| A | B |
|---|
| evaporation | the slow changing of a liquid into a gas when particles vaporize at the earth's surface |
| humidity | a measurement of the water vapor in the air |
| condensation | the changing of a gas into a liquid as heat is removed |
| precipitation | water that falls from clouds to the ground in the form of rain, sleet, hail, or snow |
| surface run-off | the portion of precipitation that runs off the surface as opposed to soaking in |
| fog | water vapor in droplets forming in the atmosphere |
| transpiration | the loss of water vapor from plants, the evaporation of water from cells within the leaves and exiting through stomas |
| infiltration | the process of water soaking into the soil as opposed to its running off the surface |
| dew point | the temperature at which water vapor condenses |
| water cycle | the continuous movement of water between Earth's surface and the air |
| watershed | the region that contributes to a river or a river system |
| water table | the upper surface of the groundwater that lies between soil and tightly packed rocks |
| aquifer | an underground area of rock and soil filled with water that is squeezed between tightly packed layers of rock |
| reservoir | a natural or artificial lake that stores supplies of freshwater |
