Water cycle and precipitation

1. Water cycle and precipitation

2. Water Cycle 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

3. Water Cycle · Condensationhappens in the atmosphere as water vapor changes to water droplets. · Clouds form as a result of condensation. · Dewforms when water vapor condenses directly onto a surface; · Frostforms 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.

4. Water Cycle Run-off · If precipitation falls on land surfaces, it always attempts to move back toward sea level as surface-water flowor groundwater flow. · The surface that receives the precipitation determines its flow back towards sea level.

5. 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.

6. MENU Precipitation _____________ · 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. Water Cycle Animation

7. Precipitation • ________-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

8. Precipitation • 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

9. Freezing Rain Continued… • 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

10. MENU Precipitation • 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.

11. Precipitation • 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 _________

12. Hail Continued… • 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!

13. Precipitation • 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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