The Earth’s Layers

Standard: Regions of different continents share similar fossils and similar rocks, which suggest that in the past those sections of continents were once joined and have since separated.

The Earth is divided into four layers.

Crust The crust is the outer most layer followed by the lithosphere (also solid rock).

Crust continental crust and oceanic crust. Is the thinnest layer and less dense than other layers. It is composed of two rocks: continental crust and oceanic crust. Composed of granite, less dense. 25 miles thick Composed of basalt, very dense 3-5 miles thick Lithosphere

Mantle (located below crust) The mantle is the largest layer of the Earth. Consist of liquid rock Composed of magnesium and iron. Increase in pressure & density

Mantle The movement in the mantle (convection currents) create the movement of the Earth’s plates.

Cooler liquid, more dense Hotter liquid, less dense Convection Currents Caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again. The currents occur in the asthenosphere and move the crust. Cooler liquid, more dense Hotter liquid, less dense

Occurs in liquids and gases. Convection Current Occurs in liquids and gases. Hot is less dense Cold is more dense

Lithosphere Plates

Core (outer) The outer core is composed of liquid metals: nickel & iron. 1400 miles thick

Core (inner) Heaviest Layer Temperatures so HOT and an increased amount of pressure that the metals (iron and nickel) are squeezed together and cannot move like a liquid, but are forced to vibrate and become SOLID! Heaviest Layer

Today’s Assessment Question Topic: Convection Currents Assignment: Can you illustrate any example of a convection current? Be sure to label your illustration.