Comparing the Layers of Earth S6E5.a.

Which is the outermost layer? THE CRUST Thickness - 5km – 70km thick depending on location

The Crust: What’s it made of? 2 types of crust: Oceanic – mostly basalt rocks The thinnest crust More dense than continental crust Continental – mostly granite rocks The thicker crust –less dense than Oceanic Crust

Next is the Mantle… Temp ranges from 1600 F to 6700 F Beneath the crust Thickness is 2900 km

The Mantle Made of 3 distinct areas: Lithosphere Asthenosphere Lower Mantle

Lithosphere Thickness: approx 100 km thick Located directly beneath the crust Composition: State of Matter Solid “Lithos” means “Stone” Includes the Crust Broken into large plates

Asthenosphere Thickness - 300 km Composition: Molten Material State of Matter - Semi-Solid “Asthenes” means “weak” Includes convections currents that move plates above Located right below the Lithosphere

Lower Mantle Thickness - 2500 km State of Matter Composition Solid Very hot dense rock Mg, Si, O, Fe

Outer Core Temperature = 6700 °F to 7800 °F Thickness - 2266 km Located just beneath the mantle Composition: Molten Metal (Fe & Ni) State of Matter Liquid

What makes the Outer Core unique? Creates Earth’s magnetic field - due to outer core rotating around inner core

Inner Core Temperature = 7800 °F to 13000 °F HOTTEST LAYER!!! Thickness - 1216 km Composition: Dense, solid metal ball of Fe & Ni!

What’s unique about the Inner Core? Extreme pressure squeezes the atoms of the Fe & Ni so much, they cannot spread out! Stays solid!

Seismic Waves Seismic waves – generated by earthquakes – provide this evidence. The P and S waves are recorded by stations around the world P and S waves travel more quickly through more dense material and slow down when passing through less dense material

Seismic Waves Partially molten areas slow P waves and weaken S waves S waves are completely stopped when passing through a liquid