Worked example
Lava cools and becomes solid rock. Which rock group forms?
Answer & why
Answer: igneous rock
Cooling and solidification of molten rock produces igneous rock.
Grade 4 · Science
Classify rocks by how they form
Use formation evidence to distinguish igneous, sedimentary and metamorphic rocks.
6 authored questions + worked example
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All questions
All 6 authored questions for this skill.
Question 1
Buried limestone changes under heat and pressure without melting. Which group results?
- sedimentary rock
- metamorphic rock
- insufficient formation evidence
- igneous rock
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: metamorphic rock
Existing rock changes in the solid state under heat and pressure.
Question 2
A rock is gray, and nothing is known about its structure or formation. Can its formation group be identified from this alone?
- igneous rock
- insufficient formation evidence
- sedimentary rock
- metamorphic rock
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: insufficient formation evidence
Different rock groups can have the same color.
Question 3
Magma cools slowly below Earth’s surface and crystallizes. Which rock group results?
- metamorphic rock
- insufficient formation evidence
- igneous rock
- sedimentary rock
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: igneous rock
Molten rock that cools underground also forms igneous rock.
Question 4
Layers of mud are compressed and cemented into rock. Which group is described?
- metamorphic rock
- insufficient formation evidence
- igneous rock
- sedimentary rock
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: sedimentary rock
The rock forms from accumulated sediments.
Question 5
Lava cools and becomes solid rock. Which rock group forms?
- sedimentary rock
- metamorphic rock
- insufficient formation evidence
- igneous rock
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: igneous rock
Cooling and solidification of molten rock produces igneous rock.
Question 6
Sand grains are buried, compacted and cemented together. Which group forms?
- metamorphic rock
- sedimentary rock
- igneous rock
- insufficient formation evidence
A hint
Igneous rock forms when molten rock cools and solidifies.
Answer & why
Answer: sedimentary rock
Compaction and cementation turn sediments into sedimentary rock.