1. Water in the Air 3/17/15 16-1a pgs. 422-425 IN: Diagram the water cycle. How does temperature affect each phase?

2. TERMS AND OBJECTIVES TERMS: Weatherwater cyclehumidityrelative humidity condensationdew pointcloud precipitation OBJECTIVES: Explain how water moves through the water cycle Define relative humidity Explain what the dew point is and its relation to condensation.

3. The Water Cycle

4. Weather - the condition of the atmosphere at a particular time and place.

5. Humidity - the amount of water vapor or moisture in the air.

6. As temperature increases, the air’s ability to hold water also increases.

7. When there is more water in the air, you hair absorbs moisture and becomes longer.

8. Relative Humidity The amount of moisture the air contains compared with the maximum amount it can hold at a particular temperature.

9. Water Vapor Versus Temperature The more water vapor that is in the air at a particular temperature, the higher the relative humidity is.

10. Measuring Relative Humidity A psychrometer is an instrument used to measure the relative humidity.

11. The difference in temperature readings between the wet-bulb and dry-bulb thermometers indicates the amount of water vapor in the air.

12. Dry-Bulb Temperature = 20 o CDifference = 10.8 o C

13. Condensation - the process by which a gas becomes a liquid.

14. Condensation and Humidity In order for condensation to occur, the air must be saturated. It must have a relative humidity of 100%.

15. Dew Point - the temperature to which air must cool to be completely saturated. Water vapor can condense and form small water droplets called dew.

16. OUT: If the relative humidity reaches 100%, what happens?