1. Weather Water in the Atmosphere May 14, 2008

2. Precipitation Precipitation is any form of water that falls from a cloud. Water vapor is the source of all condensation and precipitation. When it comes to understanding atmospheric processes, water vapor is the most important gas in the atmosphere.

3. Changing State The process of changing state requires that energy is transferred in the form of heat. Latent heat is heat used to melt ice that does not produce a temperature change.

4. Water’s Changes of State

5. Humidity Humidity is the term for the amount of water vapor in the air. Saturation describes the state when the number of molecules evaporating equals the number of molecules condensing.

6. Relative Humidity Relative Humidity is a ratio of the air’s actual water vapor content compared with the amount of water vapor air can hold at that temperature.

8. Temperature and Relative Humidity When the water-vapor content of air remains constant, lowering air temperature causes an increase in relative humidity, and raising air temperature causes a decrease in relative humidity

9. Dew Point Dew point is the temperature to which a parcel of air would need to be cooled to reach saturation.

10. Assignment Read pg. 504-509 Complete 18-1 ws