Transcript changing earth and oceans powerpoint

Changing
Earth And
Oceans
1. Earth’s lands and oceans can be affected
by NATURAL PROCESSES, or events
that occur naturally in the environment.
Some of these processes occur
SLOWLY while others are rapid
processes. We can also classify these
processes according to whether they are
created from CONSTRUCTIVE or
destructive forces.
2. The natural processes we
will be concerned with in this
unit are: WEATHERING,
erosion, DEPOSITION,
landslides, volcanic eruptions,
EARTHQUAKES, and floods.
3. Classifying the natural processes that
affect Earth’s lands and oceans:
RAPID
SLOW
LANDSLIDES
WEATHERING
VOLCANIC
ERUPTIONS
EARTHQUAKES
EROSION
FLOODS
DEPOSITION
CONSTRUCTIVE
DESTRUCTIVE
DEPOSITION
WEATHERING
VOLCANIC
ERUPTIONS
FLOODS
EROSION
LANDSLIDES
EARTHQUAKES
FLOODS
4. Destructive forces are
those that DESTROY
landforms. They change
the surface of the earth by
WEARING IT DOWN.
5. Weathering is the process where rocks
and minerals near the surface of the
earth are BROKEN DOWN, dissolved,
or decomposed into smaller pieces. It
can SMOOTH the edges of rocks and
wear down the peaks of mountains. It
can also be affected by:
a. HARDNESS of the rocks (what it is
made of)
b. SLOPE of the land
c. Exposure to sun and RAIN / WATER
d. Climate or TEMPERATURE
6. Weathering can be
considered
PHYSICAL (a.k.a.
mechanical) or
chemical.
7. Physical (MECHANICAL)
weathering only changes the
SIZE / SHAPE of the rock. It
does not change the rock’s
composition, or WHAT IT IS
MADE OF. It can be caused
by three things:
a. Temperature change- rocks EXPAND in
the summer and contract in the winter
b. Frost wedging (a.k.a. frost ACTION)when rainwater gets into a crack, the
water FREEZES. When it freezes, it
EXPANDS and breaks the rock.
c. PLANT roots- they break right through
the rock.
8. Chemical weathering
changes the SIZE of the
rock BUT ALSO changes
the rock’s
COMPOSITION. It can
be caused by two things:
a. The air we breathe- water and air change
iron into RUST [called iron oxide=
oxygen (O2) + iron (Fe)]
b. CARBONIC acid dissolves the rockwhen CO2 in the air dissolves with
rainwater/groundwater, it forms a weak
acid called carbonic acid (a.k.a.
carbonated water)
9. Caves and caverns are formed when
rocks dissolve forming hollow areas.
•
stalactites- hang from the CEILING
•
Stalagmites- up from the GROUND
c. columns- where they both MEET
d. They are formed from rock made mostly
of calcite or LIMESTONE, which is
easily worn away by carbonic acid.
Stalactite
Column
Stalagmite
10. Erosion- the process of
CARRYING away (or
transporting) weathered
materials like rocks,
minerals, and soil. These
materials are carried away
by WIND, water, and
gravity.
11. Agents of erosion
are the FORCES
that carry out erosion.
Common agents of
erosion include:
a. Water- the most
COMMON. It
carries materials such
as soil, sand, and
pebbles.
• Water breaks,
ROUNDS, and
polishes rocks
• The distance water
carries rocks depends
upon the SIZE of the
particles and the
FORCE of the water.
• It forms a “V”
shaped valley
between mountain
peaks.
• Can form DELTAS
when it drops the
sediment because it is
unable to CARRY it
anymore.
• WAVES AND
TIDES also
erode the land
• The GRAND CANYON
is an example of a
landform being created
from water erosion, thanks
to the COLORADO River
over many years.
b. Glaciersmoving masses
of ICE
• As gravity pulls ice
DOWN the mountain,
rocks and soil are
pushed, DRAGGED,
or carried with it.
• They form a “U”
shaped valley from
the original “V”
shaped one.
• As they melt, they
DROP the rocks and
soil they were
carrying at one time
(called its LOAD).
• They actually formed
the GREAT LAKES
(remember “Homes”)
c. Gravity- eroded
materials tend to
move to LOWER
elevations because
gravity pulls them
DOWN
d. Wind- the
WEAKEST
agent
• It is only moving air and
can only pick up SMALL
particles of rock and
topsoil. Obviously, it it’s a
stronger amount of wind,
more materials can be
picked up.
e. Human activitywe can
INCREASE the
speed of
destructive forces
• Cutting down
TREES- roots can’t
keep the soil in place
and increases
erosion. So roots
help reduce erosion.
