The Three Layers of the Earth Quiz

15 Questions

What is the lithosphere made of?

Lower portion of the crust and uppermost part of the mantle

What causes the creation of mountains?

Slow movement of tectonic plates due to convection currents in the mantle

What are tectonic plates made of?

Thick pieces of lithosphere including oceanic and continental crust

What scientific principle causes the different layers of the Earth?

Gravity

What refers to the line between tectonic plates that sees geological activity when they move?

Fault line

What are the three main rocky layers of the Earth?

Crust, Mantle, Core

Which layer of the Earth consists of a semi-solid magma layer?

Mantle

What is the composition of the Earth's core?

Solid mass of metal (inner core) and a liquid mass of iron and nickel (outer core)

Why is it difficult to answer how many layers make up the Earth?

Each main layer can be seen to have sub-layers

What makes up the outer layer of the Earth on which humans and animals live and plants grow?

Crust

What is the primary composition of the Earth's core?

Iron and nickel

At what depth does the mantle's asthenosphere start?

60 miles below the surface

What causes the Earth's magnetic field?

Liquid outer core made of iron and nickel

Which layer of the Earth is considered to be a solid plasma by some scientists?

Inner core

Where is the Earth's crust thickest?

Bottom of the ocean

Study Notes

The Earth is made up of multiple layers, including rocky layers and atmospheric layers. This summary focuses on the rocky layers.
The Earth's core consists of a solid inner core and a liquid outer core. Both are primarily composed of iron and nickel.
- Inner core: Extremely hot (over 9000 degrees F) and under immense pressure (up to 3.6 million atmospheres), keeping it in a solid state. Some scientists consider it a solid plasma.
- Outer core: Liquid, made up of iron and nickel, and under less pressure than the inner core, causing it to be in a liquid state. Generates Earth's magnetic field.
The mantle is the largest layer, making up about 84% of the Earth's total volume. It starts about 20 miles below the surface and extends approximately 1800 miles towards the core.
- Asthenosphere: Uppermost layer, about 60 miles below the surface, behaves like a convection oven with molten magma, causes earthquakes and volcanic activity.
- Central mantle/transition zone: Rocks transform into denser forms, extends from 250 to 410 miles below the surface, holds as much water as Earth's oceans.
- Lower mantle: Hottest and densest layer, starts about 410 miles below the surface, more solid than other layers due to increased pressure.
The Earth's crust is the thinnest layer, supporting all life and is solid but brittle. It is about 20 miles thick on average, thinnest at the bottom of the ocean, and thickest at mountain tops.