1. WATER IN THE ATMOSPHERE
Earth Science
Chapter 24

3. What state of water are clouds?
LIQUID

4. Water changes state Liquid → Solid Solid → liquid
freezing
Solid → liquid
melting
Gas (water vapor)→ liquid
condensation
Liquid → gas
evaporation

5. H2O Phase Changes DO: obj. 7.01 WATER VAPOR (Gas) Absorbs Heat
Releases Heat
Releases Heat
Absorbs Heat
Releases Heat
ICE
(Solid)
WATER
(Liquid)
Absorbs Heat

6. Water changes state Most water vapor enters atmosphere through
Gas to solid?
Sublimation
Frost
Most water vapor enters atmosphere through
EVAPORATION

7. LATENT HEAT Hidden heat DURING A PHASE CHANGE
Released by atmosphere during condensation
Absorbed by atmosphere during evaporation

8. Latent Heat ABSORBED Latent Heat RELEASED Condensation (Gas to Liquid)
Evaporation
(Gas)
Precipitation
(Liquid)
Latent Heat
RELEASED
Lake St. Clair

9. HUMIDITY Humidity: Water Vapor Capacity
Amount of water vapor the air can hold increases with temperature
Water Vapor Capacity
Amount of water in the air dependent upon the temperature of the air.

10. MAXIMUM WATER VAPOR (SATURATED AIR)
Capacity at 15oC =
Capacity at 20oC =
Capacity at 25oC =
Capacity at 30oC =

12. mass of water vapor (specific humidity)
Relative humidity-
mass of water vapor (specific humidity)
mass of water vapor that air can hold (saturated)
Expressed as a %
Changes with temperature

13. MAXIMUM WATER VAPOR (SATURATED AIR)

14. relative humidity Temp.= 40ºF water vapor in air= 25 g RH=
25/50 (from graph)= .5 x 100= 50%
RH=50%
Half of the air is filled with water vapor

15. MAXIMUM WATER VAPOR (SATURATED AIR)

17. TODAY’s AGENDA Pick up Humidity Lab Take out Objectives
Go over finding Humidity
Conduct our Humidity Lab
GET YOUR COAT…we’re going outside!

18. How does Air becomes Saturated
Add water by evaporation. OR
Lower the temperature to it's dew point

19. Psychrometer
An instrument used to measure relative humidity.

20. DEW POINT Temperature to reach saturation Air is saturated= dew
If below freezing=frost