CN: Water Cycle

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CN Water Cycle
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Process

• Continuous process by which water moves through
  the living and nonliving parts of the environment.

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Sun

• The sun provides energy to power the water cycle
• Without it the water cycle would stop

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Section 1 The Active River
Chapter 11
Water Cycle
Click below to watch the Visual Concept.
Visual Concept
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Water on the Earth

• Chemical Formula H2O
• Almost all the water on Earth is salt water
  (97).
• The other 3 is fresh water
• 76 of thatis frozen in the ice caps at the
  poles.
• Much of the remaining is groundwater.

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Evaporation

• Most important process in the water cycle
• Happens when the SUN heats up the water in
  rivers, lakes, and oceans and turns it into a gas
  (vapor or steam) and it goes into the atmosphere.
• Most of the water vapor that evaporates into the
  air comes from the oceans. The salt does not get
  enough energy to become a gas, so it stays
  behind.
• So rain is always fresh water!

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Condensation

• 2nd most important process in the water cycle
• Dew is formed by condensation of water vapor
• Takes place in the atmosphere
• The stage where gas turns into a liquid

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Clouds

• Water vapor cools as it rises in the air. As it
  reaches the dew point, the water vapor will
  condense around dust particles and form clouds.

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Precipitation

• Condensed water vapor that gets heavy enough to
  fall to the ground as rain, snow, sleet, or hail.
• Most water molecules only spend about ten days in
  the air before falling back as precipitation.

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Surface Runoff

• Much of the precipitation runs off the surface
  and flows downhill into streams. These flow into
  larger streams, then rivers, and eventually flow
  back into the ocean.

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Infiltration

• Infiltration is an important process where rain
  water soaks into the ground, through the soil and
  underlying rock layers.
• Some of this water ultimately returns to the
  surface at springs or in low spots downhill.

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Percolation

• Percolation is when water after it rains seeps
  into the ground and is stored there, thus
  becoming ground water

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Groundwater

• Some precipitated water that does not flow into
  rivers, lakes, etc sinks into the ground
  (permeable) and eventually reaches a layer it
  cannot pass through (impermeable).
• Most of the fresh water that is not frozen is
  underground.

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Groundwater

• As the water infiltrates through the soil and
  rock layers, many of the impurities in the water
  are filtered out. This filtering process helps
  clean the water.

• The amount of groundwater stored is dependent on
  the porosity of the rock (like pores on your skin)

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Transpiration

• As plants absorb water from the soil, the water
  moves from the roots through the stems to the
  leaves.
• Once the water reaches the leaves, some of it
  evaporates from the leaves, adding to the amount
  of water vapor in the air.
• The greatest living movers of water are plants.
• Where would you have more moisture (water
  vapor).desert or forest? Why?

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Aquifer

• An underground bed or layer of permeable rock,
  sediment, or soil that yields water.
• Confined permeable rock units that are usually
  deep under the ground and are under relatively
  impermeable rock or clay that limits groundwater
  movement into, or out of it
• Unconfined groundwater is in direct contact with
  the atmosphere through the open pore spaces of
  the overlying soil or rock

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Water Table

• the level below which the ground is saturated
  with water.
• The line at the top of an UNCONFINED aquifer
• When you start digging in a field (fairly deep)
  and you start to see water, you are at the water
  table

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Artesian Well
a pumpless water source that uses pipes to allow
underground water that is under pressure to rise
to the surface. This type of well seems to defy
gravity because the pressure that builds up
between layers of rock gets relieved when the
water finds a path to the open air. In addition,
the water has been naturally filtered because it
passes through porous rock as it seeps into the
Earth to reach the aquifer, which is the
underground water source. For centuries, people
have drilled artesian wells to drink filtered
water that doesn't need to be manually or
mechanically hauled up from the depths.
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Conclusion Earths Water Supply

• The total amount of water on the Earth has not
  changed much since early in its history.
• The same water is cycled over and over.
• The water you drink at lunch was probably drunk
  by a dinosaur millions of years ago!

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Water Distribution