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Science Is a Breeze: Using Wind Tunnels

• Science is a Breeze: Using Wind Tunnels student sheet
• Science is a Breeze: Using Wind Tunnels student E-Sheet
• Instructions from The Measurement of All Things: Tools of the Aeronautics Trade-one copy for each student
• Clear adhesive tape
• Transparency film
• Glue
• Colored pencils or markers
• Box/window fan (3 speeds)
• Cardboard
• Strong scissors
• String
• Duct tape or packing tape
• 2 chairs
• Pencil
• Safety goggles
• Window screen (optional)
• Elastic cord (from a party hat)
• Toy cars

Gather all of the materials needed to construct the wind tunnel. Also, gather materials needed for the tests in the wind tunnel. You will want to test the shapes suggested at the above site (cone, cube, pyramid, and tetrahedron).

Collect at least five different cars for each wind tunnel. The cars should be of different styles such as a sports car, an SUV, and a van; ones that would have obviously different aerodynamic designs.

You may want to use the Science is a Breeze: Using Wind Tunnels student E-Sheet provided with this lesson. This online E-Sheet provides students with direct links to articles they should read, as well as the journal questions used in this lesson.


Motivation

In this lesson, students will explore wind tunnels and their importance in the development of flight, primarily through Laboratories of Flight: Wind Tunnels. Although this lesson touches upon aerodynamics, the main focus will be on technological issues.

Have students read the sections on A (very) Little History and Parts of a Wind Tunnel, found at the Observatorium's Laboratories of Flight: Wind Tunnels.

You may wish to discuss some of the new vocabulary words with the class before they read the article independently. A glossary is included in the teacher's guide to assist you.

Students can work in small groups to explore the resource, but have each student look for and write down answers to these questions in their science journals as they read:

• Why was bird flight not the best model for human flight?
• What does the settling chamber do?
• What is the role of the contraction cone, test section, diffuser cone, and drive section?
• What is considered the "input" of this system? What is the "output"?
• Why is a closed loop system an improvement over an open loop system?

Assign students to groups of three or four (depending on class size). Four groups are required to build a wind tunnel. If you have more than four groups, build two wind tunnels. Assign each group one of the "engineering tasks" as described in the instructions. After each group is finished with its portion of the wind tunnel, have the groups combine each part.

Next, conduct a discussion of the basic concepts of aerodynamics. To do this, show the class pictures of two different cars or trucks (one that is very aerodynamic, like a sports car, and one that is not, like an old VW van). Have them compare the shape of the two vehicles and ask them which one will have a greater drag and why. (Drag is affected by the velocity of the wind, and the cross sectional area of the object. The less cross sectional area being hit by the wind, the lower the drag will be. The wedge shape of a sports car will have a much smaller area than the flat front of the VW van.)

Now have students complete the experiments and questions from the activity on the website.

After students have completed the wind tunnels activity, they should test the toy cars in the tunnel for comparison. Have students use the Science is a Breeze: Using Wind Tunnels student sheet for instructions on how to test the toy cars and to help them organize the data that they collect.


Assessment

To assess student understanding of how a wind-tunnel system works, have each student answer these questions about the wind tunnels they built in their science journals:

• When a wind tunnel is working, what does it do? (It creates a high speed flow of air for testing the aerodynamics of various objects.)
• For the wind tunnel to work, must it receive any input? (It must receive air and electricity to run the fan.)
• What, if any, output does your wind tunnel produce? (It produces fast moving air.)
• Identify at least four parts of the wind tunnel. Describe what each part does, and tell how each part contributes to the system as a whole. (The settling chamber, contraction cone, test section, diffuser cone, and drive section are all parts of the wind tunnel.)
• Which of the parts that you have identified is the most reliable? Which is the least reliable?
• Could any of the parts of the wind tunnel you made be constructed of different material without affecting how the system works? Explain your answer. (Answers may vary.)
• If your wind tunnel stops working, how would you go about fixing it? (Answers may vary.)
• Could someone develop a computer simulation of your wind tunnel? Explain your answer. (Answers may vary.)

Created :10/20/2001