External Processes

Erosion Weathering

Table of ContentsDate Title Lesson #

8/27 5 Themes of Geography 2

8/28 The 5 A’s 3

8/31 Geographer’s Tools 4

9/1 Internal Forces 5

9/3 External Forces 6

1. Draw a line underneath wherever you left off yesterday.

2. Write the title “External Forces”

• Weathering - forces that are changing rocks, land, and objects over time, even day to day.

• 2 types: Mechanical Weathering and Chemical Weathering

COPY WHAT’S IN THE BOX

Mechanical weathering – a force breaks a rock into smaller pieces by forcing them apart.

- Example: Breaking large rocks into smaller ones

COPY WHAT’S IN THE BOX

Causes of Mechanical Weathering

1. Root wedging – roots break up rocks

2. Frost Wedging - ice get into rocks

3. Thermal expansion – heat causes rocks to expand and break

COPY WHAT’S IN THE BOX

Effects of Mechanical Weathering

Conclusion

• How is mechanical weathering like a hammer?

• Directions: Copy the sentence above and write one complete sentence responding to it in your notebook.

Chemical Weathering

• Chemical weathering - when something "eats away" at a rock instead of breaking it apart.

• Requires a chemical change in the rocks

COPY WHAT’S IN THE BOX

Causes of Chemical Weathering

1. Acid Rain

Directions:

- Copy the headline and each cause

-Under where you wrote Acid Rain, briefly explain each step of the Acid Rain process in your notebook.

Regions Sensitive to Acid RainOrso University Challenge Question: Why do Houston, Chicago, and Los Angeles have such low levels of acid rain?

Causes of Chemical Weathering

2. Water – creates a chemical reaction in certain objects

3. Chemicals – resulting from pollution or internal processes

Foaming pollution on rocks.

Effects of Chemical Weathering

At PH1, this New Zealand lake is pure hydrochloric acid

Naked trees

Rust

Analysis

- Create a weathering wonderland. - Sketch a landscape that includes examples

of weathering resulting from each of the 6 causes. (3 mechanical, 3 chemical)

- Label each cause

Rocks that have split apart due to thermal expansion.

Directions/Requirements

- Need 6 pictures (3 mechanical weathering and 3 chemical weathering)

- Need a caption explaining each cause

- Need a title

Weathering Wonderland Conclusion

You are the mayor of a new city called Weathering Wonderland.

1. How does weathering harm your city?

2. How can you be proactive in addressing the problems caused by weathering? - List and EXPLAIN three steps you will take to ensure that problems from weathering are minimized.

Closure

1. Answer the Question of the Day.