1. Earth as a System: Earth: A Unique Planet 2.1 and 2.2 Page 27

2. Unique facts Only planet with liquid water on the surface Atmosphere has a large percentage of oxygen Only planet to support life

3. Earth basics Third planet from the sun 4.6 billion years old Mostly made of rock 71% covered with liquid water

4. Earth from Space A blue sphere with white clouds It is an oblate spheroid Spinning made the polar regions flatten and have an equatorial bulge Relatively smooth

5. You have five minutes to read 2.1 page 27-30

6. Earth’s Interior Seismic waves have shown that Earth’s interior is layered

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8. Layers of the Earth Earlier you learned about crust, mantle, and core

9. Here are some new terms Look over only

10. Old TermsNew Terms Crust Mantle Core Outer Inner Lithosphere Crust and upper solid mantle Asthenosphere Flows with plasticity Mesosphere Strong lower part of the mantle Core Outer Inner

12. Compositional &Structural Zones The Earth’s interior can be divided into compositional and structural zones. Compositional—What they are made of Structural—how they behave

13. Compositional zones are Crust Mantle Core

14. Structural Zones Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

15. Compositional layers Crust thin, solid, uppermost zone of Earth. Crust thin, solid, uppermost zone of Earth. The crust varies from thin on the ocean floor to thick at the mountain ranges

16. The crust is 10km thick under the oceans Made of basalt Continental crust is between 20-60 km thick Made of granitic rocks that are less dense than basalt

17. Crust Thickness

18. The crust is the uppermost part of the lithosphere

19. Earth's Internal Layers Andrija Mohorovičić studied seismograms and discovered waves pick up speed at a certain depth Earth is layered Drew a map of the upper boundary of Earth's mantle, Mohorovičić discontinuity

20. Cool geologists call it the

21. The Mantle 3000 kilometers thick 2/3 of Earth’s mass Hot iron-rich silicate rocks

22. Core The center of the Earth Made of iron and nickel

23. Structural Zones

24. Lithosphere Narrow layer Includes the Crust and Upper Mantle The Upper Mantle is cool and brittle

25. The lithosphere is very narrow and is rigid and brittle. It floats on the asthenosphere. The lithosphere is less dense

26. Asthenosphere Below the lithosphere is a less rigid layer called the asthenosphere It is made of hot, iron-rich silicate rocks Because of the intense heat and pressure it behaves with plasticity It is a solid that flows like a liquid

27. Thermal convection currents occur here

28. Convection currents: hot less dense material rises, cools, and begins to fall again.

29. Mesosphere The strong lower part of the mantle Literally –the middle sphere Lies between the asthenosphere and outer core

30. The core is still the core.

31. The core has two parts: the inner and outer cores Outer core: liquid iron and nickel Inner core: Solid iron, nickel, & sulfur

32. Magnetic Field When a magnetic material rotates with another magnetic material an electric current is generated This current generates an electric field

33. The Earth's inner core spins within the liquid outer core producing a magnetic field

35. Magnetosphere

36. Earth’s Gravity Gravity is the force of attraction that exists between all matter in the universe Newton described his Universal Law of Gravitation The force of attraction between any two objects depend on both their mass and the distance between them

37. Weight and Mass Weight is the measure of the strength of the pull on an object (a measure of gravitational force) Mass is the amount of matter in an object There is a difference Mass stays the same, weight varies depending on where you are

38. An object’s weight depends on its mass and its distance from the center of the Earth According to the law of gravitation, the force of gravity decreases as the distance from the Earth’s center increases