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