Compare igneous, sedimentary and metamorphic rocks, fossil formation, permeability and soil horizons. Review suitability for your learners before teaching.
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Worksheet StudioPractice pack · Ages 10-12
Rocks, fossils & soil layers
Take your time. Show your thinking.
1. On the Mohs hardness scale of minerals from 1 (softest, talc) to 10 (hardest), which natural mineral is the hardest (10) and can scratch all other minerals: diamond or chalk?
Topsoil → Subsoil → Bedrock
2. What is the dark, nutrient-rich organic material in topsoil formed from decomposed leaves, roots and animal remains: humus or magma?
Topsoil → Subsoil → Bedrock
3. In which type of rock are fossils of ancient plants and animals almost always found: sedimentary rock or igneous rock?
Topsoil → Subsoil → Bedrock
4. Which soil type has microscopic particles that pack tightly together, holding water and feeling sticky when wet: clay soil or sandy soil?
Topsoil → Subsoil → Bedrock
5. Which sedimentary rock is formed mainly from the calcium carbonate shells and skeletons of marine organisms and coral: limestone (and chalk) or granite?
Topsoil → Subsoil → Bedrock
6. How do earthworms help keep garden and farm soil healthy for plants: their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients, or they eat rocks into lava?
Topsoil → Subsoil → Bedrock
7. Which lightweight volcanic igneous rock is so full of trapped gas bubbles that it can float on water: pumice or marble?
Topsoil → Subsoil → Bedrock
8. In a vertical soil profile, which uppermost layer contains the most humus, plant roots and soil organisms like earthworms: topsoil (A horizon) or solid bedrock?
Topsoil → Subsoil → Bedrock
9. Which of the three main rock groups forms when molten magma or lava cools and solidifies (such as granite and basalt): igneous rock or sedimentary rock?
Topsoil → Subsoil → Bedrock
10. What is the solid, unweathered layer of rock that lies beneath the subsoil at the bottom of a soil profile: bedrock or topsoil?
Topsoil → Subsoil → Bedrock
11. When fine-grained mudstone or shale is compressed by mountain-building forces, what metamorphic rock does it form that splits into flat, waterproof sheets used for roofing: slate or chalk?
Topsoil → Subsoil → Bedrock
12. What is soil made of: a mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms, or pure crushed glass?
Topsoil → Subsoil → Bedrock
12 questions · Seed 45 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 10-12
Rocks, fossils & soil layers
Answers and reasoning. Review before teaching.
1. On the Mohs hardness scale of minerals from 1 (softest, talc) to 10 (hardest), which natural mineral is the hardest (10) and can scratch all other minerals: diamond or chalk?
Diamond
Diamond ranks 10 on the Mohs hardness scale because of its strong three-dimensional covalent carbon lattice.
2. What is the dark, nutrient-rich organic material in topsoil formed from decomposed leaves, roots and animal remains: humus or magma?
Humus
Humus retains moisture and supplies essential mineral nutrients to growing plant roots.
3. In which type of rock are fossils of ancient plants and animals almost always found: sedimentary rock or igneous rock?
Sedimentary rock
Sedimentary layers gently bury remains in mud or sand; the extreme heat of magma destroys fossils in igneous rock.
4. Which soil type has microscopic particles that pack tightly together, holding water and feeling sticky when wet: clay soil or sandy soil?
Clay soil
Tiny clay particles have tiny pores that trap water and become sticky when wet and hard when baked dry.
5. Which sedimentary rock is formed mainly from the calcium carbonate shells and skeletons of marine organisms and coral: limestone (and chalk) or granite?
Limestone (and chalk)
Limestone is a carbonate sedimentary rock built from ancient marine shells and coral reefs.
6. How do earthworms help keep garden and farm soil healthy for plants: their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients, or they eat rocks into lava?
Their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients
Earthworms aerate the soil, improve drainage and recycle organic matter into plant nutrients.
7. Which lightweight volcanic igneous rock is so full of trapped gas bubbles that it can float on water: pumice or marble?
Pumice
Pumice forms from frothy lava rich in gas bubbles, giving it a density lower than water.
8. In a vertical soil profile, which uppermost layer contains the most humus, plant roots and soil organisms like earthworms: topsoil (A horizon) or solid bedrock?
Topsoil (A horizon)
Topsoil is the fertile surface layer where seeds germinate and most roots and decomposers live.
9. Which of the three main rock groups forms when molten magma or lava cools and solidifies (such as granite and basalt): igneous rock or sedimentary rock?
Igneous rock
Igneous rocks crystallise from molten rock either underground (magma) or on the surface (lava).
10. What is the solid, unweathered layer of rock that lies beneath the subsoil at the bottom of a soil profile: bedrock or topsoil?
Bedrock
Bedrock is the parent solid rock beneath loose soil and weathered regolith.
11. When fine-grained mudstone or shale is compressed by mountain-building forces, what metamorphic rock does it form that splits into flat, waterproof sheets used for roofing: slate or chalk?
Slate
Slate is a foliated, impermeable metamorphic rock that cleaves into flat tiles.
12. What is soil made of: a mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms, or pure crushed glass?
A mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms
Healthy soil combines mineral particles from weathered rock with organic humus, air spaces and water.
