Evaporation, Condensation, and

Precipitation

The States of WaterEvaporation And

Humidity States of water

• Solid (ice)• Liquid (water)• Gas (vapor)

With the person next to you…

…write down as many places that you can think of in the environment that contain water.

In what ways do these transition from one form to another?

EvaporationEvaporation

water molecules with enough energy to escape the water's surface

a cooling process

Humidity a measure of the amount of moisture in

the air specific humidity-the amount of water

vapor actually present in the air when specific humidity = air's capacity

for holding water vapor air is saturated

HumidityRelative

humidity expressed as a % amount of water in

the air / how much it could hold

How Does Condensation Happen?

Air Temperature Reaches the Dew Point Dew Point - temperature at which saturation

occurs 4 Ways that air loses heat

• contacting a colder surface• radiating heat• mixing with colder air• expanding when rises

How Does Condensation Happen?

Water needs to condense on something

• condensation nuclei Salt sulfate or nitrate particles (pollution)

• puff of smoke contains millions of particles

F/A 18 forces condensation out of the air approaching the speed of sound

Clouds Clouds

high fogs, mist, or haze that form when air above the surface cools below its dew point

Three main cloud types Cirrus

• thin feathery or tufted high ice-crystal clouds

Stratus• low sheets or layers, form in stable

air (moving upward slowly) Cumulus

• thick fleecy masses formed by vertically rising air currents

Cloud Types Clouds are classified into a system that uses

Latin words to describe the appearance of clouds as seen by an observer on the ground.

Latin Root Translation Examplecumulus heap cumulusStratus layer altostratus cirrus curl of hair cirrus nimbus raincumulonimbus

Types of Clouds

Forms of Precipitation

Rain – liquid from stratus / cumulus clouds Hail – frozen clumps of ice crystals from

cumulonimbus

Sleet – raindrops that freeze on their way down

Snow – solid particles from stratus / cumulus clouds

Hail

Where it Rains…

Pacific Northwest

Precipitation Areas

Where it Rains windward side of mountain ranges storm areas, places where air rises and cools areas favored by global wind belts

• where air converges and has to go up…. around the Equator

Where it Doesn’t leeward side of mountain ranges areas of sinking (warming) air high pressure areas where global wind belts diverge

Denver

Acid Rain

Sulfate (SO2) and Nitrate (NO2)particles from pollution act as condensation nuclei

from burning of fossil fuels, volcanoes, and automobiles

Effects of Acid Rain

Avalanche Lake in Adirondack Park, New York State. Watersheds are especially vulnerable to acid rain

Vermont's maple trees are particularly susceptible to the effects of acid rain