Earth's Layers and Plate Tectonics Quiz

Grade 5 · Science · Quiz

Test your knowledge of Earth's interior layers and the tectonic forces that shape our planet.

Questions

Which layer of Earth is the thickest?
1. Crust
2. Inner core
3. Mantle
4. Outer core
Show answer
Answer: Mantle
The mantle extends from about 70 km to 2,900 km depth — making it by far the thickest layer at about 2,900 km thick.
The Himalayas formed at a convergent boundary where two continental plates collided.
Show answer
Answer: True
The Indian Plate collided with the Eurasian Plate about 50 million years ago. Both plates are continental, so neither subducted — instead they buckled upward into the Himalayas.
The liquid layer of Earth's core is called the ___ core.
Show answer
Answer: outer
The outer core (2,900-5,150 km deep) is liquid molten iron and nickel. Its circulation generates Earth's magnetic field. The inner core is solid despite being hotter.
What evidence supports the theory that the continents were once joined?
1. All oceans have the same salt content
2. Matching fossils found on now-separated continents
3. All mountains are the same height
4. Ocean water is the same temperature everywhere
Show answer
Answer: Matching fossils found on now-separated continents
Identical fossils of the freshwater reptile Mesosaurus and the land plant Glossopteris found in Brazil AND South Africa are compelling evidence that these continents were once connected.
Earthquakes are most common in the middle of tectonic plates, far from boundaries.
Show answer
Answer: False
Most earthquakes and volcanic activity occur at plate boundaries. The middle of plates (called cratons) are typically geologically stable.
What happens at a transform plate boundary?
1. Plates collide and form mountains
2. Plates pull apart and form new crust
3. Plates slide past each other horizontally
4. One plate dives beneath another
Show answer
Answer: Plates slide past each other horizontally
At transform boundaries, plates grind horizontally past each other. The San Andreas Fault in California is a famous transform boundary where the Pacific and North American plates slide past each other.
The layer directly below Earth's crust is called the ___.
Show answer
Answer: mantle
The mantle begins directly below the crust (at the Moho discontinuity) and extends 2,900 km deep. It's solid rock that flows extremely slowly due to heat and pressure.
Which feature is formed when an oceanic plate dives beneath a continental plate?
1. Mountain range
2. Rift valley
3. Volcanic arc
4. Plateau
Show answer
Answer: Volcanic arc
When an oceanic plate dives beneath (subducts) a continental plate, the oceanic plate melts as it goes deeper. Magma rises through the continental plate, creating a chain of volcanoes.
Continental crust is thicker than oceanic crust.
Show answer
Answer: True
Continental crust is 25-70 km thick (mostly less-dense granite). Oceanic crust is only 5-10 km thick but is denser (basalt), which is why it subducts when colliding with continental crust.
Earth's magnetic field is generated by:
1. Rotation of the crust
2. Movement of molten iron in the outer core
3. Heat from the inner core
4. The mantle's slow flow
Show answer
Answer: Movement of molten iron in the outer core
Convection currents of molten iron in the outer core create electrical currents, which generate Earth's magnetic field through a process called the geodynamo.

Get a personalized course on Earth's Layers and Plate Tectonics built around your child.