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

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

3. 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.

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

5. 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

6. 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

7. 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.

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

9. 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.

10. 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.

11. 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.

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

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

14. 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

15. 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.

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

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

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

19. 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