Rocks, Landscapes & Water — Chapter quiz · Earth & Space Science, Grade 9

Identify Earth materials and explain how rock, water, and surface processes shape landscapes.

Problem 1

What is the Mohs hardness of quartz?
Answer and explanation

7

Quartz is reference mineral #7 on the Mohs hardness scale.

Problem 2

Which mineral property is tested by rubbing the mineral across an unglazed porcelain plate?
  1. Luster
  2. Streak
  3. Specific gravity
  4. Crystal shape
Answer and explanation

Streak

Streak is the color of a mineral's powder, revealed by rubbing it on an unglazed porcelain plate; it's more reliable than color.

Problem 3

Which three rock types make up the rock cycle?
  1. Igneous, sedimentary, metamorphic
  2. Granite, marble, quartzite
  3. Mineral, crystal, sediment
  4. Magma, lava, ash
Answer and explanation

Igneous, sedimentary, metamorphic

The rock cycle recycles Earth's materials among igneous, sedimentary, and metamorphic rock.

Problem 4

Explain why the rock cycle is described as having no fixed starting point or ending point.
Answer and explanation

Any rock type can transform into any other rock type depending on which process — cooling, weathering and erosion, lithification, metamorphism, or melting — acts on it next, so you can enter the loop at any rock type and it keeps going indefinitely.

Problem 5

Compaction and cementation of loose sediment into solid rock is called…
  1. Metamorphism
  2. Lithification
  3. Crystallization
  4. Weathering
Answer and explanation

Lithification

Lithification is the combined process of compaction and cementation that turns sediment into sedimentary rock.

Problem 6

Which rock type is most likely to contain fossils?
  1. Igneous
  2. Sedimentary
  3. Foliated metamorphic
  4. Non-foliated metamorphic
Answer and explanation

Sedimentary

Sedimentary rock forms from settling layers of sediment without melting, so it commonly preserves fossils.

Problem 7

Which statement correctly describes weathering?
  1. It transports sediment far from its source
  2. It breaks down rock in place, without moving it
  3. It only happens underwater
  4. It always involves melting rock
Answer and explanation

It breaks down rock in place, without moving it

Weathering breaks rock down where it sits; erosion is the separate process that moves the pieces away.

Problem 8

A retreating glacier deposits a moraine that gains about 3 meters of debris thickness every 200 years. At that rate, how many meters thick would it be after 2,000 years?
Answer and explanation

30 meters

2,000 ÷ 200 = 10 periods; 10 × 3 = 30 meters.

Problem 9

Which is not a mineral?
  1. Quartz
  2. Calcite
  3. Coal
  4. Halite
Answer and explanation

Coal

Coal forms from plant remains, so it is organic in origin and lacks a definite composition and crystal structure.

Problem 10

Explain how a mineral's internal structure accounts for both its cleavage and its hardness.
Answer and explanation

Both follow from how atoms are bonded. Where bonds are weaker along particular planes, the mineral splits there, giving cleavage in those directions. Where bonding is strong in all directions, the mineral resists scratching and ranks high in hardness. Properties that seem separate at the hand-sample scale are consequences of the same atomic arrangement.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 11

Independent chapter check: A specimen has mass 54 g and displaces water from 20 to 38 mL when fully immersed without bubbles. Find its density and explain what additional evidence is needed to identify its mineral.
Answer and explanation

Volume is 18 mL = 18 cm³, so density is 54/18 = 3 g/cm³. Use hardness, streak, cleavage and other characteristic observations; density alone may match several candidates.

Find displaced volume: 38−20 = 18 cm³.

Calculate density: 54/18 = 3 g/cm³.

Compare several tests and uncertainty rather than naming a mineral from one value.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 12

Which pair of processes directly converts sediment into sedimentary rock?
  1. Melting and cooling
  2. Compaction and cementation
  3. Heat and pressure
  4. Weathering and erosion
Answer and explanation

Compaction and cementation

Weathering and erosion produce the sediment; compaction and cementation lithify it.

