DO NOW Get out your notes from yesterday – “Origin of Our Solar System”. Get out Review #1 that was homework.

REVIEW…. Why did the terrestrial planets form close to the Sun while the gas giants formed farther out?

EARTH FROM THE INSIDE OUT SES1a: Describe the early evolution of the Earth and solar system, including the formation of Earth’s solid layers (core, mantle, crust), the distribution of major elements, the origin of internal heat sources, and the mechanism by which heat transfer drives plate tectonics.

EARTH BASICS 3rd planet from the Sun. Oblate spheroid (slightly flat). Circumference about 40,000 km. Diameter 12,756 km.

TERRESTRIAL WORLDS Differentiation: outer layers compress inner layers – produce heat Dense metals sink to core Iron density 7.86 g/cm3 Lighter rock material rises to form crust Average rock density 3.5 g/cm3

PROCESS OF DIFFERENTIATION – METALLIC MATERIALS SINK EARTH’S LAYERS PROCESS OF DIFFERENTIATION – METALLIC MATERIALS SINK Inner core: Solid iron and nickel 7,200 °C+ Heat from radioactive decay Outer core: Liquid Iron and nickel 4,300 °C

EARTH’S LAYERS Mantle: Dense, hot layer of semi-solid rock (iron, magnesium, and calcium ). 3,700 °C. Crust: Silicate rock materials. One percent of the earth.

EARTH’S LAYERS Crust Lower boundary - Mohorovicic discontinuity (Moho) Asthenosphere – lower, plasticy part Lithosphere – top, solid part

EVIDENCE FOR EARTH’S LAYERS One: Seismic waves Caused by either by earthquakes or by massive man-made explosions. Measured as they pass through the Earth. When they encounter different materials, they change in important ways, becoming longer, shorter, faster, or slower.

SEISMIC WAVES AS EVIDENCE Waves travel through different materials at different speeds. P (primary) waves slow down in liquids. S (secondary) waves can only travel through solids.

EVIDENCE FOR EARTH’S LAYERS Two: Meteorites Leftovers and pieces of other worlds. Three types: Chondrites (Stony-Iron) – mixed rocky & metal materials Stony – lighter, rock materials Iron - metals, mostly iron and nickel Composition of Earth believed to be similar.

EVIDENCE FOR EARTH’S LAYERS Three: Volcanoes They transport materials from upper mantle to surface. They do not provide information about deep layers.

EVIDENCE FOR EARTH’S LAYERS Four: Magnetosphere Earth’s liquid, metallic outer core spins. Spin creates magnetic field. Magnetosphere protects Earth from solar wind.

TRANSFER OF HEAT FROM CORE Remember what heat is? Heat: a form of energy Vibration of atoms and molecules Greater energy = faster vibration = more heat Heat moves in three ways: Conduction – direct contact Convection – travels in currents Radiation – travels through space

CONVECTION: TRANSFER OF HEAT ENERGY Heated material near core becomes less dense and rises. Cool material near crust is cooler and sinks. Movement of heated material from core to crust is process called convection.

DEMO Red dye is over the not part and blue dye is over the ice.

CONVECTION: MOVES EARTH’S CRUST Crust is broken into “plates”. Convection currents in mantle moves crust. Changes Earth’s surface slowly over time.

SOMETHING TO THINK ABOUT: Match each of Earth’s Layers: Inner Core Outer Core Mantle Crust D B C A

REVIEW Convection in the mantle is responsible for what process on the surface shown in the diagram? A. Plate Tectonics B. Radioactive Decay C. Conduction D. Formation of the Magnetosphere