Water cycle and

precipitation

Evaporation/Transpiration

· Water enters the atmosphere as water vapor through evaporation and transpiration, plants releasing water vapor.

Humidity- the amount of water vapor in the air

Relative humidity- compares the amount of water in the air with the maximum amount of water vapor that can be present at that temperature

· Condensation happens in theatmosphere as water vapor changes to water droplets.· Clouds form as a result of condensation.· Dew forms when water vapor condenses directly onto a surface;· Frost forms when water vapor changes from gas directly to ice crystals on a surface when the temperature at which condensing would take place is at the freezing point or below.

Run-off

· If precipitation falls on land surfaces, it

always attempts to move back toward sea

level as surface-water flow or groundwater

flow.

· The surface that receives the precipitation

determines its flow back towards sea level.

Examples are:· Water will remain on the surface when the surface is not porous or the precipitation is falling too fast for the water to sink into the ground.· Water will sink into the ground when the surface is porous and there is lots of space in the soil to hold the water.

_____________· After condensation occurs (forming clouds), water droplets fall in various forms of precipitation

Exe: rain, snow, freezing rain, sleet, or hail, depending upon weather conditions.

· Temperature variations within clouds and/or within the region between the cloud and Earth allows for the various forms of precipitation. MENU

• ________- most common type of precipitation.• tiny cloud droplets

collide to form bigger droplets. 

• Droplet becomes too ______ for the air to support it. 

• Air is warm enough on the way down and on the surface for drops to remain liquid

• Freezing Rain- raindrops freeze as they hit the ground or other surface.• Occurs when there is a

layer of ___________ (warmer) air on top of a shallow layer of _________________

• When it hits the sub-freezing layer it will _________ but not freeze.

• Drops fall as liquid until they hit the cold air and freeze into ice as they land on a surface

• Since the surface temperature is below freezing, objects in constant contact with the air _______________

• Rain freezes when it comes into contact with these surfaces (exe: the ground)

• Major cause of “black ice” on highways during winter

• Sleet- raindrops that freeze ______ they hit the ground.

• Warm layer of air on top of a deep sub-freezing layer of air at the surface

• The above-freezing (warm) layer allows __________

• However, as the drops hit the cold layer, they will freeze and hit the ground as frozen water droplets.

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• Hail-Solid ice precipitation that occurs during intense thunderstorms

• Different from sleet• Cumulonimbus clouds

can get super tall to reach parts of the atmosphere that are _________

• Drops of water rise up due to ______________

• They collide and grow larger

• When they get high enough they _________

• Once the hailstone freezes,

• When it grows too large for the updrafts to keep it suspended, it falls to the ground• The stronger the

updrafts, the ______ the hailstones

• Can range from pea-sized to softball-sized!

• Snow- precipitation that is frozen

•     Occurs when the layer of the atmosphere from the cloud all the way to Earth’s surface is entirely below freezing. 

• The precipitation falls from the cloud as snow and does not melt at all while falling to the ground. 

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