| A | B |
|---|
| weather | the short-term state of the atmosphere, including temperature, humidity, precipitation, and visibility |
| humidity | the amount of water vapor in the air |
| water cycle | the continuous movement of water |
| relative humidity | the ratio of the amount of water vapor in the air to the maximum amount of water vapor the air can hold at a set temperature |
| condensation | the change of state from a gas to a liquid |
| dew point | the temperature at which a gas condenses to a liquid |
| cloud | a collection of small water droplets or ice crystals suspended in the air |
| precipitation | any form of water that falls to the Earth's surface from the clouds |
| air mass | a large body of air where temperature and moisture content are constant throughout |
| front | the boundary between air masses of different densities and usually different temperatures |
| thunderstorm | a usually brief, heavy storm that consists of rain, strong winds, lightning and thunder |
| lightning | an electric discharge that takes place between two oppositely charged surfaces |
| thunder | the sound caused by the rapid expansion of air along an electrical strike |
| tornado | a destructive, rotating column of air that has very high wind speeds |
| hurricane | a severe storm that develops over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low pressure storm center |
| thermometer | an instrument that measures and indicates temperature |
| barometer | an instrument that measures atmospheric pressure |
| windsock | an instrument to determine wind direction |
| wind vane | an instrument to determine wind direcrtion |
| anemometer | an instrument used to measure wind speed |
| isobars | lines that connect areas of equal air pressure |
