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11/26/14 INSIDE THE EARTH EARTH Made of up several layers Studied in two ways: Composition (elements) Physical properties (temperature, density) Three Physical layers Crust (least dense material) Mantle Core (most dense material) CHEMICAL LAYERS OF EARTH Properties include temperature, density, and ability to flow Five layers: Lithosphere Asthenosphere Mesosphere Outer Core Inner Core LITHOSPHERE Outermost, rigid layer Two parts “Rock sphere” Crust Rigid upper part of mantle Divided into pieces called tectonic plates ASTHENOSPHERE Soft layer of mantle Solid rock that flows very slowly (like putty) “Weak sphere” About same rate that your fingernails grow Pieces of lithosphere move on top of this layer MESOSPHERE Strong, lower part of mantle “Middle sphere” Extends from bottom of asthenosphere down to Earth’s core Differences in density and rigidity from asthenosphere OUTER CORE Liquid layer Lies beneath mantle and surrounds inner core Temperature range from 4,400 to 5,100 °C INNER CORE Solid, dense center of planet Bottom of outer core to center of planet Temperature ranges from 5,100 to 6,200 °C Discovered through use of earthquake generated seismic waves Outer Inner Convection of liquid metal results in Earth’s magnetic field OUTER AND INNER CORE THE CRUST Outermost layer Thinnest layer also Two types of crust: Continental (granite-like) Oceanic crust (basalt-like) Denser than continental Layer we know most about THE MANTLE Layer between crust and core Extremely thick Contains most of Earth’s mass Too deep to drill to Underwater volcanoes serve as “windows” THE CORE Layer below the mantle to center of Earth Composed mostly of iron (Fe) and smaller amounts of nickel (Ni) Makes up about 33% of Earth’s mass