1. Water in the Atmosphere 18.1

2. Precipitation Any form of water that falls from a cloud.

3. Latent Heat The energy absorbed or released during a change in state.

4. Evaporation The process of converting a liquid to a gas.

5. Condensation The change of state from a gas to a liquid.

6. Sublimation The conversion of a solid directly to a gas without passing through the liquid state.

7. Deposition The process by which an agent of erosion loses energy and drops the sediment it is carrying; also the process by which water vapor is changed directly to a solid without passing through the liquid state.

8. Humidity A general term referring to water vapor in the air but not to liquid droplets of fog, cloud, or rain.

9. Saturated The state of air that contains the maximum quantity of water vapor that it can hold at any given temperature and pressure.

10. Relative Humidity The ratio of the air’s water-vapor content to its water-vapor capacity.

11. Dew Point The temperature to which air has to be cooled in order to reach saturation.

12. Hygrometer An instrument designed to measure relative humidity.

13. Key Concept When it comes to understanding atmospheric processes, water vapor is the most important gas in the atmosphere.

14. Key Concept The process of changing state requires that energy is transferred in the form of heat.

15. Key Concept When saturated, warm air contains more water vapor than saturated cold air.