Water Cycle
Precipitation
• After condensation occurs (forming clouds), water droplets fall in various forms of precipitation – 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.
• Gravity is the driving force for precipitation.
Evaporation/Transpiration
• Water enters the atmosphere as water vapor through the processes of evaporation and transpiration (i.e. plants releasing water vapor).
• Thermal energy from the sun causes water to evaporate and/or transpire.
Condensation/Crystallization
• As water vapor rises in the atmosphere it can turn into water droplets or ice crystals which results in cloud formation.
• Condensation of water vapor into water droplets or ice crystals must occur on a surface.
* In the atmosphere, dust particles (or any other particulates) serve as a surface for water to condense on.
• These processes can form on Earth’s surface in the following forms:
* 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 are at the freezing point or below.
• Increases in thermal temperature causes water vapor to rise (evaporation) while a decrease in thermal temperature triggers condensation (clouds, dew, and frost).
Downhill Flow of Water on Land
• 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 space in the soil to hold the water.
• Gravity is the driving force for downhill flow of water on land.
Precipitation
• After condensation occurs (forming clouds), water droplets fall in various forms of precipitation – 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.
• Gravity is the driving force for precipitation.
Evaporation/Transpiration
• Water enters the atmosphere as water vapor through the processes of evaporation and transpiration (i.e. plants releasing water vapor).
• Thermal energy from the sun causes water to evaporate and/or transpire.
Condensation/Crystallization
• As water vapor rises in the atmosphere it can turn into water droplets or ice crystals which results in cloud formation.
• Condensation of water vapor into water droplets or ice crystals must occur on a surface.
* In the atmosphere, dust particles (or any other particulates) serve as a surface for water to condense on.
• These processes can form on Earth’s surface in the following forms:
* 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 are at the freezing point or below.
• Increases in thermal temperature causes water vapor to rise (evaporation) while a decrease in thermal temperature triggers condensation (clouds, dew, and frost).
Downhill Flow of Water on Land
• 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 space in the soil to hold the water.
• Gravity is the driving force for downhill flow of water on land.
