Wind tunnels are used to study the impact of an airstream on anything like aeroplanes and cars that will encounter wind. The wind tunnel allows an engineer or physicist to see how the wind interacts with her design. The amateur scientist or science fair participant can use a wind tunnel for designing or modifying models designed for flight or aerodynamics. Science teachers traditionally use them in the classroom to demonstrate principles like convection currents or lift. For clear viewing, a bit of smoke is needed to illustrate the wind as it interacts with the model.
- Skill level:
- Moderately Easy
Things you need
- Drill with 1/4 or 1/2 inch bit
- Coffee can
- Smoke bomb or smoke wand
If your wind tunnel does not already have a smoke hole, you will need to drill one or several. Make sure you drill the hole upstream from where the model you wish to test will be mounted. The hole should be drilled at the bottom of the wind tunnel to allow the rising smoke to be introduced into the flow stream. Drill a 1/4 to1/2 inch hole at the point where you wish to introduce smoke.
Properly set up your wind tunnel including the item that you wish to test. Make sure everything is properly secured, so it will not come loose during the experiment.
Insert a smoke bomb into the coffee can and set it off. Quickly place the coffee can, open side up, underneath the smoke hole, allowing the smoke to be sucked into the wind tunnel and flow across the model.
If you wish, you can get two coffee cans and rest the wind tunnel on these, so you do not have to hold the source of the smoke. Be certain the wind tunnel is stable and will not rock or fall.
Set up the Tunnel
Tips and warnings
- You can try a lit cigarette inserted into the smoke hole, but be warned that your wind tunnel will smell like cigarette smoke. If you wish to try this, secure the cigarette in place with tape or putty.
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