| A | B |
|---|
| nitrogen | most abundant gas in the atmosphere |
| oxygen | makes up 21% of the atmosphere |
| water vapor | varies between 0-4% |
| brown smog | nitrogen oxides, unburned hydrocarbons, in presence of sunlight |
| gray smog | sulfur oxides from coal or oil burning |
| ozone | a pollutant at ground level, a natural sunscreen in the stratosphere |
| solids in the atmosphere | dust, salt, and ice |
| troposphere | weather, clouds, and smog occur in this layer |
| thermosphere | contains the ionosphere and the exosphere |
| ionosphere | layer of electrically charged particles, radio waves reflected |
| exosphere | contains few air molecules or ions |
| air pressure | force exerted on an area due to the mass of air above it |
| stratosphere | gets warmer as alititude increases; contains natural ozone layer |
| mesosphere | gets colder as altitude increases |
| ultraviolet radiation | one of the higher frequency radiation forms given off by the sun |
| chlorofluorocarbons (CFC's) | chemicals thought to destroy ozone molecules |
| radiation | transfer of energy by electromagnetic waves |
| conduction | transfer of energy by direct contact with heated substances |
| convection | transfer of heat by the flow of heated material |
| water cycle | pathway water moves between land, ocean, and atmosphere |
| hydrosphere | all the water on the Earth's surface |
| evaporation | change from liquid to vapor state |
| condensation | change from vapor to liquid state |
| precipitation | moisture that falls from clouds |
| pressure differences | caused by uneven heating of the Earth's surface |
| Coriolis effect | deflection of all free-moving objects due to Earth's rotation |
| doldrums | zone of warm, rising air at the equator |
| prevailing westerlies | blow from 30-60 degrees north and south |
| tradewinds | blow from east to west near the equator |
| polar easterlies | blow from 60-90 degrees north and south |
| jet streams | narrow belts of high altitude winds that blow from west to east |
| sea breezes | created during the day |
| land breezes | movement of air toward the water at night |
| valley wind | upslope breeze blows in early morning |
| mountain wind | cool air at mountain top sinks into valley after sunset |
| monsoon wind | moist, ocean air blows in over land creating heavy rains in summer |
