour."
 * 6) Blow on the anemometer or turn an electric fan on low to make sure that it spins easily. How many times the anemometer will spin in one minute? Can you make a statement connecting the number of spins of your anemometer and the speed of the wind? (you can use the table below to record your practice trials).

1 minute ||<  ||< **Number of Spins** ||< || Describe to the best of your ability how this device actually measures air pressure. Include the following terms in your description: pressure, force, kinetic energy, mechanical energy.
 * < **Time Interval**
 * < **1.** ||<  ||< 112 ||
 * < **2.** ||<  ||< 94 ||
 * < **3.** ||<  ||< 112 ||
 * How does it work?**

Kinetic energy in wind is converted to mechanical energy, via spinning on the axle. The force of the wind is exerting pressure on the cups.

What can you do to improve the functioning of this device? Can you improve the accuracy? Precision? Can you make the device more stable or portable? You may select any materials we have here today or suggest alternative materials. Be clear in your description as to why these modifications will improve this device.
 * Engineering Experience: Ideas for Improving the Design**