| A | B |
|---|
| water cycle | the continous movement of water from water sources into the air, onto land, into and over the ground, and back to the water sources |
| humidity | the amount of water vapor or moisture in the air |
| relative humidity | the amount of moisture the air contains compared with the maximum amount in can hold at a particular temperature |
| condensation | the change of state from a gas to a liquid |
| dew point | the temperature to which air must cool to be completely saturated |
| cloud | a collection of millions of tiny water droplets or ice crystals |
| precipitation | solid or liquid water that falls from th air to the Earth |
| air mass | a large body of air that has similar temperature and moisture throughout |
| front | the boundary that forms between two difrferent air masses |
| thunderstorm | small, intense weather systems that produce strong winds, heavy rain, lightning, and thunder |
| weather | the condition of the atmosphere at a particular time and place |
| lightning | the large electrical discharge that occurs between two oppositely charged surfaces |
| thunder | the sound that results from the rapid expansion of air along a lightning strike |
| tornado | a small, rotating column of air that has high wind speeds and low central pressure and that touches the ground |
| hurricane | a large, rotating tropical weather system with wind speeds of at least 119 km/h |
| thermometer | a tool used to measure air temperature |
| barometer | an instrument used to measure air pressure |
| windsock | a devise used to measure wind direction |
| wind vane | a device used to measure wind direction |
| anemometer | a devise used to measure wind speed |
| isobars | lines that connect points of equal air pressure |
