Earth ScienceUnit 1

Chapter 5Lesson 1Weathering and Erosion

Start-Up Work

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?

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 processesNo 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 processesMollusks 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!