1. WATER IN THE ATMOSPHERE
Honors Earth science
Chapter 16

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

3. Water changes state Gas to solid? Deposition Frost Solid to gas?
Sublimation
Dry ice
Most water vapor enters atmosphere through
EVAPORATION

4. Latent heat
When changing phase; temp. remains steady

5. LATENT HEAT “Hidden heat” Released during condensation
Absorbed during evaporation

6. http://jamaica. u. arizona. edu/ic/nats1011/lectures/ch05/FIG05_006

7. Relative Humidity

8. Warm air can hold more water vapor than cold air!!

9. relative humidity Temp.= 31ºC water vapor in air= 25 g
Calculate the rh:
25/29.4= .85 x 100= 85%
85% of the air is filled with water vapor
What happens at 100% RH?
condensation!

11. How do we measure the amount of water vapor in the air?
Cool it until it can’t hold anymore moisture.
This temp is DEW POINT

12. Dew point Temperature at which 100% humidity occurs
(condensation temp)
Condensation (dew) will form if above freezing
Frost will form if below freezing
FROST IS NOT FROZEN DEW!

13. Who cares about dew point?

14. Lawn care Sports on grass Farmers/ Gardeners Bad hair days?
Tell the humidity
When air temp. is closer to dew point temp, humidity is higher

15. Today’s weather Grosse Pointe
Humidity: 58%
Dew Point:21°
Pressure: in
Visibility: 10.0 mi
UV Index: 0 - Low