• Air pollution from
factories and CARS
increase weathering.
• MINING or digging
into the land
12. Landslides- SUDDEN mass
movements of land downhill
due to gravity
• They can cause
BUILDINGS to fall or power
lines and gas lines to break
• They can even occur on the
continental slope in the ocean
13. Earthquakes-
VIBRATIONS on the
Earth’s surface caused
by a sudden movement
or release of ENERGY
in Earth.
a) They are often found along
a FAULT, or a break in the
Earth’s surface
b) Some cause little
DAMAGE and some
cause LOTS of damage
c) Large
EARTHQUAKES
can cause
landslides
d) When they occur under the
ocean, huge waves are
created (called
TSUNAMIS) and can
destroy land and cause
great damage if the waves
come ashore.
e) SEISMOGRAPH is an
instrument that measures
vibrations inside the earth.
By observing these
vibrations, scientists may
be able to predict when
they occur
f) When inside during an
earthquake, get under a
STURDY table. Avoid
being near windows
because they may
shatter.
g) If outside, quickly move
to an OPEN SPACE
and avoid trees, power
lines, or buildings that
could fall on you.
h) Be prepared! Make
a SURVIVAL kit
(water, batteries,
flashlight) and
practice (drills).
i) Scientists are now
investigating ways to
make buildings
earthquake-PROOF
14. Floods- occur when
LARGE amounts of
water cover land that
is usually DRY.
a) Heavy RAIN or
quickly melting snow
can cause water to
flow OVER the land
(flood).
b) When the flood
occurs, rapid
EROSION can take
place and move soil
and sediments away.
c) When the flood
RECEDES (goes back),
new sediment is left behind
and can BUILD up rich
soil deposits.
15. Constructive forces are
those that CREATE
landforms. They BUILD
UP the Earth’s surface.
These forces include
DEPOSITION, volcanic
eruptions, and floods.
16. Deposition- the
dropping (or
DEPOSITING) of
sediments by water,
wind, or ice.
a) It BUILDS UP new land
on the surface of the earth,
like a DELTA at the end of
a river or a pile of sand
(sand DUNE) in the
desert. It also builds up
beaches and river banks.
b) SHELLS on the
beach are evidence
of deposition by
ocean waves.
17. Volcanic
eruptions can
change the
Earth’s surface:
a) Volcanoes are
MOUNTAINS with
openings in the Earth’s
crust where magma,
gases, and ash reach the
surface
b) When magma reaches the
surface it is called LAVA. As
the lava eventually cools, new
land (mountain) is created.
The HAWAIIAN Islands are
examples of how volcanic
eruptions have created new
land.
c) When the magma erupts
from the volcano, the top of
the mountain can be
changed.
d) Lava and ASH can
destroy forests and bury
fields.
e) Volcanic eruptions can
even change weather
patterns.
f) When volcanic mountains
are formed under water,
they are called
SEAMOUNTS.
g) The RING OF
FIRE is the area
where most
volcanic activity
occurs.
18. The ocean has
many geologic
landforms.
a) Continental shelf- where the
edges of the continent slope
own from the SHORE into
the ocean. It is the part of the
continent located UNDER
the water. Abundant fishing is
found on the shelf.
b) Continental slope- where
the shelf drops to the
BOTTOM of the ocean
floor. The depth of the
ocean water increases
greatly here.
c) Mid Ocean Ridge- an
underwater volcanic
MOUNTAIN range on the
bottom of the ocean which
divides the ocean floor into
two parts.
North America
Africa
South America
d) Rift zone- a
TRENCH in the
center of the highest
part of the mid-ocean
ridge.
e) trenches- steep-sided
CANYONS and deep,
narrow valleys in the bottom
of the ocean. They are the
deepest part of the ocean
basin and are deeper than
any valley on land.
f) Ocean basin- located on
either side of the mid-ocean
ridge. It is made up of low
HILLS and flat PLAINS and
are the deepest part of the
ocean. It is also known as
the ocean FLOOR, abyssal
plain, and ocean plain.
