1itexpands itexpandsbecausepressureislower 2itcools

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Unformatted text preview: altitude there is less air pressing downward and air pressure is less 8 Effects of air movement Basic Properties of Air: What happens when air rises to higher altitudes? 1. It expands It expands because pressure is lower 2. It Cools It cools because expansion leads to cooling (PV = nRT) Example: Air coming out of a tire is cool 9 Effects of air movement Basic Properties of Air: 3. It may rain. Cold air can hold less water than warm air: So water (in rising air) may condense and fall. 1+2+3. Rising air rain or snow: When warm air rises, it expands, cools off and can not hold as much water vapor…so it rains/ snows 10 Effects of air movement Example of how air movement affects climate: Rain shadow Wet green side Very dry brown side Basic Properties of Air: 11 Rain shadow Air rises, expands and cools. Result: rain on windward side Moist air Wind Evaporation Dryer air blows to leeward side, sinks and warms up. Result: dry warm area, called a rain shadow. windward side: Wet Leeward side Dry 12 Rain shadow 13 Field Trip Big Island­­Hawaii 14 15 16 17 18 Class question Which side of the island gets 128 inches, and which side gets 10 inches, of rain a year? Why? Explain the large difference. Important: The wind comes off the Pacific Ocean from the East 19 20 Example 2: Atmospheric convection (mixing) Effects of air movement 2) Rising air expands, cools, relative humidity rises until condensation of water vapour occurs above condensation level. Basic Properties of Air: Condensation level 1) Air warms by contact with warm ground...
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This note was uploaded on 03/23/2010 for the course ISP 217 taught by Professor Peacor during the Spring '08 term at Michigan State University.

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