Earth Science
Unit 1
Chapter 5
Lesson 1
Weathering and Erosion
Start-Up Work
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
Pick up a Supplemental
Packet from the Lab
Table by the door
Answer the following
questions in your packet
(pg 2):

Have you ever tripped over
a crack in the sidewalk?
Why are sidewalks
designed with spaces
between the sections and
why do they raise and
buckle?
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
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Objectives:
Identify and discuss
several processes of
mechanical weathering
Discuss the results of
basic mechanical
weathering processes
Observe the process and
effects of mechanical
weathering
Let’s see the results!
Class trip to the Freezer to retrieve straws
from yesterday!
 Answer the Questions:

 What
happened to the clay?
 What do you think will happen when the water
in the cracks of rocks freeze?
Weathering

Defined: breaking down of rocks into
smaller pieces by chemical or physical
processes
Mechanical Weathering

Aka Physical Weathering- the breaking
down of rocks by physical processes
 No
chemical processes are involved
Most is caused by temperature extremes
 Other causes include ice, water, and
activities of living things

Ice Wedging

When water in cracks of rocks expands, it
creates a bigger crack
Extreme Climates
Desert- changes in temperature causes
the surface layer of the rocks to fracture
from the under layers
 When this process occurs in granite or
other hard rocks it is called exfoliation

Water

Waves hitting a rock shoreline creates
steep cliffs called sea cliffs
Living Things
Trees can sink their roots into rocks
splitting them
 Animals- expose rocks to the processes

 Mollusks
can bore holes into rocks!
Bring it all together!
Answer the questions in your text books
on page 90.
 Write the answers in your supplemental
packet
 After completed- read lesson 2 if you do
not finish, it is homework!
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