EARTHS STRUCTURE Crust outermost layer Mantle solid near

EARTH’S STRUCTURE

ü Crust – outermost layer üMantle – solid near the crust, but flows like putty near the core üCore – has an inner and outer core

THE CRUST • The outermost layer, the crust, is made up of lightweight rocks. • 0 - 62 miles deep • Makes up about 1% of Earth’s mass • Main elements in this layer are oxygen, silicon, and aluminum.

• The are two kinds of crust: continental crust and oceanic crust. • Continental crust is lighter, older, and thicker that make up the continents • Oceanic crust is the rock that forms the ocean floor.

• The crust and upper part of the mantle form the LITHOSPHERE. • The Lithosphere is divided into TECTONIC PLATES - large sections of Earth’s crust they move slowly by floating on top of dense, partly melted rock.

• Tectonic plates drift across Earth’s surface at rates ranging from less than 2 cm to more than 15 cm per year.

THE MANTLE • • The mantle is the layer below the crust. 1800 miles thick Makes up 67% of Earth’s mass Main elements are iron, magnesium, aluminum, and silicon • The mantle is denser than the crust

• The uppermost part of mantle is solid • The middle part is more like a thick liquid • The lowest section is solid, even though its temperatures is even higher than that of the middle layers. – Pressure is so great, the solid cannot melt

THE CORE • • The Earth’s innermost layer is the core. 2200 miles thick Makes up about 32% of Earth’s mass The core is MOSTLY iron, with a little bit of nickel.

• Earth’s core consists of two parts: inner and outer cores • The outer core is liquid, but high pressure keeps the inner core solid. • The temp. at the very center of Earth is 6, 000°C or 10, 832°F • The pressure is four million times greater than the pressure at Earth’s surface • °