water in the atmosphere. h 2 o exists in atmosphere in all three states of matter…
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Water in the Atmosphere
H2O exists in atmosphere in all three states
of matter…
Solid:
snow
hail
ice
Liquid: rain and
cloud droplets
Gas:invisible H2O
vapor
H2O may change
from one state to another:
Melting:•from solid ice to liquid H2O
Freezing:
•liquid H2O to solid ice
Evaporation: •from liquid H2O to H2O vapor
Condensation: from H2O vapor to liquid H2O
Sublimation: change from solid to H2O vapor
Example: Dry ice
Water vapor enters the atmosphere from the evaporation of water from oceans, lakes,
marshes and glaciers
Dew point: the temperature at
which water vapor condenses
•Dew, clouds, and fog forms
•If dew point is below freezing, frost will form
Warmer the air, the more H2O vapor it can
hold•Humidity:
water vapor in the air
• Relative humidity:the % of moisture the air can hold relative to the amount it can hold at a certain temperature
Relative humidity=specific humidity X 100
capacity (saturated)
Psychrometer: instruments used to measure relative
humidity• Works on principle
that evaporation causes cooling
• 2 thermometers…wet-bulb and dry-bulb
• Readings show how dry the air is
Clouds: simply high fogs, mist,
or haze•Form when air above surface cools below dew point
•Shape depends on air movement that forms it
-horizontal air movement = layers-vertical air movement = piles
• Temperature above freezing – clouds drop water
• Temperature below freezing – clouds drop snow crystals
Precipitation:•Water that falls from the
atmosphere to the earth•Occurs when cloud droplets
grow into drops heavy enough to fall to Earth
Acid precipitation: acid drops that fall to the
ground- contain nitrate and
sulfate particles that come from burning fuels, volcanoes and cars
• Cloud seeding: method to cause an increase in precipitation
Condensation nuclei: suspended particles that provide the
necessary surfaces for cloud forming condensation.
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