19. Earth is made of SOLID land.
Some of the land is located
above the Earth’s water and
some is located below the
oceans. Even so, there are
similarities and differences
between landforms found in
these two areas:
Continental Landforms
(above water)
Oceanic Landforms
(below water)
CANYON
TRENCHES
VALLEY
RIFT ZONE
VOLCANO
SEAMOUNT
MOUNTAIN RANGE
MID-OCEAN RIDGE
LOW HILLS OR
PLAINS
OCEAN BASIN AND
PLAINS
Labeling ocean
floor adobe file
20. The area where
the ocean meets the
land is called the
OCEAN SHORE
ZONE.
a. It has specific
features that can be
affected by WAVES,
currents, tides, and
storms (like
hurricanes).
b. BEACHES, barrier
islands, estuaries, and
inlets are all affected by
natural processes like
those mentioned above.
21. Beaches- the
sandy area on the
coast (or shoreline)
where the land meets
the ocean.
a. They are
changing because
of WIND AND
WATER.
b. WAVES can wear
away the land and
expose a rocky shore.
They can also deposit
SAND along the shore,
forming a beach.
c. If the waves reach
the beach at an
ANGLE, the sand is
moved along the coast.
d. Currents (called
LONGSHORE
currents) along the
shoreline can move
sand from one location
to another.
e. TIDES can bring in
sand, shells, and ocean
sediments at high tide
and leave them behind
at low tide.
22. Barrier Islandswith sandy beaches
that are
SURROUNDED by
water on all sides.
a. They occur naturally
and help PROTECT
the mainland from the
effects of waves on its
shore.
b. As waves deposit
SAND on the beaches,
the shape of the barrier
islands change.
c. CURRENTS can
move sand from one
end of the island to
another.
23. Estuaries- the area
where a RIVER meets
the ocean They have a
mixture of FRESH
AND SALT water.
a. WAVES can deposit
sand in the estuaries.
b. At high TIDE ocean
water brings in sediments
and sea life that feed and
provide nourishment for
the estuary.
24. Inlet- water-filled
spaces BETWEEN
barrier islands.
a.As the tides change, the
amount of WATER in the
inlet will change.
b.Ocean currents and
STORMS can change
the shape of an inlet
opening.
25. Water on Earth
can be moved in
various ways:
a. WAVES- the repeated
movement of water.
•Its highest part is
called the CREST and
lowest part is called
the TROUGH.
• Most are caused by
WINDS that blow across
the water’s surface.
• They can change their
shape when they reach
the shore.
•Tsunamis are
examples of giant
TIDAL waves caused
by underwater
EARTHQUAKES.
b. Currents- FLOWING
streams of water that move
continually through the
ocean in a specific direction.
They can be on the
SURFACE of the ocean or
deep in the ocean.
• Surface currents flow at
the top due to the force
and direction of the
WIND and the Earth’s
movement. They flow
along CURVED paths.
•Warm surface currents
are driven by the
Earth’s rotation from
TROPICAL to higher
latitudes.
•Cold surface currents
are driven by the
Earth’s rotation from
the POLAR latitudes
toward the equator.
c. TIDES- the rise and
fall of waters in oceans
and seas which
change the LEVEL of
water at the shoreline.
• They are caused by the
pull of the Moon’s
GRAVITY on Earth.
• High (FLOOD) tides
occur when the water
level is at its highest
point.
•Low (EBB) tides occur
when the water level is
at its lowest point.
•Tides rise and fall
about TWICE a day
(about every 6 hours).
• Neap tides occur when the
sun and moon are pulling on
the Earth at RIGHT angles.
The result is that there is
LITTLE difference between
high and low tides.
• SPRING tides occur when
the sun and moon are IN
LINE with the Earth. We
get higher high tides and
lower low tides at this time.
26. Human activities can
HELP the land and ocean
preserve the resources that
these areas provide. The
wise use of natural
resources is called
CONSERVATION.
a. The 3 R’s: REDUCE
(use less of), reuse
(use again), and
RECYCLE (make a
new product from old
materials).
b. Clean-up projects
(litter pick-up, Beach
Sweep).
c. Putting up fences or
wind BREAKS to
prevent erosion
d. Creating JETTIES along
beaches to keep sand from
washing away.
e. Planting TREES, bushes,
and grass to improve air
quality and keep erosion
from carrying away the soil.
f. Crop
ROTATION
(changing crops from
year to year).
g. COMPOSTING
27. Human activities can also
HARM the land and oceans
by causing resources to be
DAMAGED or destroyed.
Pollution is anything that
HARMS the natural
environment.
a.Dumping materials into
RIVERS (which eventually
flow into estuaries and
oceans)
b. LITTER pollutes land and
water.
c. Landfills for our TRASH
can leak into groundwater
d. SMOKE from cars, factory
fumes, and burning fuels
pollutes the air (acid RAIN,
smog).
e. OIL SPILLS harm
the ocean and can
cause life there to be
killed.