1. Do you like hiking? Have you ever hiked Guadalupe Peak in West Texas? Its elevation is 8,749 feet. It is the highest point in Texas. It is actually getting shorter each year. What could cause Guadalupe Peak to shrink? There are three forces that work together to literally “move mountains”—weathering, erosion, and deposition.
2. What are weathering, erosion, and deposition? How do they work together to move mountains? “Weathering” is breaking down rocks through physical or chemical means. “Erosion” is moving sediment. “Deposition” is using the sediment to make new landforms.
3. Physical weathering occurs when rocks are broken down by force. It is also called “mechanical weathering.” What are some forces that could break down rocks? Imagine rocks falling on other rocks and cracking them. Think of when water freezes in cracks in rocks, making the cracks bigger. Other types of physical weathering include animals’ stepping on rocks, winds’ blowing sand against rocks, animals’ digging near rocks, and plants’ growing by rocks. Can you think of other ways that physical weathering might happen?
4. Chemical weathering also happens on Guadalupe Peak. Chemical weathering takes place when rocks are broken down by chemical reactions. What are some chemical reactions that can break down rocks? Water reacts with minerals in rocks. Acid rain causes chemical weathering. Chemicals from plants can cause chemical weathering. How else might chemical weathering occur on Guadalupe Peak?
5. “Erosion” is another part of moving mountains. After rock has been weathered, erosion moves the sediment to another place. How might sediment be moved off of Guadalupe Peak? Running water carries sediment. Glaciers transport sediment. Wind picks up sediment and moves it. Gravity moves large amounts of sediment through events such as landslides, mudslides, and rock falls.
6. What happens to sediment after it moves off of Guadalupe Peak? After sediment has been weathered and eroded, it does not disappear; it is deposited. Deposition occurs when sediment settles out. For example, wind blows sediment off of Guadalupe Peak into a nearby river. The river moves quickly enough to keep the sediment moving until it comes to a lake and slows way down. Then the sediment settles to the bottom of the lake and is deposited. Now a small part of Guadalupe Peak is at the bottom of a lake!
7. Can you imagine a sign on top of Guadalupe Peak that says “Guadalupe Peak—7,988 feet above sea level”? Weathering and erosion are currently working on Guadalupe Peak. They are doing the same thing to rocks and minerals all over the world. The forces of weathering, erosion, and deposition make it possible to move mountains, such as Guadalupe Peak, piece by tiny piece.
###Assessment
QUESTION 1
The term “weathering” in paragraph 2 means:
OPTIONS
Mechanics
Break down
Transport
Settle out
QUESTION 2
How does the passage explain moving a mountain?
OPTIONS
Using technology to move mountains
Earthquakes and volcanic eruptions
Weathering, erosion, and deposition
None of the above
QUESTION 3
What is the difference between physical and chemcial weathering?
OPTIONS
Physical weathering only happens with plants and animals, while chemcial weathering is caused by technology.
Physical weathering is breaking up rocks by force, while chemcial weathering involves chemical processes.
Physical weathering is what you observe, and chemcial weathering is invisible.
Physical weathering and chemcial weathering are the same thing.
QUESTION 4
Which is an example of chemical weathering?
OPTIONS
Acid rain falling on rocks
Chemicals from plants on rocks
Water reacting with minerals in rocks
All of the above
QUESTION 5
What is the main point of the passage?
OPTIONS
Weathering breaks up rocks and moves them to other places over time.
Guadalupe Peak will get shorter as time passes.
Weathering, erosion, and deposition work together to break down rocks, move sediment, and let sediment settle out and build new landforms.
Without weathering and erosion, Earth would have no mountains.
QUESTION 1
The term “weathering” in paragraph 2 means:
Break down
QUESTION 2
How does the passage explain moving a mountain?
Weathering, erosion, and deposition
QUESTION 3
What is the difference between physical and chemical weathering?
Physical weathering is breaking up rocks by force, while chemical weathering involves chemical processes.
QUESTION 4
Which is an example of chemical weathering?
All of the above
QUESTION 5
What is the main point of the passage?
Weathering, erosion, and deposition work together to break down rocks, move sediment, and let sediment settle out and build new landforms.