Transcript What are the processes that cause the Earth’s surface to

1. What are the processes that
cause the Earth’s surface to wear
down?
1. Physical weathering
2. Chemical weathering
3. erosion
2. What is the most frequent
cause of rocks breaking apart?
1. Water freezing and thawing in rock
cracks.
Water expands when it freezes and enlarges
the cracks. This causes the rock to
eventually break apart.
3. How do plants wear down rocks?
1. Roots grow into cracks and
then grow larger, making
the racks larger. (physical
weathering)
4. What is an example of
oxidation?
• Rusty nail or rocks containing
iron undergo oxidation and
breakdown.
5. Where does carbonic acid
come from?
• Water and carbon dioxide
combine in the air or below
the earth’s surface
6. What does carbonic acid do to
certain kinds of rocks?
• Carbonic acid can dissolve
some types of rocks.
7. What type of rock do you
suppose is most easily broken
down by carbonic acid?
• Limestone – acid causes it
to fizz
8. What are lichens, and how do
they break down rocks?
• Small crusty organisms algae
and fungus
• Secrete a mild acid that breaks
down the rocks (chemical
weathering)
9. What natural forces cause
erosion?
• Water, wind, ice, and gravity
10. What is mass movement?
• Water seeps into earth,
causing land and rocks to
separate and slide, resulting
in landslides and rockslides.
11. How and where does water
cause erosion?
• Water can pick up and wash
away rocks and earth materials,
especially in places like the
Grand Canyon and along
coastlines.
• The faster the water flows or
the more water = more erosion.
12. How does wind cause
erosion?
• Tiny grains of sand are
picked up and carried by the
wind. Sand hitting soil and
rocks breaks more particles
loosen.
13. How does ice cause erosion?
• Glaciers push earth
materials along as they
move downhill.
14. Wind blowing across bare soil
moves earth material. Which size
particle do you think the wind would
carry farther and which would it deposit
first?
• The smallest, lightest particles =
carried farther
• Larger, heavier particles =
deposited first when the wind
slows down.
15. Explain the steps in breaking down
mountain rocks and depositing sand, silt
and clay in different places hundreds of
miles away.
1. Weathering breaks the rock into smaller and
smaller pieces until they form sand, silt or
clay.
2. Wind or water carry these materials.
EROSION
3. Wind or water slows down, heavier particles
are deposited first. Lighter particles go
farther.
16. If you could visit the Grand
Canyon about a million years
from now, what changes in the
canyon would you expect to see?
• More erosion and weathering
• The Grand Canyon would probably be
wider and deeper.