Water Cycle

Evaporation Liquid water gains heat and turns into water vapor.

Condensation Water vapor loses heat and turns into liquid water.

Precipitation Water falling from the sky.

Transpiration The process of emitting water vapor through the leaves of plants .

Weather Factor #4: Water Water in the atmosphere vapor clouds

Humidity Measure of the amount of water vapor in the air. Amount depends on the air temperature. Warm air can hold more water vapor.

Relative Humidity Percent of water vapor that is actually in the air compared to the maximum amount it can hold at a particular temperature.

Tool to measure relative humidity Sling Psychrometer

Relative Humidity Example at 10 degrees Celsius 1 cubic meter of air can hold 8 grams of water vapor; if there were 8g of vapor in the air then the relative humidity would be 100%. What would the relative humidity be if the same cubic meter of air had 4 g of water vapor? 50 %

Relative humidity is 25%, how many grams of water? 2 g at 10 degrees Celsius 1 cubic meter of air can hold 8 grams of water vapor; if there were 8g of vapor in the air then the relative humidity would be 100%. Relative humidity is 25%, how many grams of water? 2 g

What happens if the temperature of the air increases? Warm air can hold more water

Why might condensation occur if air is cooled enough? The amount of water in the air would become greater than the air could hold.

Dew Point The temperature at which condensation begins. Must have surface to condense on. Dew point below 0 degrees C Frost

Condensation forms clouds. Tiny particles in the atmosphere provide surface for water vapor to condensate on. Dust Salt Smoke

Clouds Stratus- flat layered clouds, spread out usually cover the sky. Low level clouds.

Cumulus Fluffy rounded piles of cotton. Low level clouds.

Cirrus Wispy, feathery clouds. High level clouds.

Add-ons Alto- high Nimbo/Nimbus- rain Altostratus Altocumulus Nimbostratus Cumulonimbus

Precipitation Rain. Sleet- as rain falls through air that is below 0 C it freezes. Freezing rain- rain freezes as it hits cold surface. Snow- vapor converted directly to ice crystals. Hail- ice pellets, updrafts push it back into the cumulonimbus cloud where it grows.

Cloud Seeding Silver oxide Dry ice