1. Evaporation, Condensation, Clouds and Precipitation

2. Water exists as a solid, liquid, and gas
can change from one state to another
The change from a solid to a liquid is called melting, liquid to a solid is called freezing
Heat of Fusion = +/- 334 J/g/°C

3. GAS LIQUID SOLID

4. Evaporation the process of water changing from a liquid to a gas
occurs when water absorbs energy from its surroundings
Because of this, evaporation results in the surroundings becoming cooler (think of sweating)
Heat of Vaporization = 2260 J/g

6. EVAPORATION IS A COOLING PROCESS

7. Condensation the process of water changing from a gas to a liquid
occurs when water vapor loses energy
Because of this, condensation results in the surroundings getting warmer
Heat of Vaporization = J/g

8. COOL TEMPS - CONDENSATION
WARM TEMPERATURE - EVAPORATION

9. CONDENSATION IS A WARMING PROCESS

10. Clouds formed by the condensation of water vapor
There are three main types of clouds: cumulus, stratus, and cirrus
Cumulus clouds are thick, puffy clouds. They tend to be lower in the sky
Stratus clouds appear as low to middle sheets or layers of clouds
Cirrus clouds appear as high, thin or “feathery” clouds. These clouds are made of ice crystals
There are many forms of these types of clouds
Ex. Cumulonimbus clouds often produce strong thunderstorms and can form tornadoes!!
Nimbus – rain/storm in Latin

12. CLOUDS have FLAT BOTTOMS which indicate the level of the atmosphere where the dew point temperature has been reached!

13. Cumulus clouds are "fair weather" clouds and are unlikely to produce precipitation
They form in warm air on sunny days
Cumulus clouds can form at almost any altitude, with bases sometimes as high as 14,000 feet

14. Cumulus clouds are clouds of vertical development and may grow upwards dramatically under certain circumstances
The updrafts may be caused by heating of the air by the ground surface, the action of a cold front, or to temperature differences between land and ocean
The vertical air currents results in towering clouds with an anvil head on top called cumulonimbus clouds

16. Stratus clouds are low clouds, ranging in height from near the earth's surface up to 6,500 feet
Stratus clouds form flat layers or uniform sheets
Only a fine drizzle can form from stratus clouds because there is no vertical development

19. Cirrus clouds are wispy in appearance, and resemble horsetails (they are sometimes called mares' tails)
They are among the highest clouds, forming at elevations of 25,000 feet and above, where the temperatures are far below freezing
Cirrus clouds are formed almost entirely of tiny ice crystals

21. Precipitation
any form of water that falls from the clouds when they become too large be supported by the air
Forms of precipitation include:
Rain
Snow
Sleet – rain that falls through air that is below freezing
Freezing rain – rain that freezes on contact with a surface that is below freezing
Hail – formed in cumulonimbus clouds (thunderstorms). These are ice balls which can be as large as a softball!! HAIL USUALLY HAPPENS IN THE SUMMERTIME!!
**When water condenses on nitrate and sulfate particles (from burning fossil fuels), acid rain is formed

25. Hail Formation

28. Supercooled Rain Level
Snow Level
Ice Level
Supercooled Rain Level
BRRRR…I’m CHILLY!
Rain Level

32. Precipitation does not occur the same everywhere (OROGRAPHIC LIFT)
Wind hits the windward side of the mountain, rises, cools off, and condensation happens
This forms clouds and precipitation
As the air goes over the top, is sinks on the leeward side
As the air sinks, it compresses together and gets warmed by friction
Since the warmer air can hold more moisture, condensation does not occur (and no precipitation)!
Occurs along the Sierra Nevada Mts. The California side is wet, the Nevada side is dry