Lesson E1 ~ The Layers of the Earth Science 8 Lesson E1 ~ The Layers of the Earth

Layers of the Earth The Earth is composed of four different layers The crust The mantle The inner core The outer core

The Crust The crust is the solid surface on the outside of the planet It ranges from 5 to 100 km thick The crust has temperature ranging from 5°C to 1000°C The crust is less dense than the deeper layers of the Earth; this allows the crust to float on top of the mantle

The Crust

The Mantle The mantle is the partly melted layer below the crust The mantle is ~2900 km thick and ranges from 1000ºC to 2500 ºC The upper mantle flows like chewy caramel; the lower mantle doesn’t flow The deeper you go, the denser the mantle gets because of the pressure of the layers above

The Mantle

The Core The core is divided into two layers: The outer core The inner core

The Outer Core The outer core is ~2200 km thick and the temperature increases from 4000°C to 5500°C It is an extremely dense liquid layer composed mostly of iron and nickel The outer core’s outer layer flows

The Inner Core The inner core is the middle of the Earth It is almost as hot as the surface of the sun, but kept solid by the pressure It is ~1250 km thick It has a temperature of ~6000ºC Composed of primarily iron

Earthquake Evidence for Earth’s Structure One piece of evidence for the structure of the Earth is the movement of P & S waves The time that seismic waves arrive at distant points doesn’t work for a uniform Earth

Layers of the Atmosphere (Above the Earth)

Summary of the Earth’s Layers The Earth has four layers: The crust The mantle The outer core The inner core Each layer has a different temperature, thickness, and composition