Social Sciences and History / Unit 10 SSH 0917 short lesson, about 20 seconds
Crust, Mantle, Core
Captions available
The idea
Earth is an oblate spheroid, flattened at the poles and bulging at the equator. Chemically it has three layers: crust, mantle, core. The crust comes in two kinds: continental, low density and granite-like; oceanic, higher density and basalt-like, especially when cold and old.
In practice
Knowledge from seismic waves and meteorites.
Where people slip
Chemical layers and physical layers are two different cuts.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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