May the Force Be with You: Lift
Airplane wings create lift to help keep it in flight.Copyright Wikimedia Commons http://commons.wikimedia.org/wiki/File:Antonov_An-2_in_Vitebsk.jpg
Students revisit Bernoulli's principle (presented in lesson 1 of the Airplanes unit) and learn how engineers use this principle to design airplane wings. Airplane wings create lift by changing the pressure of the air around them. This is the first of four lessons exploring the four key forces in flight: lift, weight, thrust and drag.
With their understanding of Bernoulli's principle, engineers manipulate air pressure to create lift. They design wings so that the air moves faster over the top of the wings than under the wings. Since we know from Bernoulli's principle that faster moving air has less pressure, the air pushes more on the bottom of the wing than on the top of the wing. This difference in pressure causes the wing to rise; engineers call this lift. Before testing their wing designs on real airplanes, engineers experiment with variations in wing shapes in wind tunnels to see how they perform in moving air.
After this lesson, students should be able to:
- Describe how four key forces (lift, weight, thrust, drag) act on airplanes during flight.
- Explain Bernoulli's principle.
- Use Bernoulli's principle to explain what lift means with respect to airplanes.