
Overview
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, us
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1 - 1Flight September 10, 1993
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1 - 2Earth's Crust September 17, 1993
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1 - 3Dinosaurs September 24, 1993
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1 - 4Skin October 01, 1993
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1 - 5Buoyancy October 08, 1993
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1 - 6Gravity October 15, 1993
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1 - 7Digestion October 22, 1993
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1 - 8Phases of Matter October 29, 1993
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1 - 9Biodiversity November 05, 1993
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1 - 10Simple Machines November 12, 1993
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1 - 11The Moon November 19, 1993
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1 - 12Sound November 26, 1993
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1 - 13Garbage December 03, 1993
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1 - 14Structures December 10, 1993
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1 - 15Earth's Seasons December 17, 1993
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1 - 16Light & Color December 24, 1993
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1 - 17Cells January 21, 1994
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1 - 18Electricity January 28, 1994
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1 - 19Outer Space February 04, 1994
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1 - 20Eyeball February 11, 1994