Layers of the Earth Notes

Earth’s Layers Earth is divided into layers 2 different ways Composition What it’s made of Physical properties What can be observed/doesn’t change chemical properties Crust

Earth’s Layers by Composition Crust Core Mantle Core

Earth’s Layers by Composition Crust Outermost layer Thinnest layer Composed mostly of oxygen, silicon, and aluminum Two types Oceanic (found under oceans; more dense) Twice as much iron, calcium, and magnesium which are more dense minerals Continental (found under land; less dense)

Earth’s Layers by Composition Mantle Between the crust and core Much thicker than crust Composed of more magnesium and less aluminum and silicon than the crust so it is more dense than the crust

Earth’s Layers by Composition Core Below the mantle; at the center of Earth Makes up 1/3 of Earth’s mass Composed primarily of iron and nickel Almost no oxygen, silicon, aluminum, or magnesium Heats the mantle by convection

Earth’s Layers by Physical Properties Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

Earth’s Layers by Physical Properties Lithosphere Solid, outermost part of Earth Includes crust and rigid upper part of mantle Divided into pieces called tectonic (or lithospheric) plates

Earth’s Layers by Physical Properties Asthenosphere Found directly under the lithosphere Tectonic (lithospheric) plates move on this layer Made of solid rock that flows slowly

Earth’s Layers by Physical Properties Mesosphere Found directly under the asthenosphere Lowest part of the mantle Very strong

Earth’s Layers by Physical Properties Outer Core Found beneath the mesosphere Liquid layer of Earth’s core Surrounds inner core Made of iron and nickel Heats the mantle by convection

Earth’s Layers by Physical Properties Inner Core Found beneath the outer core Solid layer of Earth’s core Very dense Made of iron and nickel

Earth’s Magnetic Properties Earth acts like a giant magnet Earth (like any manufactured magnet) exhibits 2 poles North South Earth’s outer core spins as Earth rotates This creates the magnetic field

Compass A compass is composed of a small, light-weight magnet (called a needle) Balances on a point One pole of the magnet will be attracted and point toward the Earth’s North Pole This pole on the magnet is called the north pole of the magnet Compasses are used for navigation from any point on Earth’s surface Possible because of Earth’s magnetic field

Layers of Earth Comparisons PHYSICAL PROPERTIES COMPOSITION Crust Lithosphere Mesosphere Mantle Asthenosphere Core Outer Core Inner Core

Layers of Earth Comparisons Crust PHYSICAL PROPERTIES COMPOSITION Lithosphere Mesosphere Mantle Asthenosphere Core Outer Core Inner Core

Layers of Earth Comparisons