1. 8th Grade Dynamic Earth U4L1 Earth’s Layers

2. Earth’s Compositional Layers
Crust
Outermost, solid layer
Made of oxygen, silicon, aluminum
2 types – continental and oceanic
Ocean has twice as much iron, calcium and magnesium
Oceanic is denser than continental, but continental is thicker
Mantle
Between core and crust
Hot, flowing, solid rock
Denser than crust
More magnesium, less aluminum and silicon than crust
Convection currents
Cooler rock sinks, warmer rock rises
Core
From below mantle to center of earth
Made mostly of iron and some nickel
Densest layer – 1/3 earth’s mass
Less oxygen, silicon, magnesium and aluminum than mantle
*3 layers based on chemical composition – crust, mantle and core
*Layers made of different mixtures of chemicals
Deepest Hole on Earth (Sci Show)-

3. Earth’s Physical Layers
Divided by physical properties including – solid / liquid, how layer moves, how layer transmits waves
Lithosphere
Outermost, rigid
Made of crust and rigid part of mantle
Divided into tectonic plates
Asthenospheres
Weak/soft mantle
Rock
Flows slowly
Tectonic plates float on top
Mesosphere
Strong lower part of mantle
Flows more slowly than asthenosphere
Outer core
Liquid (molten metal!)
Beneath mantle, surrounds inner core
Inner core
Solid, densest
Goes from bottom of outer core to center – center is 6,380 km beneath surface!
NOVA scienceNOW | NOVA Short | Journey Through the Center of the Earth (Neil DeGrasse Tyson) -