Download Hydrologic Cycle Note

The Hydrologic Cycle
- Water is essential to all life on Earth, it covers 75% of the earth’s
surface and 80% of the human body is made of water.
The Hydrologic Cycle: - Serves to distribute water over the
earth.
- Aids in the process of water
filtration/purification.
-The hydrologic cycle begins in the oceans
Evaporation: Water is changed from liquid to a vapour when heated. Water
leaves behind salts and other impurities as it evaporates. As the
evaporated moisture rises, it declines in temperature at the average rate of
1°C/100m. Moving air masses carry the vapour over the land.
Condensation: Water vapour is changed to a liquid (or solid). A critical
temperature called “dewpoint” is reached and the heat absorbed to change
from liquid to vapour is lost. At this point liquid water droplets must form
around a nucleus particle such as dust, smog or other air pollutant.
Precipitation: Liquid water falls to the earth in many forms including rain,
hail or snow. It may re-evaporate while falling.
Interception: Water which lands on tree leaves, other plant leaves such as
grass and does NOT enter the ground. This water usually evaporates.
Transpiration: Water, in a vapour state, contributed to the atmosphere by
the exhalation (breathing) of plants and animals.
Precipitaion May:
a) Evaporate back into the atmosphere
b) Soak into the soil (INFILTRATION)
c) Travel downhill back into a body of water (RUNOFF)
Moisture May:
a) Return to the surface of soil (CAPPILLARY ACTION) and evaporate
b) Continue to move underground into underground streams.
c) Continue moving through underground streams into water bodies.
Surface Moisture May:
a) Evaporate to the atmosphere
b) Ultimately reach the ocean