11/26/14 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) Properties include temperature, density, and ability to flow Five layers: Lithosphere Asthenosphere Mesosphere Outer Core Inner Core Outermost, rigid layer Rock sphere Two parts Crust Rigid upper part of mantle Divided into pieces called tectonic plates Soft layer of mantle Weak sphere Solid rock that flows very slowly (like putty) About same rate that your fingernails grow Pieces of lithosphere move on top of this layer Strong, lower part of mantle Middle sphere Extends from bottom of asthenosphere down to Earths core Differences in density and rigidity from asthenosphere OUTER COREINNER CORE Liquid layer Lies beneath mantle and surrounds inner core Temperature range from 4,400 to 5,100 C Outer Inner Convection of liquid metal results in Earths magnetic field 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 Outermost layer Thinnest layer also Two types of crust: Continental (granite-like) Oceanic crust (basalt-like) Denser than continental Layer we know most about Layer between crust and core Extremely thick Contains most of Earths mass Too deep to drill to Underwater volcanoes serve as windows Layer below the mantle to center of Earth Composed mostly of iron (Fe) and smaller amounts of nickel (Ni) Makes up about 33% of Earths mass