INSIDE THE EARTH

Plate Tectonics

The Composition of the EarthA. These layers describe the chemical makeup of

the Earth, the compounds found in the layersB. Crust – thinnest, outermost layer

- Made of oxygen, silicon, and aluminum1. Oceanic – more dense than continental crust2. Continental – thicker than oceanic crust

C. Mantle – middle layer (thicker than crust)- Has more magnesium, so it is more dense

than crustD. Core – inner layer (most dense layer)

- Made mostly of iron and some nickel

Facts about the layers• The crust can be as thick as 3 miles to 75 miles in size.

• No one has ever been below or even drilled below the crust.

• The center of the Earth is hotter than the surface of the Sun.

• The temperatures in the mantle range from 2000-5000 ºF

• The temperatures in the core range from 7000-12000 ºF

• The core creates the Earth’s magnetic field

Physical StructuresWe think of the Earth as having three layers;

crust, mantle and core. The Earth layers are also described in a different way.

The five physical layers include:

1. Lithosphere 2. Asthenosphere3. Mesosphere 4. Outer core

5. Inner Core

1. LithosphereA. Consists of the crust and top part of

mantle• Outermost, rigid layer

B. Made of solid rock/mineralsC. Pieces of the lithosphere are

divided into tectonic plates• Can contain both continental

and oceanic crust• Lithos is Greek for “rock”

2. AsthenosphereA. Under the Lithosphere

B. Part of the mantle

C. Made of bendable rock1. Like a marshmallow2. Still a solid but it can move and flow

D. Astheno is Greek for “weak”

3. MesosphereA. Below the Asthenosphere

B. Lower part of the mantle1. Touches the outer core

C. Made of hard strong solid rock/minerals

D. Meso is Greek for “middle”

4. Outer Core– hot, liquid layer that is between the

mesosphere and the inner core

5. Inner Core– center of the Earth– solid, metal ball– most dense layer

Mapping the Earth’s Interior•Earthquakes give us clues to what is below the crust•Seismic waves are vibrations given off when there is an earthquake

•They travel at different speeds depending on the composition

• Waves travel faster through a solid than a liquid• S waves cannot travel through liquids• P waves can travel through solids and liquids

• Seismographs are instruments that measure the time it takes for seismic waves to reach a site

Layer of Earth

Physical layer

What they are like

Lithosphere

Asthenosphere

Mesosphere

Outer Core

Inner Core

Fill in the chart using the following…

• Core• Mantle• Core• Mantle• Crust• Mantle

• Thought to be solid rock, found in middle

• Solid and very rigid (eroded/weathered rock)

• Pure liquid, very hot• Solid and dense

metal ball in center of Earth

• Hot and soft rock that flows (marshmallow)

Layer of Earth

Physical layer What they are like

Crust Lithosphere

Asthenosphere

Mantle

Core

MantleMantle

Mesosphere

Outer CoreCore

Inner Core

Solid and very rigid rock(eroded/weathered rock)Hot and soft rock that flows slowlyThought to be solid rock, found in middlePure liquid, very hot

Solid and dense metal ball in center of the Earth