| A | B |
|---|
| weather | condition of the Earth's atmosphere |
| atmosphere | layerof gases that surround the planet |
| ozone | contains three oxygen atoms instead of the usual two |
| water vapor | water in the form of gas |
| pollutants | harmful substances in the air |
| photochemical smog | brown haze that forms in cities |
| acid rain | rain that contains more acid than normal |
| density | amount of mass in a given volume of air |
| pressure | force pushing on an area or surface |
| air pressure | force caused by air pressing down |
| barometer | measures changes in air pressure |
| mercury barometer | open glass tube partially filled with mercury |
| aneroid barometer | uses such as in an airplan instrument panel |
| altitude | elevation; height above sea level |
| troposphere | layer of the atmosphere where Earth's weather occurs |
| stratosphere | contains the ozone layer that absosrbs ultraviolet radiation |
| mesosphere | protects the Earth's surface from being hit by meteoroids |
| thermosphere | outer most layer of the atmosphere |
| ionosphere | the lower layer of the thermosphere |
| exosphere | outer layer of the thermosphere |
| aurora borealis | also called the "Northern Lights" |
