Section 5.6 on Metamorphic Rocks, explaining rock transformation processes.

Let’s go step by step to answer each question based on the passage and diagrams.

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Question 1: What causes rocks to change into magma?

From Figure 2 (the rock cycle diagram), we see that “melting” turns rocks into magma. The text also says: “When rocks are heated enough, they melt and become magma.” So heat is what causes this change.

→ Answer: Heat (or high temperature)

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Question 2: What happens when magma cools and hardens?

Again, looking at Figure 2: Magma → cooling/hardening → igneous rock. The text confirms: “When magma cools and hardens, it becomes igneous rock.”

→ Answer: It becomes igneous rock

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Question 3: How do sedimentary rocks form from other types of rocks?

Figure 2 shows: Any rock type → weathering/erosion → sediments → compaction/cementation → sedimentary rock.

The text says: “Sedimentary rocks form when pieces of other rocks (sediments) are pressed together and cemented.”

So, other rocks break down into small pieces (sediments), then those pieces get squished and glued together.

→ Answer: Other rocks break into small pieces (sediments), which are then compacted and cemented together to form sedimentary rocks.

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Question 4: How does a metamorphic rock with high temperature affect limestone?

Look at Figure 2: Limestone (a sedimentary rock) → under heat and pressure → becomes marble (a metamorphic rock).

The text says: “Metamorphic rocks form when existing rocks are changed by heat and pressure.” And specifically for limestone: “Limestone changes into marble when it is subjected to high temperatures and pressures.”

→ Answer: High temperature (and pressure) changes limestone into marble, a metamorphic rock.

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Question 5: How can you tell if a rock has been altered?

This one requires thinking about the whole process. Rocks change due to heat, pressure, or being broken down and reformed. Signs of alteration include:

- Change in texture (e.g., crystals growing larger)
- Change in mineral composition
- Layering or banding (in metamorphic rocks)
- Presence of fossils only in sedimentary rocks — so if a rock looks like it should have fossils but doesn’t, maybe it was altered
- If it’s melted and cooled again, it might look different from its original form

But the simplest way from the diagram: Look at where the rock came from in the rock cycle. If it went through melting, heating, pressure, or breaking down — it’s been altered.

Also, the text says: “Rocks can change from one type to another over time.” So if a rock doesn’t match how it originally formed, it’s been altered.

→ Answer: You can tell a rock has been altered if its appearance, texture, or minerals don’t match how it originally formed — for example, if it has bands or new crystals from heat and pressure, or if it melted and became igneous rock instead of staying sedimentary or metamorphic.

*(Note: Since this is a short-answer homework, keep it simple.)*

Better simplified version:

→ Answer: A rock has been altered if it changed type — like turning from sedimentary to metamorphic because of heat and pressure, or melting into magma and becoming igneous rock. You can tell by its texture, layers, or minerals.

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Now let’s write clean final answers for each:

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Final Answer:
1. Heat (or high temperature)
2. It becomes igneous rock
3. Other rocks break into sediments, which are then compacted and cemented together
4. High temperature (and pressure) changes limestone into marble
5. By seeing if its texture, minerals, or structure show signs of change — like banding, new crystals, or having turned into a different rock type