2. Friday 1-25 ps Intro to earth Science

4. Earth Science? Geology Meteorology Oceanography Hydrology Seismology Ecology

5. Definitions Earth Science is the study of the earth, how it functions and the connections to the life that lives or has lived on it Meteorology – atmosphere Oceanography/Hydrology- water Seismology- inside the earth Ecology- relationship between life and its environment

6. Our focus Overview of the science Connection to physical concepts History of the Earth

7. Statistics about the Earth Shape of Earth is an oblate spheroid (only just 40 miles difference in circumferences) Circumference is about 24,000 miles around Radius is about 3800 miles Diameter 7600 miles

8. Distance between New York and Los Angeles is 2400 miles Trip = 1/10 around the world = 2/3 to the center of the earth

9. Earth facts Relatively smooth for the scale Highest mountains are 5.5 miles from sea level Deepest trenches about 7 miles below sea level

10. Facts of Earth 71 % of Earth is covered by water 97% of that water is salty Air we breathe at this point in earth’s history is made up of 78% nitrogen 21 % oxygen 1% other gases (including CD)

11. The Pacific ocean Largest ocean at present 64 million square Miles It would take 244 States of Texas To cover the same area

12. Trash in the ocean

13. How old is the Earth? a)About 7000 years b)About 4.5 million years c)About 180 million years d)About 1.8 billion years e)About 4.5 billion years

14. Explanation A)age derived from calculations based on info from the Bible B)Age of the first species that could be considered human C)Last time that Africa was attached to North America D)First time that multicellular life emerged E)Time of the formation of Earth

15. How many lifetimes could a normal modern American have lived since the formation of the Earth? About 60 million lifetimes

16. Change is the only constant in the history of Earth 65 million years ago, the ancestor of the modern whale walked the Earth looking more like a dog than a whale

17. How hot is the Earth? Up to 140° FDown to -100°F

18. Black Smoker Vent at the bottom of the ocean (500°F)

19. Inside the earth? Deepest that man has traveled into the earth? A couple of miles down in the gold mines of South Africa 1 degree for every 33 m Without air conditioning it would be around 160- 170°F With air conditioning it is 100 degrees with a 100% humidity

20. South African Gold Miner

21. Deeper into the earth About 20-40 km down = 350 ° F, the temperature you bake a cake About 1000-1200 miles down = 2300 ° F At the center of the Earth = up to 11,000 °F In other words, 110 times more hot than the hottest summer day you have ever experienced

22. Scale is different in this portion of the class than before

23. Cross section of the earth Inner core Outer Core Mantle Asthenosphere Lithosphere Crust Hydrosphere Atmosphere Magnetosphere

24. Inner Core Solid Metal, nickel and iron Under incredible temp and pressure Pressure keeps it solid Around 1000 mile thick in diameter

25. Outer core Same composition as the inner core Less heat and pressure Liquid The movement of the Iron liquid, generates the Earth’s magnetic field Slightly thicker than inner core The volume occupied by both cores is about 29.5% of the Earth’s total

26. Mantle Thickest section of the interior of the earth The entire mantle Comprises 80% of Earth volume The top of the mantle is further divided into 2 important subsections –Lithosphere –Asthenosphere

27. Mantle subsections Lithosphere topmost layer of mantle (nearest to surface of Earth) solid, brittle Asthenosphere underlies the lithosphere texture like silly-putty, bends under pressure

28. Crust The layer of the earth next to the surface Very thin –Oceanic 2-4 miles –Continental 40-65 miles The least dense of all layers –Ocean crust is denser than continental crust We have never drilled all the way through the crust

29. The Moho The boundary between the crust and the lithosphere

30. How do you think we know anything about the inside the earth?

31. Different form of Echolocation Using seismic waves Created by vibrations of the Earth Using time to indicate distance and type of material Causes of vibration Natural: Earthquakes Man-made: Gunshots

32. Using an air-gun to create seismic waves

33. A cross sectional map using info from seismic waves

34. Two types of Seismic waves used P-waves Primary-pressure wave (longitudinal) Fastest wave Some of the wave goes through all material, some reflects back Changes direction at each boundary

35. S-waves Secondary, shear Slower than P-waves Can not go through liquid

36. Info from Seismic waves Can tell the texture of the rock through interpretation of the speed of seismic waves Seismic waves move faster in more dense material The s-waves can not travel thru any liquid

37. Seismic wave speed Faster in lithosphere than crust Slows down in Asthenosphere Increases through the rest of the mantle Drops off in Outer Core No S waves

38. Shadow Zone

39. Magnetosphere The range of Earth’s magnetic field Extends beyond the atmosphere into space Northern lights May be caused by the movement of the Earth’s liquid core

40. There may be another source of magnetic field Both Sun and Moon have magnetic fields Sun contains very little iron Moon does not have a liquid core

43. Northern Lights Aurora Borealis Result from the interaction between the -Solar wind (charged particles expelled from the outer edge of the sun) -Earth’s magnetosphere -Earth’s Atmosphere Best seen in winter (less water vapor in air) at the poles

44. Fig. 12-26, pg. 356