ch.5.less.5.how do weathering and erosion shape the land
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How do weathering
and erosion shape the
land?
UNIT C:
CHAPTER 5: LESSON 5:
Weathering
The process in which rocks or other materials are broken down.
Different types of weathering:
Physical weathering Chemical weathering
Physical Weathering:
Physical weathering is caused by:
1) Temperature changes
(Causes rocks to crack)
2) Plant roots growing in rocks breaking the rocks.
3) Water freezing in cracks between rocks cause the
rocks to break apart.
4) Rubbing
5) Animals making burrows.
Chemical Weathering:
Occurs when chemicals break down the rocks.
1) Water dissolves rocks.
The agents of chemical weathering:
2) Acid Rain
Formed when gases from factories combine with rain water.
Erosion
The process by which water, ice, wind or gravity moves
fragments of rock and soil.
If a particle is loosened by
weathering, but stays put, its
just weathering.
If it starts moving, its Erosion.
Water Erosion
Rivers, streams, and runoff
Ice Erosion
Glaciers
Wind Erosion
Mass Movements
Landslides, mudslides, slump and creep
Get out a piece of paper and identify if the following involve
weathering, erosion, both, or neither.
Ready?
1.Waves are crashing on a sand beach.
2.Water expands as it freezes in the cracks of rocks.
3. Pebbles move down a stream with the current.
4. Acid rain causes the decomposition of a statue in New York.
5. A man shovels dirt to plant a tree.
6. A Glacier slowly moves down a mountain.
7. A tree’s roots grow into the cracks of rocks.
8. A major volcano erupts.
9. A boy takes out the
garbage for his mother.
10. A shovel is left outside
and begins to rust.
Once you’ve answered these,
discuss you’re answers with the
rest of the class before you go
on.
Let’s Discuss The Questions.
1. As the sand is moving there is
definitely erosion; there is also
abrasion from the sand gains
colliding. Both
2. This is frost wedging so it’s
mechanical weathering.
There is no mention of
movement. Weathering
3. There is probably some
weathering, but there is
definitely erosion. Erosion or
Both
4. Acid rain on a statue is
chemical weathering. This is
mainly Weathering.
5. Since the man is
transporting Earth materials,
it’s Erosion.
6. A glacier moving down a
mountain would have both
weathering and erosion.
Both
7. A tree’s roots growing into
cracks of rocks would be
weathering. Weathering
8. A major volcanic eruption
would involve both
weathering and erosion.
Both
9. Unless the garbage has
“Earth Material” or dirt in it
there is probably no erosion
or weathering. Neither
10. The rusting of a shovel is
oxidation. This is chemical
weathering. Weathering
The process by which materials are
dropped off at another place is called:
Deposition
Erosion and
deposition work
together to change
the shape of the
earth’s surface.
Ways that erosion and deposition work together:
1) Running water
Slow moving water Deposition
Fast moving water Erosion
2) Waves
Headland
Land surrounded by
water from 3 sides.
When waves reach a headland they
curve around it and wash away at
the sides of the headland.
3) Wind
Wind erodes sand and rock, when the
wind slows down the sand and rock get
deposited.
How can people protect shorelines?
Shorelines may be damaged when more sand is
eroded than deposited.
People can protect shorelines by:
1) Building dams (to change the speed and direction
of water)
2) Building levees (prevent floods)
3) Building barricades (prevent beach erosion)
4) Building fences (prevent sand erosion by wind)
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