12 questions · Seed 45 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 10-12
Rocks, fossils & soil layers
Take your time. Show your thinking.
1. On the Mohs hardness scale of minerals from 1 (softest, talc) to 10 (hardest), which natural mineral is the hardest (10) and can scratch all other minerals: diamond or chalk?
Topsoil → Subsoil → Bedrock
2. What is the dark, nutrient-rich organic material in topsoil formed from decomposed leaves, roots and animal remains: humus or magma?
Topsoil → Subsoil → Bedrock
3. In which type of rock are fossils of ancient plants and animals almost always found: sedimentary rock or igneous rock?
Topsoil → Subsoil → Bedrock
4. Which soil type has microscopic particles that pack tightly together, holding water and feeling sticky when wet: clay soil or sandy soil?
Topsoil → Subsoil → Bedrock
5. Which sedimentary rock is formed mainly from the calcium carbonate shells and skeletons of marine organisms and coral: limestone (and chalk) or granite?
Topsoil → Subsoil → Bedrock
6. How do earthworms help keep garden and farm soil healthy for plants: their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients, or they eat rocks into lava?
Topsoil → Subsoil → Bedrock
7. Which lightweight volcanic igneous rock is so full of trapped gas bubbles that it can float on water: pumice or marble?
Topsoil → Subsoil → Bedrock
8. In a vertical soil profile, which uppermost layer contains the most humus, plant roots and soil organisms like earthworms: topsoil (A horizon) or solid bedrock?
Topsoil → Subsoil → Bedrock
9. Which of the three main rock groups forms when molten magma or lava cools and solidifies (such as granite and basalt): igneous rock or sedimentary rock?
Topsoil → Subsoil → Bedrock
10. What is the solid, unweathered layer of rock that lies beneath the subsoil at the bottom of a soil profile: bedrock or topsoil?
Topsoil → Subsoil → Bedrock
11. When fine-grained mudstone or shale is compressed by mountain-building forces, what metamorphic rock does it form that splits into flat, waterproof sheets used for roofing: slate or chalk?
Topsoil → Subsoil → Bedrock
12. What is soil made of: a mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms, or pure crushed glass?
Topsoil → Subsoil → Bedrock
12 questions · Seed 45 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 10-12
Rocks, fossils & soil layers
Answers and reasoning. Review before teaching.
1. On the Mohs hardness scale of minerals from 1 (softest, talc) to 10 (hardest), which natural mineral is the hardest (10) and can scratch all other minerals: diamond or chalk?
Diamond
Diamond ranks 10 on the Mohs hardness scale because of its strong three-dimensional covalent carbon lattice.
2. What is the dark, nutrient-rich organic material in topsoil formed from decomposed leaves, roots and animal remains: humus or magma?
Humus
Humus retains moisture and supplies essential mineral nutrients to growing plant roots.
3. In which type of rock are fossils of ancient plants and animals almost always found: sedimentary rock or igneous rock?
Sedimentary rock
Sedimentary layers gently bury remains in mud or sand; the extreme heat of magma destroys fossils in igneous rock.
4. Which soil type has microscopic particles that pack tightly together, holding water and feeling sticky when wet: clay soil or sandy soil?
Clay soil
Tiny clay particles have tiny pores that trap water and become sticky when wet and hard when baked dry.
5. Which sedimentary rock is formed mainly from the calcium carbonate shells and skeletons of marine organisms and coral: limestone (and chalk) or granite?
Limestone (and chalk)
Limestone is a carbonate sedimentary rock built from ancient marine shells and coral reefs.
6. How do earthworms help keep garden and farm soil healthy for plants: their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients, or they eat rocks into lava?
Their burrows let air and rainwater reach roots, and their castings enrich the soil with nutrients
Earthworms aerate the soil, improve drainage and recycle organic matter into plant nutrients.
7. Which lightweight volcanic igneous rock is so full of trapped gas bubbles that it can float on water: pumice or marble?
Pumice
Pumice forms from frothy lava rich in gas bubbles, giving it a density lower than water.
8. In a vertical soil profile, which uppermost layer contains the most humus, plant roots and soil organisms like earthworms: topsoil (A horizon) or solid bedrock?
Topsoil (A horizon)
Topsoil is the fertile surface layer where seeds germinate and most roots and decomposers live.
9. Which of the three main rock groups forms when molten magma or lava cools and solidifies (such as granite and basalt): igneous rock or sedimentary rock?
Igneous rock
Igneous rocks crystallise from molten rock either underground (magma) or on the surface (lava).
10. What is the solid, unweathered layer of rock that lies beneath the subsoil at the bottom of a soil profile: bedrock or topsoil?
Bedrock
Bedrock is the parent solid rock beneath loose soil and weathered regolith.
11. When fine-grained mudstone or shale is compressed by mountain-building forces, what metamorphic rock does it form that splits into flat, waterproof sheets used for roofing: slate or chalk?
Slate
Slate is a foliated, impermeable metamorphic rock that cleaves into flat tiles.
12. What is soil made of: a mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms, or pure crushed glass?
A mixture of weathered rock particles (sand, silt, clay), decaying organic matter (humus), water, air and living organisms
Healthy soil combines mineral particles from weathered rock with organic humus, air spaces and water.
12 questions · Seed 45 · Age guidance, not curriculum certification