| A | B |
|---|
| atmosphere | layer of gases that surrounds the earth |
| troposphere | bottom layer of the atmosphere, extending from ground level up to about 16 kilometers above the earth |
| stratosphere | second layer of the atmosphere; includes the ozone layer |
| mesosphere | third layer of the atmosphere, the coldest layer |
| thermosphere | outermost layer of the atmosphere; includes most of the ionosphere |
| ionosphere | layer of the atmosphere containing ions, or electrically charged particles |
| evaporate | change from a liquid to a gas |
| water vapor | water in the form of a gas |
| condense | change from a gas to a liquid |
| altitude | height above the earth's surface |
| stratus cloud | low, flat cloud that forms in layers |
| precipitation | moisture that falls to the earth from the atmosphere |
| fog | stratus cloud that forms near the ground |
| cumulus cloud | puffy, white cloud occurring at medium altitudes |
| cirrus cloud | high, wispy cloud made of ice crystals |
