How the Layers Formed As earth formed, it was made of hot molten magma and intense gravity. As rocks melted, denser materials sank to the center of the Earth and became the core. Less dense material rose to the surface and became the crust The middle layer is the mantle. – (formation of the Earth, 10 min) As earth formed, it was made of hot molten magma and intense gravity. As rocks melted, denser materials sank to the center of the Earth and became the core. Less dense material rose to the surface and became the crust The middle layer is the mantle. – (formation of the Earth, 10 min)

Lithosphere (aka Crust) A layer of solid rock that includes both dry land and the ocean floor. –Very thin compared to the other layers, like the skin of an apple. –Thickest under high mountains, thinnest under the ocean floor. –5-100 km thick –Oceanic crust is denser than continental. A layer of solid rock that includes both dry land and the ocean floor. –Very thin compared to the other layers, like the skin of an apple. –Thickest under high mountains, thinnest under the ocean floor. –5-100 km thick –Oceanic crust is denser than continental.

The Mantle Made of very hot rock. –Mixture of solid AND liquid! So cool. –Asthenosphere: Upper mantle Spelling - As The No Sphere Moves tectonic plates –Mesosphere: lower mantle that extends to the core. Made of very hot rock. –Mixture of solid AND liquid! So cool. –Asthenosphere: Upper mantle Spelling - As The No Sphere Moves tectonic plates –Mesosphere: lower mantle that extends to the core.

The Core Outer core: –molten (liquid) metal. –Movements in this part of the core causes Earth’s magnetic field. Inner core: –dense ball of solid metal. Both are made of iron and nickel, but the extreme pressure in the inner core keeps the metal a solid Outer core: –molten (liquid) metal. –Movements in this part of the core causes Earth’s magnetic field. Inner core: –dense ball of solid metal. Both are made of iron and nickel, but the extreme pressure in the inner core keeps the metal a solid

Earth’s Interior The composition and properties of Earth’s interior are identified by the behavior of seismic (earthquake) waves. (formation of the earth video, 5 min) The composition and properties of Earth’s interior are identified by the behavior of seismic (earthquake) waves. (formation of the earth video, 5 min)