|
 water cycle | the constant movement of water |
| evaporation | the process of becoming a vapor |
| precipitation | the falling to earth of any form of water (rain or snow or hail or sleet or mist) |
| ground water | underground water that is held in the soil |
| front | the boundary between two different air masses |
| land breeze | breeze at night flowing from the land to the sea |
| sea breeze | breeze flowing during the day from the sea to the land |
| hygrometer | Measures humidity |
| anemometer | instrument used to measure wind speed |
| barometer | an instrument used to measure air pressure |
| troposphere | the layer closest to Earth, where almost all weather occurs; the thinnest layer |
| wind | air moving (sometimes with considerable force) from an area of high pressure to an area of low pressure |
| westerlies | prevailing winds that blow from west to east in the United States |
| prevailing winds | the global winds that blow constantly from the same direction |
| greenhouse effect | warming that results when solar radiation is trapped by the atmosphere |
| El Nino | a short term climate change that occurs every two to ten years |
| climate | the average weather conditions in an area over a long period of time |
| weather | the condition of Earth's atmosphere at a particular time and place |
| cirrus | Wispy, feathery clouds made of ice crystals that form at high levels- usually mean fair weather or a change in weather |
| cumulus | Thick, fluffy clouds with flat bases, formed by vertically rising air currents- usually mean fair weather |
| cumulonimbus | A type of cumulus cloud that is tall and gray, and associated with thunderstorms. |
| stratus | Clouds that form in flat layers and often cover much of the sky- usually mean rain or snow |
| high pressure | A mass of sinking cool air that usually bring fair weather. |
| low pressure | A mass of rising warm air that usually bring wet, stormy weather. |
| warm front | a front where warm air moves over cold air and brings drizzly rain and then are followed by warm and clear weather |
| cold front | Forms when a cold air mass pushes a warm air mass;thunderheads can form followed by cool, fair weather. |
| wind vane | Instrument used to measure wind direction |
| condensation | the process by which molecules of water vapor in the air become liquid water |
| run-off | Water (usually from rain) that flows over a land surface in streams and water ways |