8th Grade Earth Sciences Assessment Study Guide
Lunar Cycle, Eclipses,
- Draw and label the phases of the Moon
- During a solar eclipse what is the difference between an umbra and penumbra?
- Describe how the Earth’s seasons occur.
- What causes the movements of the tides?
- Draw a diagram of a spiral galaxy, an irregular galaxy and an elliptical galaxiy
Rock Cycle
- Describe the processes involved in the formation of sedimentary rock ( weathering, erosion, deposition, compaction and cementation).
- Describe the processes involved in the formation of metamorphic and igneous rock.
Plate Tectonics
- What is the force in the mantle that moves the continents?
- Name and describe the three plate boundaries.
- Describe the processes of Continental Drift and Sea Floor Spreading.
- What features are associated with each of the plate boundaries?
- What is the difference between the asthenosphere and lithosphere?
Volcanoes
- Describe how volcanoes are formed at convergent (subduction) and divergent plate boundaries and at hot spots.
- What is the difference between magma and lava?
- Describe the different types of volcanoes.
Geological Processes and Natural Resources
- Identify the processes that result in the distribution of minerals
- Identify the processes that result in the distribution of fossil fuels.
Minerals
How would you test the hardness of a mineral?
Geologic time and Fossils
Describe the 3 laws of relative dating.
Which type of rock and fossil dating give the precise age of the rock or fossil?
What do fossils found in a layer of rock tell us about the conditions that existed on Earth when that rock was formed?
8th Grade Earth Sciences Assessment Study Guide
Lunar Cycle, Eclipses,
- Draw and label the phases of the Moon
- During a solar eclipse what is the difference between an umbra and penumbra?
An umbra is a full solar eclipse where the sun is completely blocked out.
A penumbra is a partial solar eclipse where the sun is partially blocked out.
- Describe how the Earth’s seasons occur.
The tilt of the Earth's causes theseasons to occur. We have hot summers and cold winters because of the tilt of the Earth's axis. The tilt of the Earth means the Earth will lean towards the Sun (Summer) or lean away from the Sun (Winter) 6 months later.
- What causes the movements of the tides?
The gravitational pull of the moon and to a lesser extent the Sun cause the tides to change
- Draw a diagram of a spiral galaxy, an irregular galaxy and an elliptical galaxy
Rock Cycle
- Describe the processes involved in the formation of sedimentary rock (weathering, erosion, deposition, compaction and cementation).
Weathering is the breaking down of rocks and material. Erosion is transportation of the weathered material. Deposition occurs when the river, lake, air does not have enough energy left to transport the rock and deposits them. Compaction occurs when rocks and material are deposited in layers and each layer gets compacted. Cementation is the process where the compacted material cements into rock.
- Describe the processes involved in the formation of metamorphic and igneous rock.
Metamorphic rock – Extreme and Pressure
Igneous rock – cooling and hardening of magma/lava
Plate Tectonics
- What is the force in the mantle that moves the continents?
Convection currents.
- Name and describe the three plate boundaries.
Converging – plates are colliding with each other.
Diverging – plates are moving away from each other.
Transform – Plates are moving along side each other.
- Describe the processes of Continental Drift and Sea Floor Spreading.
Continental drift – continental plates are moving
Sea Floor Spreading – plates are being created at divergent boundaries and destroyed at convergent plate boundaries.
- What features are associated with each of the plate boundaries?
Convergent – Mountain ranges (2 continental plates colliding), volcanoes, volcanic islands, earthquakes
Divergent – Mid ocean ridges, rift valleys and volcanoes
Transform - earthquakes
- What is the difference between the asthenosphere and lithosphere?
Lithosphere is the crust and the upper part of the mantle (the tectonic plates) and the asthenosphere is the lower mantle
Volcanoes
- Describe how volcanoes are formed at convergent (subduction) and divergent plate boundaries and at hot spots.
Convergent – plates collide, the heavier plate sinks, the rocks melt and the melted rock (magma) rises towards the surface gradually creating a volcano.
Divergent –when the plates move apart it creates a gap where magma rises through and gradually creates volcanoes.
- What is the difference between magma and lava?
Magma is molten rock below the Earth’s surface and lava is molten rock above the surface
- Describe the different types of volcanoes.
Shield volcano – gentler eruptions that occur more regularly
Composite volcano – more violent eruption that occur less regularly
Cinder cone - small, steeply sloped volcano that forms from moderately explosive eruptions of pyroclastic material
Geological Processes and Natural Resources
- Identify the processes that result in the distribution of minerals
Minerals are formed at plate boundaries where magma cools and hardens in chambers below the Earth’s surface
- Identify the processes that result in the distribution of fossil fuels.
Processes of sedimentary rock formation – Weathering, Erosion, Deposition, Compaction and Cementation
Minerals
How would you test the hardness of a mineral?
Scratch test using the Mohs hardness scale. Scratch the mineral with a harder/softer mineral.
Geologic time and Fossils
Describe the 3 laws of relative dating.
Law of Superposition – at undisturbed outcrops older rocks are found at the bottom and the younger rocks are found at the top.
Law of cross-cutting – Rocks (for example Igneous intrusions and faults) that cross other rocks are younger.
Law of Inclusion – Rocks that are found inside other rocks are older.
Which type of rock and fossil dating give the precise age of the rock or fossil?
Absolute dating
What do fossils found in a layer of rock tell us about the conditions that existed on Earth when that rock was formed?
If the fossil was a marine organism, then it is likely that that location was an ocean/lake/river.
If the fossil was a small animal, then the location could have been a grassland or rainforest.