Lesson 9.1: Weathering
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Printed: October 15, 2013
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C ONCEPT
Concept 1. Lesson 9.1: Weathering
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Lesson 9.1: Weathering
Key Concepts
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Definition of weathering
Mechanical weathering
Chemical weathering
Rates of weathering
Lesson Objectives
• Define mechanical and chemical weathering.
• Discuss agents of weathering.
• Give examples of each type of weathering.
Lesson Vocabulary
abrasion: form of mechanical weathering that occurs when rocks and rock particles scrape against other rocks
chemical weathering: type of weathering that changes the mineral composition of rocks
erosion: transport of weathered material by water, wind, ice, or gravity
ice wedging: form of mechanical weather that occurs when water enters a crack in rock, expands as it freezes,
and wedges the rock apart
• mechanical weathering: type of weathering that breaks rocks into smaller pieces without changing their
mineral composition
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Teaching Strategies
Introducing the Lesson
Use the PowerPoint slide presentation at the URL below to introduce students to weathering. The slides alternately
present and answer basic questions about the topic. In addition to introducing lesson content, the questions will
allow you to assess what students already know before they start studying the chapter. You can revisit the slides at
the end of the lesson as a quick review of lesson content.
http://www.science-class.net/Warm_Ups/Warm_up_Erosion.ppt
Activity
Have students play the weathering and erosion game at the following URL. In the game, they will explore how
different agents of erosion change the landscape and the time spans they take to bring about observable changes.
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http://www.kineticcity.com/mindgames/warper/
Building Science Skills
Set up one or more of the stations described in the PDF documents below. At each station, students will investigate
a different aspect of weathering, including weathering by wind (station 1), dissolving rock (station 3), mechanical
weathering (station 4), and/or chemical weathering (station 5). The last URL below is a student handout that contains
background information and answer sheets for all of the stations.
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http://www.science-class.net/Lessons/Geology/Weathering_Erosion/WandE_1.pdf
http://www.science-class.net/Lessons/Geology/Weathering_Erosion/WandE_3.pdf
http://www.science-class.net/Lessons/Geology/Weathering_Erosion/WandE_4.pdf
http://www.science-class.net/Lessons/Geology/Weathering_Erosion/WandE_5.pdf
http://www.science-class.net/Lessons/Geology/Weathering_Erosion/WandEBackground%20Information.pdf
Differentiated Instruction
Ask a pair or small group of students to add the word weathering to the word wall. On a large index card, they
should write the term and its definition. They should also include separate definitions of mechanical weathering and
chemical weathering, with examples of each type.
Enrichment
Ask a small group of students to use the following Web site to organize a class game of weathering-and-erosion
jeopardy. One of the students should act as the MC. The Web site includes questions and answers weighted by
difficulty with different amounts of money awarded for correct answers. Suggest that the students use play money
to reward players who answer questions correctly.
http://www.regentsearthscience.com/jeopardy/erosion/jeopardy.htm
Science Inquiry
In the inquiry activity at the URL below, students hypothesize the effects of water and dilute hydrochloric acid on
limestone. Then they devise an experiment to test their hypotheses. Relate the results of their experiments to the
acceleration of chemical weathering by acid rain.
http://www.science-class.net/Lessons/Geology/Weathering_Erosion/weathering_lab.pdf
Overcoming Misconceptions
Students often confuse the terms weathering and erosion and may consider them to mean essentially the same thing.
As a result, they often use the words interchangeably. Make sure your students know the difference between these
two related processes. Stress that weathering breaks down rock but does not involve transport of the sediments. The
latter is the work of erosion, which moves but does not break down rock. You can demonstrate the difference between
weathering and erosion with the excellent 5-minute activity “Erosion and Weathering in My Mouth” (activity # 20)
at the following URL.
http://www.colorado.edu/geolsci/courses/DEMOS/seicontribution/101_lowtech_earth_science%20demos.pdf
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Concept 1. Lesson 9.1: Weathering
Reinforce and Review
Lesson Worksheets
Copy and distribute the Lesson 9.1 worksheets in CK-12 Earth Science for Middle School Workbook. Ask students
to complete the worksheets alone or in pairs to reinforce lesson content.
Lesson Review Questions
Have students answer the Review Questions at the end of Lesson 9.1 in CK-12 Earth Science for Middle School.
The answer key can be found in the Resource tab above the Table of Contents.
Points to Consider
What types of surfaces other than rock are affected by weathering?
What might the surface of Earth look like if weathering did not occur?
Do you think that you would be alive today if water did not dissolve elements?
Would the same composition of rock weather the same way in three very different climates?
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