Flight

Things that fly need air. Even though we walk through it, breathe it, and sneeze it, air seems to be a whole bunch of nothing. But air is there, and it’s powerful. Balloons inflate because air presses on the insides and outsides of the balloon. Air pressure in tires supports the weight of bikes, buses, trucks, cars, and planes. But air doesn’t need to be inside something to exert pressure. Air that moves around pushes, too.

What do birds, planes, kites, Frisbees, and helicopters have in common? They fly because moving air creates lift, or a push up. Airplane wings are shaped to push air down. The momentum of the air going down pushes wings up. Air above the wing gets going faster than the air underneath. Fast-moving air zips along, without pushing as hard side to side or up and down. The slow air pushes up from below harder than the fast air pushes down from above… and you’re airborne!

Every flying thing, from the tiniest flying insect to the biggest airplane, uses momentum and these differences in air pressure to fly. The pressure force is called the Bernoulli Effect, named after the scientist who discovered it. Without it, we’d be grounded.

So don’t miss the “Flight” show — where Bill Nye takes you up, up, and awaaaay.

The Big Ideas

• Air has pressure.
• Moving air creates differences in air pressure, which can be used to develop lift.

Did You Know That?

• Charles Lindberg was the first human to fly across the Atlantic Ocean? He had so many fuel tanks in his tiny plane that he used a periscope to see where he was going.
• Arctic terns have the longest migration? Every year, these birds fly 35,400 kilometers (22,000 miles) between the United States and Greenland.
• The fastest kite speed ever recorded was 193 kilometers (120 miles) per hour?

Books of Science!

• “What Makes Airplanes Fly?: History, Science and Applications of Aerodynamics”by Peter P. Wegner.Published by Springer-Verlas, 1991.
• “Look Inside Planes”by Michael Johnstone, illustrated by Hans Jenssen.Published by Dorling Kindersly, 1994.
• “Flight”by Kim Taylor.Published by John Wiley and Sons, Incorporated, 1992.