1. Review….
Density of Earth Lab What planet is the most dense? What planet is the least dense? **Name some earth systems that are driven by density differences

2. Earth from the Inside Out
What’s on the Inside?

3. Earth Basics 3rd planet from the Sun Oblate spheroid (slightly flat)
Circumference approx. 40,000 km
Diameter 12,756 km.

4. Earth’s Layers Inner core: Solid iron & nickel 7,200 °C +
Heat from radioactive decay
Outer core:
Liquid Iron & nickel
4,300 °C
Mantle:
Dense, hot layer of semi-solid rock (iron, magnesium, and calcium )
3,700 °C.
Crust
Silicate rock materials
One % of the earth
Lower boundary - Mohorovicic discontinuity (Moho)
Asthenosphere – lower, plasticy part
Lithosphere – top, solid part

5. Evidence for Earth’s Layers?
1. 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

6. 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
What does the chart tell us about Earth’s interior?

7. 2. Evidence from Meteorites
Leftovers & 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 to the three types of meteorites!

8. 3. Volcanoes Provide Some Evidence
Transports materials from upper mantle to surface
Doesn’t provide information about deep layers

9. 4. Magnetosphere as Evidence
Earth’s liquid, metallic outer core spins
Spin creates magnetic field
Magnetosphere protects Earth from solar wind

10. Transfer of Heat from Core
Remember what heat is?
Heat:
a form of Energy
Vibration of atoms & molecules
Greater energy = faster vibration = more heat
Heat moves in 3 ways:
Conduction
Convection
Radiation
SCIENCE MUSIC!
Conduction, Convection, Radiation!

11. Convection: Transfer of 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 Heat transfer is transfer of energy

12. Convection Moves Earth’s Crust
Crust is broken into “plates”
Convection in Mantle moves crust
Changes Earth’s surface slowly over time

13. Activity: Convection Mini-Lab

14. 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

15. Something to Think About:
Match each of Earth’s Layers:
Inner Core
Outer Core
Mantle
Crust