Guided Practice
Learn
In this guided practice lesson, we will apply our knowledge of rocks, minerals, erosion, and weathering to solve real-world problems. You will work through scenarios that scientists and geologists encounter when studying Earth's surface.
Key Concepts Review
- Rock Cycle: The continuous process of rock formation, breakdown, and reformation
- Weathering: The breaking down of rocks by physical or chemical processes
- Erosion: The movement of weathered materials from one place to another
- Deposition: When eroded materials settle in a new location
Examples
Work through these examples to see the concepts in action.
Example 1: Identifying Weathering Types
A rock cliff near the ocean shows cracks filled with salt crystals. What type of weathering is occurring?
Answer: Physical weathering caused by salt crystallization. When ocean water enters cracks and evaporates, salt crystals grow and expand the cracks.
Example 2: Tracing Erosion Patterns
A farmer notices that after heavy rain, topsoil from a hillside ends up in the creek at the bottom. Describe the erosion process.
Answer: Water erosion is carrying sediment downhill. The rain loosens soil particles, and gravity helps water transport them to lower elevations where they deposit in the creek.
✏️ Practice
Test your understanding with these practice questions.
Practice Questions
0/3 correctWhat is the scientific method's first step?
A hypothesis is:
Which is a property of matter?
Check Your Understanding
Test yourself with these review questions. Click on each question to reveal the answer.
1. What is the main difference between weathering and erosion?
Answer: Weathering is the breaking down of rocks in place, while erosion is the movement of those broken-down materials to a new location.
2. A tree root grows into a crack in a sidewalk and breaks it apart. What type of weathering is this?
Answer: Physical (mechanical) weathering caused by biological activity (root wedging).
3. Why do rocks in rivers often become smooth and rounded?
Answer: The rocks tumble against each other and against the riverbed as water moves them, gradually wearing away rough edges through abrasion.
4. What are the three main types of rocks in the rock cycle?
Answer: Igneous (formed from cooled magma/lava), sedimentary (formed from compressed sediments), and metamorphic (formed from heat and pressure on existing rocks).
5. How does freezing water contribute to weathering?
Answer: Water seeps into cracks in rocks. When it freezes, it expands by about 9%, pushing the rock apart. This is called frost wedging or ice wedging.
6. A statue made of marble is placed outdoors. Over many years, the details become less defined. What caused this?
Answer: Chemical weathering from acid rain. Marble is made of calcium carbonate, which reacts with acids in rainwater, slowly dissolving the stone's surface.
7. What agent of erosion creates sand dunes in a desert?
Answer: Wind. Wind picks up and carries sand particles, depositing them in mounds called dunes when the wind slows down.
8. How can farmers prevent soil erosion on their fields?
Answer: Farmers can plant cover crops, use terracing on hillsides, practice contour plowing, create windbreaks with trees, and avoid leaving soil bare.
9. What is a delta, and how does it form?
Answer: A delta is a landform created at the mouth of a river where it meets a larger body of water. It forms when the river slows down and deposits the sediment it has been carrying.
10. Explain how the same rock can become different types of rocks through the rock cycle.
Answer: A rock can be weathered and eroded into sediments that form sedimentary rock. That rock can be buried and transformed by heat and pressure into metamorphic rock. If melted, it becomes magma that cools into igneous rock. Any rock type can become any other through these processes.
Next Steps
- Review any concepts that felt challenging
- Move on to the next lesson when ready
- Return to practice problems periodically for review