Untitled Lesson

Earth’s layers

Fill in the Blanks

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Crust

Uppermost layer of the Earth

2 types: oceanic and continental

This layer is a solid

Land

Ocean

Oceanic crust

Makes up the floor of the ocean -
denser than continental crust

(denser means it sinks
underneath the continental crust
where they meet)

Continental crust

Part of the Earth’s crust that
forms land

Mantle

Region of hot, slow flowing, solid
rock between the crust and the
core. 3 sublayers. All together,
around 1800 miles deep and
make up the thickest layer of the
Earth.

Upper mantle

Rigid, sits directly under Earth’s
crust

Middle mantle

Composed of soft, bendable
rocks that flow with the presence
of convection currents

Lower mantle

Semi-rigid. Hotter and denser
than the rest of the mantle

Core

Densest layer and ⅓ of Earth’s
mass. 2 sublayers!

Made of iron and nickel

Outer Core

Liquid metal, about 1400 miles
thick

Inner Core

Solid metal 800 miles thick

Even though it is the hottest
layer, the intense pressure (the
force that pushes the particles
really close together) is so strong
that the particles are able to flow
past each other. That flow
means it is a liquid!

Asthenosphere

Upper layer of the mantle

Lithosphere

Earth’s crust the outermost part
of the mantle

Solid, brittle, rigid layer broken
into tectonic plates that move
along the mantle on convection
currents

Convection currents

The tectonic plates move on
convection currents.
Convection: Heat rises, cooler
areas sink.

As rock sinks towards the center of the Earth, it gets warmer. Eventually it is warmer
than the layers that surround it, so it rises back towards the surface. This creates a
cycle of flow that pushes the plates.

Red: Warm; Blue: cool