Problem 13

A single outcrop shows all three rock types. Explain how that is possible.
Answer and explanation

Rocks of different origins can be brought together by geological processes: magma can intrude into sedimentary layers and cool as igneous rock, and the heat of that intrusion can metamorphose the rock it touches. Later uplift and erosion then expose all three at one surface. The arrangement records a sequence of events rather than simultaneous formation.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 14

Independent chapter check: A rock contains sand grains cemented together. A student calls cementation the same as cooling molten sand. Distinguish the two pathways and name an observation that could help test the interpretation.
Answer and explanation

Cementation binds deposited grains through mineral precipitation; cooling a melt forms igneous material. Preserved grain boundaries, sedimentary textures and field relationships help test a cemented-sediment interpretation. Melting is not required for sandstone.

Cementation binds deposited grains through mineral precipitation; cooling a melt forms igneous material. Preserved grain boundaries, sedimentary textures and field relationships help test a cemented-sediment interpretation. Melting is not required for sandstone.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 15

Visible fossil shells in a rock indicate it is
  1. igneous
  2. sedimentary
  3. metamorphic
  4. volcanic
Answer and explanation

sedimentary

Fossils survive burial in sediment; melting or intense metamorphism would destroy them.

Problem 16

Explain how grain size and texture let you identify a rock's type and its history.
Answer and explanation

Texture records the conditions of formation. Interlocking crystals point to cooling from a melt, with large crystals meaning slow underground cooling and fine ones rapid surface cooling. Rounded, sorted grains cemented together indicate transport and deposition as sediment. Aligned or banded minerals indicate directed pressure without melting. Reading the texture therefore reconstructs the process, not just the category.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 17

Independent chapter check: A specimen has interlocking crystals but no foliation. Is it necessarily igneous? Explain two possible histories and the evidence that would help distinguish them.
Answer and explanation

No. Cooling a melt can yield an igneous crystalline rock, while solid-state recrystallization can yield a nonfoliated metamorphic rock. Mineral composition, texture details, contacts and field relationships help distinguish the histories.

No. Cooling a melt can yield an igneous crystalline rock, while solid-state recrystallization can yield a nonfoliated metamorphic rock. Mineral composition, texture details, contacts and field relationships help distinguish the histories.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 18

Which sequence is correct?
  1. Erosion, weathering, deposition
  2. Weathering, erosion, deposition
  3. Deposition, weathering, erosion
  4. Weathering, deposition, erosion
Answer and explanation

Weathering, erosion, deposition

Rock is broken down, the pieces are transported, then they are laid down.

Problem 19

A landscape has deep soil in one valley and bare rock on the ridge above. Explain.
Answer and explanation

On the ridge, gravity and running water remove weathered material as fast as it forms, so little accumulates and rock stays exposed. In the valley the gradient is gentler and material arriving from upslope is deposited rather than carried away, so soil builds up. The difference reflects the balance between the rate of weathering and the rate of removal at each site.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 20

Independent chapter check: Trial A produces 12 g of sediment in 120 mL runoff; trial B 9 g in 60 mL. Compare total sediment export and concentration, then name two conditions to control when testing a surface cover.
Answer and explanation

B exports less mass (9 vs 12 g) but greater concentration (0.15 vs 0.10 g/mL). Control rain input, slope, material and collection interval, except for the planned cover change.

Calculate A: 12/120 = 0.10 g/mL.

Calculate B: 9/60 = 0.15 g/mL.

Distinguish total export from concentration and match test conditions.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 21

Recharge is 150 units; pumping is 110 and natural outflow is 55. Find storage change.
Answer and explanation

-15 units

150 − 110 − 55 = −15.

Problem 22

A porous material transmits water slowly. Explain why this is possible.
Answer and explanation

Its pores can be small or poorly connected, so permeability is low despite pore space.

Problem 23

Independent chapter check: A catchment begins with 300 m³ of stored water. Over one month it receives 100 m³ and loses 70 m³ by outflow/evapotranspiration plus 45 m³ by withdrawal. Find storage change and final storage. Explain why high porosity alone would not guarantee fast recharge.
Answer and explanation

Storage change is 100−70−45 = −15 m³ and final storage is 285 m³. Transmission also depends on connected pathways, permeability, gradients and conditions; porosity alone is a storage fraction.

Combine outputs: 70+45 = 115 m³.

Change is −15 m³; add to initial 300 m³ to get 285 m³.

Distinguish pore-space amount from connected transmission.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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