Transcript The Water Cycle

Homework
The Water Cycle
 Continuous
process by
which water
moves through
the living and
nonliving parts
of the
environment.
Sun
 provides
ENERGY to
power the water
cycle in the form
of HEAT
Water on the Earth


Chemical Formula: H2O
71% of the surface of
earth is water.
 97% is salt water
 3% is fresh water
 76% is frozen in the
ice caps at the poles
**NON-CONSUMABLE!**
23% is groundwater
 ≤ 1% lakes, rivers,
water vapor

Evaporation
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
Most important process in the water cycle
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!

Transpiration

Plants absorb water from the soil
t
and
it moves from the roots
through the stems to the leaves.
From 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.

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Where would you have more
moisture (water vapor)….desert
or forest? Why?
Condensation
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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
The warm air on the outside of the glass
comes in contact with or near the cold
glass. The warm air cools off and
changes to a liquid
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.
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.
Surface Runoff


MOST precipitation
runs off the surface
and flows downhill
into streams.
These flow into
larger streams, then
rivers, and
eventually flow back
into the ocean.
Infiltration


Rain water
soaks/seeps/infiltrates
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.
Percolation

Percolation happens AFTER
the water infiltrates/seeps
into the ground, it flows
and is stored there, thus
becoming ground water
Take Notes
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Title to the left.
Text to the right.
Write what is in
yellow.
Groundwater
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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, then percolates 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 (amount of space
between soil particles/rocks) of
the rock (like pores on
your skin)
Aquifer

An underground bed
or layer of permeable
rock, sediment, or soil
that yields water.

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Unconfined: groundwater is
in direct contact with the
atmosphere through the
open pore spaces of the
overlying soil or rock
Confined: permeable rock
units that are usually deep
underground and are under
relatively impermeable rock
or clay that limits
groundwater movement
into, or out of it
Water Table


the level below
which the ground is
saturated with
water.
The “line” at the top
of an UNCONFINED
aquifer
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When you start
digging in a field
(fairly deep) and you
start to see water,
you are at the water
table
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.
.
Conclusion: Earth’s Water Supply
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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!
Earth’s Water Lab
Aquifer Video
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https://www.youtube.com/watch?v=NWCj
2wlMDsQ
https://www.youtube.com/watch?v=oNW
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Water Distribution