Inside the Earth

There are 2 ways to divide the layers of the earth..... Physical layers Compositional layers

Earth’s Interior Earth’s interior is divided into layers: the crust, mantle, & core, based on composition. Although the Earth’s crust seem stable, the extreme heat of the Earth’s interior causes changes that slowly reshape the surface.

Composition Layers Crust Mantle Core

The Crust Outermost layer of earth made of rock that forms earth’s outer skin 5 to 100 km thick, average thickness is 35 km thinnest layer less than 1% of Earth’s mass Most of composition of crust: oxygen, silicon, and aluminum

The Crust Oceanic Crust Continental Crust crust beneath the oceans consist mainly of dense rock (basalt - dark in color) 5-8 km thick Continental Crust crust that forms the continents consist mainly of less dense rock (granite - lighter in color) 30 km average thickness

The Mantle layer of rock between crust and core 2900km thick, 67% of Earth’s mass Magma from volcanoes comes from mantle Composition - silicon, oxygen, iron and magnesium physical conditions in mantle change because pressure and temperature increase with depth temp ranges from 870 ºC to 2,200ºC

What happens in the Mantle? Convections Currents! Hot columns of mantle material rise slowly through the asthenosphere

The Core Innermost layer of the Earth 6800 km in diameter (3,400 km from outside edge of core to center of core) 1/3 of Earth’s mass, 15% of its volume Temperature ranges from 2,000 ºC to 5,000ºC Consist of 2 parts; Inner Core and Outer Core

Physical Layers

Lithosphere The upper part of the mantle (upper part does not flow like the lower part) and the crust together form a rigid layer called the lithosphere. Lithos is greek for stone, 100 km thick Made of tectonic plates

Asthenosphere The asthenosphere is a soft layer of the mantle on which pieces of the lithosphere move. 250 km thick asthenes is Greek for soft or weak Rock that is semi solid, plasticky, kind of the consistency of peanut butter. Heat travels by convection currents

Mesosphere The mesosphere is located in the lower mantle. It is completely solid 2,550 km thick

Outer Core/Inner Core Outer Core Inner Core layer of molten metal (iron and nickel) beneath the mantle surrounds the inner core 2,200 km thick Inner Core dense ball of solid metal (iron and nickel) extreme pressure from layers above 1200 km, from outside edge of inner core to center

Tectonic Plates The tectonic plates are pieces of the lithosphere that fit like pieces of a jigsaw puzzle and move on top of the asthenosphere May Consist of both Continental and Oceanic Crust

Density and Earth Layers Atmosphere: .001g/cm^3 Water: 1.0g/cm^3 Crust: 2.7-3.0 g/cm^3 Mantle: 3-9 g/cm^3 Core: 9-13 g/cm^3

How do scientists know about the inside of the earth? Seismic waves

The End