Earth Notes - Lecture 3: Earths Modern Atmosphere...

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Earth’s Modern Atmosphere Atmosphere: The thin veil of gases surrounding Earth, which forms a protective boundary between outer space and the biosphere. It extends about 300 miles from the Earth’s surface. Above 300 miles is the exosphere : outer space Air Pressure: the weight of the atmosphere Gravity compresses air. Air pressure averages nearly 15 pounds per square inch at sea level. Air is denser (pressure is higher) at the surface than it is higher up. Why aren’t we crushed by air pressure? We have a counterbalancing force within us. Atmospheric pressure is measured in millibars Which are FALSE? A. Air pressure is defined as : the weight of the atmosphere. B. We are not crushed by air pressure because of a counterbalancing force within us, pressing out. C. Gravity compresses air, so air is denser at the surface than it is higher up. D. The air pressure is nearly 200 pounds per square inch at sea level. E. Atmospheric pressure is measured in millibars here in the U.S. F. Above 300 miles is the exosphere; below that is the earth’s atmosphere G. The higher up, the more molecules there are in the air, and more oxygen you get with each breath. Falling through Space In 1961, Kittinger went up 19.5 miles and jumped out of a helium filled balloon. Why was the sky black? Because there weren’t any air molecules to reflect the light. Why didn’t he hear anything? Because there wasn’t enough air to produce sound. Why didn’t his air suit flutter in the wind? Because there wasn’t enough air to create friction. Which is FALSE about Kittinger’s jump from space? A. Although it was daytime, the sky was almost black, because there were no air molecules to reflect the light. B. There was a huge rushing noise as he hurtled through space. C. His air suit didn’t flutter, because there wasn’t enough air to create friction Composition of the Atmosphere: 78% : Nitrogen 21%: Oxygen .04%: Carbon dioxide Which answer contains three of the most important elements/molecules in the atmosphere? A. Nitrogen, oxygen, helium
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This note was uploaded on 04/04/2011 for the course ASTR 1101 taught by Professor Mcgimsey during the Spring '11 term at Georgia State University, Atlanta.

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Earth Notes - Lecture 3: Earths Modern Atmosphere...

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