Yr 8 science revision Flashcards
1
Q
- Name the three types of plate boundaries.
A
- Convergent, divergent, transform.
2
Q
- How is lava different to magma
A
- Lava is the molten rock that erupts out of a volcano and is on the surface whereas Magma is molten rock that is under the ground.
3
Q
- How do convection currents, slab pull, and ridge push relate to the tectonic plates moving?
A
Both forces unevenly contribute to the subduction of an oceanic tectonic plate into the Earth’s mantle, contributing to the driving of convection currents.
4
Q
- What are the four layers of the Earth?
A
- Crust, Mantle, Outer Core, Inner Core
5
Q
- What is the difference between an extrusive igneous rock and an intrusive igneous rock?
A
- An extrusive igneous rock is formed from lava. It cools down very quickly creating small to no crystals inside the rock whereas intrusive igneous rocks are formed when magma slowly cools down underneath the surface creating large crystals.
6
Q
- Explain continental drift
A
movements of continents relative to one another
6
Q
- Give an example of a landform or natural disaster that occurs on a Transform Boundary.
A
- Large Earthquakes or Tsunamis
7
Q
- Give an example of a landform or natural disaster that occurs on a divergent boundary.
A
- Mid ocean ridges, rift valleys, shield volcanoes, small earthquakes
8
Q
- Give an example of a landform or natural disaster that occurs on a convergent boundary.
A
- Fold mountains, ocean trenches, island arcs, stratovolcanoes, large earthquakes
9
Q
Describe the process of subduction
A
- Subduction is when an oceanic plate runs into a continental plate and slides beneath it on a convergent boundary. One tectonic plate is heavier and sinks into the mantle to be remelted and recycled.
10
Q
- What is the shape of a Shield Volcano?
A
Gentle slopes
11
Q
What is the shape of a Stratovolcano?
A
- Tall, steep, conical
12
Q
What is sea floor spreading?
A
- Sea floor spreading is when new and fresh areas of oceanic crust are formed because of magma coming to the surface. This was one piece of evidence that supported Alfred’s continental drift theory.
13
Q
- What term best describes each of the following: a) plates that collide together, b) plates that slide parallel passed each other but in opposite directions and c) where new crust is created.
A
- A) Convergent B) Transform C) Divergent
14
Q
- What are the 7 major tectonic plates?
A
- Australia, Antarctica, North America, South America, Eurasia, Africa, Pacific
15
Q
- What geological structure can occur on a convergent plate boundary?
A
- Fold mountains, ocean trenches, island arcs, stratovolcanoes.
16
Q
- How are fossils formed?
A
- Fossils are formed when sediment covers an organism quickly. The sediment encases the remains of the organism. Water dissolves the bones/shells etc leaving behind the imprint. This is a natural mould. Water rich in minerals will fill this space, crystals can form creating a fossil.
16
Q
- What geological structure can occur on a divergent plate boundary?
A
- Mid ocean ridges, rift valleys, shield volcanoes
17
Q
- Explain the unique features of a Shield Volcano.
A
- A shield volcano – has gentle slopes, lava is runny and flows very quickly, it rarely explodes because there is less gas pressure in the runny lava.
18
Q
- Explain why intrusive igneous rocks have large crystals.
A
- Because the cool very slowly
19
Q
- Explain the unique features of a Stratovolcano.
A
- A stratovolcano – has tall steep sides shaped into a conical shape, highly explosive
20
Q
- Explain why extrusive igneous rocks have small to no crystals.
A
- because the cool from lava very quickly
21
Q
- Explain why fossils are not found in igneous rock.
A
- Fossils are not found in igneous rock because the intense heat and pressure will destroy the fossil. They can be found in metamorphic rock but may be deformed.
22
Q
- Explain how metamorphic rocks are made. Give an example of a metamorphic rock.
A
- Metamorphic rocks are made when other rock is put under heat and pressure, causes the original rock to be deformed, folded and changed due to the heat and pressure and recrystallisation. They may contain layers, deformed fossils, large crystals and are very dense. They are very strong. An example of Metamorphic rock – MARBLE
23
Q
Explain how igneous rocks are made. Give an example of an igneous rock.
A
- Igneous Rock are formed from the cooling of lava or magma. Some examples are PUMICE, OBSIDIAN, BASALT.
24
Q
- Explain how sedimentary rocks are made. Give an example of a sedimentary rock.
A
Sedimentary rocks are made from the collection or sediment (fragments of weathered rock, plant or animal material. The sediment collects and more and more layers are added and compacted together. Fossils can be found in this rock. This compaction then cements by chemicals to form a solid rock. EG LIMESTONE, SANDSTONE
25
Q
- What plate boundary do earthquakes happen on?
A
- Convergent (Large Earthquakes) Divergent (small Earthquakes) Transform ( large Earthquakes)
26
Q
Draw the Rock Cycle.
A
27
Q
- In your own words explain the difference between the theory of continental drift and the theory of plate tectonics.
A
- Continental drift is the theory proposed by Wegener that explained how the continents move over time. He explained how the continents were like a jigsaw and all the pieces fit together. Fossil and rock records show how these pieces fit together.
28
Q
- List the four main pieces of evidence Wegner used to support his theory of continental drift.
A
- Four pieces of evidence
29
Q
- Why is Obsidian an example of extrusive igneous rock?
A
- Because it has small to no crystals which means it came from very quick cooling lava
30
Q
- Compare Shield and Stratovolcanoes.
A
- A shield volcano sdkflsjdfklaj whereas a stratovolcano sdfsdfadf
31
Q
- What rock is formed when magma cools down slowly?
A
- Intrusive igneous rock
32
Q
- What is weathering?
A
- Weathering is the process of rock being broken down into smaller pieces and eventually turn into sediment. It can be caused by physical processes, biological processes and chemical processes. This is the first step in making sedimentary rock.
33
Q
- What is erosion?
A
- Erosion is the transportation of the weathered rock usually by wind or water. Natural forces moves the weathered rock to a location (ocean or lake) where it is deposited.
34
Q
- What can sedimentary rocks be formed from?
A
- Remains of living organisms and the remains of non-living (shells)
35
Q
- What is subduction?
A
- Subduction is when an oceanic plate runs into a continental plate and slides beneath it. The heavier plate will sink into the mantle where the rock is remelted and recycled.
