| A | B |
|---|
| weather | the condition of Earth's atmosphere at a particular time & place |
| atmosphere | The layer of gases that surrounds Earth |
| ozone | a form of oxygen with 3 atoms instead of 2, which is the MAJOR CHEMICAL found in smog |
| water vapor | water in the form of gas |
| air pollution | a change to the atmosphere that has harmful effects |
| emissions | particles & gases that are released into the air |
| greenhouse effect | the trapping of heat near Earth's surface by water vapor, carbon dioxide & certain other gases in the atmosphere |
| global warming | the theory that the increase in carbon dioxide in the atmosphere will cause Earth's average temperature to continue to rise |
| air pressure | the result of the weight of a column of air pushing down on an area |
| altitude | the distance above sea level (elevation above sea level) |
| barometer | any instrument that measures changes in air pressure |
| pressure | the amount of force pushing on an area |
| mercury barometer | instrument that measures changes in air pressure using liquid mercury |
| aneroid barometer | instrument that measures changes in air pressure without using a liquid |
| density | the amount of mass in a unit volume of a substance |
| troposphere | the lowest layer of the atmosphere where weather occurs |
| stratosphere | second-lowest layer of Earth's atmosphere (contains ozone) |
| exosphere | outer layer of the thermosphere |
| mesophere | the middle layer of the atmosphere where most meteroids burn up |
| thermosphere | the outermost layer of the Earth's atmosphere (is divided into 2 layers) |
| ionosphere | the lower part of the thermosphere (where electrically charged particles called ions are found) |
| photochemical smog | a thick brownish haze formed when certain gases in the air react with sunlight |
| 78% | the amount of nitrogen in the atmosphere |
| 21% | the amount of oxygen in the atmosphere |
| 1% | the amount of gases other than nitrogen & oxygen that are in the atmosphere |
| ozone layer | a layer of the upper atmosphere that protects people from the effects of too much ultraviolet radiation |
