Bazile's 6th grade Earth Science Review

Rocks and Minerals

100

What is a mineral?

A mineral is a naturally occurring, inorganic solid with a specific chemical composition and a crystalline structure.

200

 Name a property used to identify minerals.

• Hardness: Measured using the Mohs scale, it determines a mineral's resistance to being scratched.
• Color: The visible color of the mineral, though not always reliable due to impurities.
• Streak: The color of a mineral's powdered form when rubbed on a streak plate.
• Luster: How a mineral reflects light, e.g., metallic or non-metallic.
• Cleavage: How a mineral breaks along specific planes of weakness.
• Fracture: The pattern in which a mineral breaks when it does not follow cleavage planes.
• Density/Specific Gravity: The mineral's mass relative to its volume.
• Crystal Form: The shape of the mineral's crystals if it has had time and space to form properly.
• Magnetism: Some minerals, like magnetite, are naturally magnetic.
• Reaction to Acid: Minerals like calcite fizz when exposed to dilute hydrochloric acid.

300

How can rocks be classified?

Rocks can be classified into three main types based on how they are formed:

1. Igneous: Formed from cooled and solidified magma or lava.
2. Sedimentary: Formed from the compaction and cementation of sediments.
3. Metamorphic: Formed when existing rocks are transformed by heat and pressure.

400

Describe the rock cycle in simple terms.

The rock cycle is a continuous process where rocks change from one type to another over time:

• Igneous rocks form from cooled magma or lava.
• Weathering and erosion break rocks into sediments, which form sedimentary rocks through compaction and cementation.
• Heat and pressure transform rocks into metamorphic rocks.
• Metamorphic or any other rock can melt into magma, starting the cycle again.

500

What is the difference between igneous, sedimentary, and metamorphic rocks?

• Igneous Rocks: Formed from the cooling and solidification of magma or lava (e.g., basalt, granite).
• Sedimentary Rocks: Formed from sediments compacted and cemented together (e.g., sandstone, limestone).
• Metamorphic Rocks: Formed when existing rocks are altered by heat, pressure, or chemical processes (e.g., marble, schist).

Weathering, Erosion, Deposition & Soil

100

 What is the process of weathering?

Weathering is the breakdown of rocks and minerals into smaller particles by physical, chemical, or biological processes. It occurs on or near the Earth's surface and does not involve the movement of materials.

200

Name one agent of erosion.

• Water: Rivers, rain, waves, and glaciers erode materials and transport them.
• Wind: Moves loose particles, especially in deserts and open areas, creating landforms like sand dunes.
• Ice (Glaciers): Glaciers scrape and carry rocks and sediments as they move slowly over land.
• Gravity: Causes mass movements like landslides, mudslides, and rockfalls.
• Human Activity: Farming, deforestation, construction, and mining accelerate erosion by disturbing the soil.

300

Describe the role of soil in supporting plant life.

Soil provides plants with essential nutrients, water, and a stable medium for their roots to anchor. It also contains organic matter, such as decomposed plants and organisms, which enhances fertility and supports plant growth.

400

 How does deposition affect landforms?

• Forming deltas at river mouths.
• Building up sand dunes in deserts or coastal areas.
• Accumulating sediments to create fertile floodplains.

500

What are the different layers of soil composed of?

1. O Horizon: Organic material, including decomposed leaves and plant matter.
2. A Horizon (Topsoil): Rich in humus and nutrients; crucial for plant growth.
3. E Horizon: Zone of leaching where minerals and nutrients are carried downward.
4. B Horizon (Subsoil): Contains minerals, clay, and deposits leached from the layers above.
5. C Horizon: Composed of partially weathered parent material.
6. R Horizon: Solid bedrock beneath the soil layers.

Plate Tectonics & Paleontology

100

What are the four main layers of the Earth?

1. Crust: The outermost layer, thin and solid, where we live.
2. Mantle: A thick layer of semi-solid rock beneath the crust.
3. Outer Core: A layer of molten (liquid) iron and nickel.
4. Inner Core: A solid sphere composed primarily of iron and nickel at the Earth's center.

