Access Prior Knowledge
Lesson 3: What is weathering?
Opening Activity
Open Science textbook to page 272.
Open Science workbook to page 89A to review home learning.
Open Science folder to review vocabulary words and outline for the chapter.
Open Science journal and answer the following questions:
1. What evidence do we see on the Earth's surface that plates are moving?
Review Content Cards and Q-Cards in bin, sharing with partners quizzing each other quietly.
Log in to clickers using student ID number.
Be ready to review home learning when timer goes off.
Don't forget to write your home
learning in your agenda page 90A.
Do you agree with the statement?
1
Yes
No
Weathering is an explosive force that
blows rocks apart.
Do you agree with the statement?
2
Yes
No
Gravity and ice can cause mechanical
weathering.
Do you agree with the statement?
3
Yes
No
Chemical weathering occurs faster in
deserts than in rainforests.
Do you agree with the statement?
4
Yes
No
Weathering helps to make the mixture of
sediments that make up soil.
Mechanical Weathering
When rocks break into smaller pieces (sediments) by forces due to gravity, ice, plant roots or
other forces is mechanical weathering.
Water can get into cracks of rocks and when it freezes it expands splitting the rock (ice
wedging).
Plant roots can grow into cracks of rocks and after time can break the rock into sediments.
The rate of mechanical weathering depends on the materials in a rock and the conditions around
it.
First paragraph
pg. 272
Second paragraph
pg. 272
Chemical Weathering
When there is changing of materials in a rock by chemical process is chemical
weathering.
Rain can cause chemical weathering because it can be made of carbonic acid
dissolving parts of the rock forming caves where stalactites form because of
dripping water.
Areas with a lot of rain will have a lot of chemical weathering.
Fungi and other organisms can also give off chemicals that can change rocks.
Some rocks are affected by chemical weathering faster than others, for example
soft limestone weathers more quickly than hard granite.
First paragraph
pg. 274
Weathering
Soil
There are three types of soil that are made up of a mixture of sediment, decayed material, gases from air and water.
Topsoil- has a large amount of decayed material from plants, animals, bacteria and other organisms.
Subsoil- contains many minerals but only a little bit of decayed materials.
Bedrock- nearly solid rock that lies underneath the surface that will eventually become soil sediment.
Third paragraph
pg. 274
Soil
MatchQuest
Mechanical Weathering
Forces
Ice wedging
Chemical Weathering
Plant roots
Chemicals
Gravity
TextQuest
1. Do hard or soft stones show the most weathering?
2. In which soil layer are the most decayed materials found?
3. Describe how soil is made.
4. Compare and contrast mechanical and chemical weathering?
5. What are two ways mechanical weathering changes rocks?
Don't forget to write your home
learning in your agenda page 90A.