Transcript Chapter 11 Fresh Water

Chapter 11 Fresh Water
11.1 The Water Cycle
• Identify how Earth’s water is distributed
among saltwater and freshwater sources.
• Describe how Earth’s water moves
through the water cycle.
Engage/Explore
• Have a student
•
•
describe a rainstorm.
Where does the water
come from that falls
as rain?
How does the water
get into the clouds?
Discover - Where Does the
Water Come From?
• Fill a glass with ice
•
cubes and water,
being careful not to
spill any water. Wait
5 minutes.
Observe the outside
of the glass and the
surface it was sitting
on.
Introduction - Notes
• Why is Earth called
•
•
the “water planet”?
From space, this is
the image that
astronauts see.
Oceans cover nearly
71 percent of Earth’s
surface.
I. Water on Earth - Demo
• Most of Earth’s water is 97% percent salt water
•
that is found in oceans.
Only 3% is fresh water.
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–
–
–
76% ice masses
.037% atmosphere (water vapor in a gaseous form.
Less than 1% is fresh water available for human use.
Some of the Earth’s fresh water is deep underground.
A. Oceans
• All Earth’s oceans are
connected to form a
single world ocean.
B. Ice - Artic and Antarctica
• Icebergs are formed
from frozen fresh
water.
C. Rivers and Lakes - St.
Lawrence Seaway to the Great
Lakes
D. Below Earth’s Surface
• Groundwater - water
•
that fills the cracks
and spaces in
underground soil and
rock layers .
Far more fresh water
is located
underground than in
all Earth’s rivers and
lakes.
II. The Water Cycle
• Water Cycle - the
•
continuous process
by which water moves
through the living and
nonliving parts of the
environment.
All the water on Earth
has been through the
water cycle.
II. The Water Cycle
• In the water cycle, water moves from
bodies of water, land, and living things on
Earth’s surface to the atmosphere and
back to Earth’s surface.
• The sun is the source of energy that drive
the water cycle.
• Prentice Hall video and activity
A. Water Evaporates
• Exploring the water cycle p. 363.
• Evaporation - the process by which
molecules at the surface of a liquid absorb
enough energy to change to the gaseous
state.
• Ocean water that evaporates isn’t salty
because the salt remains in the ocean.
Plants
• Plants take in water
•
•
by drawing in water
form the soil through
their roots.
Transpiration - water
given off through the
leaves as water
vapor.
Plants give off a large
amount of water.
B. Clouds Form
• Condensation - clouds
•
form when condensed
droplets of water clump
together around tiny dust
particles in the air,
forming clouds.
Water vapor condenses
when it travels up in the
air because the air is
colder. Cold air holds less
water vapor than warm
air, so some of the water
vapor condenses.
C. Water Falls as Precipitation
• Precipitation - water
that falls to Earth as
rain, snow, hail, or
sleet.
Precipitation occurs
when water droplets
in a cloud grow larger
and larger. They
become so heavy that
they fall to Earth.
• Most water falls in the ocean which may
stay there for many years.
• Some water falls on land & evaporates
immediately.
• Some water runs off into rivers and lakes.
• Some water trickles down into the ground.
• Precipitation is the source of all fresh
water on and below Earth’s surface.
• The water cycle renews the usable supply
of fresh water on Earth.
• The total amount of water on Earth has
remained fairly constant and balanced.
• Water cycle song - “Clementine”
Questions
• What are the three processes in the water
cycle?
• Answer: evaporation, condensation,
precipitation
• Which process begins the cycle?
• Answer: a cycle has no beginning and no
end. The water cycle is continuous.
How Do People Use Water?
Ch. 11.2 Icebergs - p. 376
• P. 376 in text
• Titanic movie clip
Icebergs
• Titanic movie clip
• Glaciers move over land
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•
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and when they hit water
they become an iceberg.
10,000 form every year
from Greenland.
Only about 10 percent of
an iceberg is visible.
90% of an iceberg lies
below the surface.
Iceberg
• The underwater part
•
is a hazard to ships
because it is often
much wider than the
visible part of the
iceberg.
The International Ice
Patrol is now set-up
to track icebergs.