Topic 4: Layers of the Earth

Earth

_____ is known to be the only planet in the universe that sustains life. While it may appear to be one huge solid rock, it is actually made up of various components, some of which are constantly shifting and moving.

4

Earth's structure is made up of how many different layers? Each layer has its distinct characteristics and composition.

Crust

The Earth's outermost layer is known as the crust. It is where life exists.

Crust

Location: Outermost layer

Crust

Composition: Solid rocks (granite, basalt)

Crust

Types: Oceanic ______ (thin, dense) & Continental _____ (thicker, less dense)

Crust

Temperature: Up to 400°C

Mantle

Made of molten iron and minerals that will still flow under pressure.

Mantle

Composition: Silicate minerals rich in magnesium and iron

Mantle

Divisions: Upper ______ & lower ______

Mantle

Behavior: Solid but flows slowly (asthenosphere)

Mantle

Temperature: Up to 4,000°C

Outercore

Location: Lies beneath the mantle and surrounds the inner core.

Outercore

State: Liquid

Outercore

Composition: Primarily iron and nickel

Outercore

Thickness: About 2,200 kilometers

Outercore

Temperature: Around 4,000°C to 6,000°C

Outer Core

Key Feature: The movement of liquid metal in the outer core generates Earth’s magnetic field through a process called the geodynamo.

Inner Core

Location: Center of the Earth

Inner Core

State: Solid (despite high temperature, due to immense pressure)

Inner Core

Composition: Mostly iron and some nickel

Inner Core

Radius: About 1,200 kilometers

Inner Core

Temperature: Up to 6,000°C—comparable to the surface of the Sun

Inner Core

Key Feature: Extremely dense and under enormous pressure; believed to slowly rotate at a different rate than the rest of the planet.