Lift Off!

Here's a quick and easy experiment that will demonstrate one of the reasons why airplanes can fly. All you need is a sheet of paper, 8 1/2" x 11".

Hold the paper in both hands. Place your hands on the sides near the bottom, with your thumbs on one side of the paper and the other eight fingers on the back. Let the paper flop down away from you so that it covers your fingers. Bring the paper up to your mouth and blow gently across the top. Pay special attention to what happens just after you start to blow. What do you think the paper will do?

You might think that the paper would move down because of the force of the air. But instead you see it move upward! This happens because the air moving over the surface of the paper reduces the air pressure on the top of the paper. Then the paper moves toward the area of lower pressure. This difference in air pressure is very important in understanding how airplanes fly, as you'll see in the next experiment.