200

 Describe the difference between a convergent boundary and a divergent boundary

• Convergent Boundary: Where two tectonic plates move toward each other, often causing one plate to subduct beneath the other, leading to mountain formation, volcanic activity, or deep ocean trenches.
• Divergent Boundary: Where two tectonic plates move apart, creating new crust as magma rises to the surface, such as at mid-ocean ridges or rift valleys.

300

How do fossils provide evidence of Earth's changing surface?

• Fossils of the same species found on widely separated continents suggest that the continents were once connected (supporting the theory of plate tectonics).
• Fossilized marine life found on mountain tops indicates that these areas were once underwater and have been uplifted through tectonic processes.

400

What causes earthquakes according to plate tectonics?

Earthquakes occur when tectonic plates interact at their boundaries. Stress builds up as plates grind, collide, or slide past each other. When the stress exceeds the rocks' ability to withstand it, the energy is released as seismic waves, causing an earthquake.

500

Explain how convection currents affect the movement of tectonic plates.

Convection currents in the Earth's mantle are caused by the heat from the core. Hot, less dense material rises, while cooler, denser material sinks, creating a circulating flow. These currents exert forces on the base of tectonic plates, driving their movement and causing phenomena such as seafloor spreading and subduction.

Conservation of Natural Resources

100

What are renewable energy resources?

Renewable energy resources are energy sources that are replenished naturally and sustainably over time. They are derived from natural processes that are constantly renewed, such as sunlight, wind, and water cycles.

200

Name two examples of nonrenewable energy resources.

• Coal
• Oil
• natural gas

300

How do renewable energy resources contribute to conservation?

Renewable energy resources help conserve natural resources by reducing dependence on nonrenewable resources, which are limited and take millions of years to form. Using renewables like solar and wind minimizes habitat destruction, decreases pollution, and lowers greenhouse gas emissions, preserving ecosystems and mitigating climate change.

400

What is one way individuals can help conserve natural resources?

using energy-efficient appliances, turning off lights when not needed, and opting for public transportation or biking instead of driving.

500

Explain how human activity can impact the quality of natural resources.

• Water pollution from industrial waste can make freshwater supplies unsafe.
• Air pollution from burning fossil fuels contributes to smog and acid rain.
• Deforestation reduces biodiversity and disrupts ecosystems, impacting soil and water quality.

Bonus

100

What is an example of a natural resource?

water, air, sunlight, soil, plants, animals, minerals like iron and gold, fossil fuels like coal and oil, wind, and forests.

200

What is a fossil?

A fossil is the preserved remains, impression, or trace of an organism that lived in the past, offering evidence about Earth's history and evolutionary processes.

300

Name a layer of soil and its importance.

The O Horizon (Organic Layer) is important because it contains decomposed organic matter (humus), which enriches the soil and supports plant growth.

400

What is the rock cycle?

The rock cycle is the ongoing process by which rocks are formed, broken down, and transformed into different types

500

Name a geologic event caused by plate tectonics.

• Earthquakes: Sudden release of energy along plate boundaries or fault lines.
• Volcanic Eruptions: Occur at convergent boundaries (subduction zones) or divergent boundaries where magma reaches the surface.
• Tsunamis: Triggered by underwater earthquakes, volcanic eruptions, or landslides at plate boundaries.
• Mountain Formation: Created by the collision of tectonic plates (e.g., the Himalayas at a convergent boundary).
• Rift Valley Formation: Occurs at divergent boundaries where plates move apart (e.g., East African Rift).
• Seafloor Spreading: Happens at mid-ocean ridges where new crust is formed as plates diverge.
• Island Arc Formation: Chains of volcanic islands formed at oceanic-oceanic convergent boundaries (e.g., the Aleutian Islands).
• Fault Formation: Crustal fractures resulting from plate movements (e.g., the San Andreas Fault).
• Trench Formation: Deep ocean trenches form at subduction zones where one plate sinks beneath another (e.g., the Mariana Trench).
• Continental Drift: The slow movement of continents over geological time due to plate motion.