Grade 8 · Science · Unit 5 of 5
Plate Tectonics
Moving plates, quakes and volcanoes
What your child practises
Earth's layers and moving plates, the three kinds of plate boundaries, the evidence for continental drift and sea-floor spreading, and earthquake and tsunami safety on the BC coast.
BC Curriculum learning standard: Plate tectonics: evidence, plate boundaries, earthquakes, volcanoes and the Cascadia subduction zone
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Which plate is sliding beneath the North American plate off the coast of BC?
- the African plate
- the Juan de Fuca plate
- the Pacific plate only
- the Eurasian plate
Show answer
the Juan de Fuca plate
Hint: This subduction zone is the Cascadia Subduction Zone.
Question 2
The Queen Charlotte Fault off Haida Gwaii is a boundary where plates…
- slide sideways past each other
- sink into the core
- collide to make a mountain range
- pull apart to make a new ocean
Show answer
slide sideways past each other
Hint: It is a transform boundary between the Pacific and North American plates.
Question 3
Which type of plate boundary is it? Sort each description.
Sort into: ↔️ Divergent · ➡️⬅️ Convergent · ↕️ Transform
- 🌊new crust forms at a mid-ocean ridge
- 🌋an oceanic plate sinks under a continent
- 🏔️two continents collide to build mountains
- 🌉the San Andreas Fault
- ⚡plates grind sideways past each other
- 🏜️plates pull apart in a rift valley
Show answer
↔️ Divergent: new crust forms at a mid-ocean ridge, plates pull apart in a rift valley · ➡️⬅️ Convergent: an oceanic plate sinks under a continent, two continents collide to build mountains · ↕️ Transform: the San Andreas Fault, plates grind sideways past each other
Hint: Divergent boundaries pull apart (new crust). Convergent boundaries push together (mountains, subduction). Transform boundaries slide past each other.
Question 4
Where do deep ocean trenches form?
- In the middle of continents
- At subduction zones, where one plate sinks beneath another
- Along sandy beaches
- At mid-ocean ridges
Show answer
At subduction zones, where one plate sinks beneath another
Hint: The sinking plate bends downward and makes a deep trench.
Question 5
Alfred Wegener proposed continental drift. What evidence supported it?
- Weather maps
- Ocean tides
- Satellite photos taken in 1900
- Matching fossils and rock layers on different continents
Show answer
Matching fossils and rock layers on different continents
Hint: Similar fossils and matching coastlines suggested the continents were once joined.
Question 6
Which kind of crust is denser?
- Continental crust
- It depends on the season
- Oceanic crust
- Both are exactly the same
Show answer
Oceanic crust
Hint: Because it is denser, oceanic crust usually sinks under continental crust.