Bernoulli's Principle

If a bird is in a tree and decides to go explore somewhere else, it takes off and elegantly flies away. However, if we did the same thing we wouldn’t fly. We would fall straight to the ground! Birds have specially designed wings that help them accomplish flight, something that our bodies are not able to do. With these wings and help from the Bernoulli Principle, we can see how they work! The Bernoulli Principle states that as air moves around an object it creates different pressures on that object. Faster air means less pressure and slower air means more pressure.  Bird wings are curved.Due to this curvature, the air that passes over the top of the wing needs to move faster. As Bernoulli states, faster moving air will cause less air pressure. The slower moving air on the bottom side of the wing will cause more air pressure. If there is more air pressure pushing up from below the wing, the bird gets lifted up and it can fly away! Do you want to see Bernoulli’s principle in action? Try this easy experiment at home!

Materials: Paper, scissors.

Directions: Cut the paper into two stripes. First, make a prediction. What do you think will happen when you blow between two pieces of paper?  Now, try it! Take a piece of paper in each hand, holding the short edge, and hold them up to your mouth. Each piece of paper should be at the edge of your mouth. Blow between the two pieces of paper. Did what you expect to see happen?

How It Works: Bernoulli’s principle taught us that fast air has less pressure on an object. By blowing air between the two pieces of paper, you decreased the amount of pressure and the air on the outside of the paper was able to push it inwards!

Want more? Research it! How do airplanes stay in the air when they’re flying?