Earth's Shape

1. Earth's Shape

2. Is the Earth flat?

3. Square?

5. A. Is the Earth a perfect sphere? • The Earth’s true shape is an oblate spheroid • It is slightly flattened at the poles and slightly bulging at the equator.

6. However, if drawn to scale, it looks like a perfect sphere!

7. There is only a 42 km difference between the polar diameter and equatorial diameter !

8. Which diagram represents the best shape of the Earth to scale? B A C D

9. If the altitude of Polaris equals the latitude of the observer, then answer the following question!!!! This question may require the use of the Earth Science Reference Tables. To an observer in Buffalo, New York, the North Star, Polaris, is always located above the northern horizon at an altitude of approximately 23½° 43° 66½° 90°

11. If the altitude of Polaris equals the latitude of the observer, then answer the following question!!!! This question may require the use of the Earth Science Reference Tables. To an observer in Buffalo, New York, the North Star, Polaris, is always located above the northern horizon at an altitude of approximately 23½° 43° 66½° 90°

12. B. Evidence of Earth's Shape

13. 1. Photographs of Earth taken from Space Best Evidence!

15. 2. As ships sail away from an observer, they drop below line of sight

17. 3. The shape of Earth’s shadow during an eclipse

18. 4.How would a weight measurement prove Earth’s shape? You would weigh more at the poles since you are closer to the center of the Earth. You would weigh less at the equator since you are farther from the center of the Earth.

19. 5. Polaris (North Star) • The North Star is located directly above Earth’s axis

21. POLARIS

22. Therefore, the altitude of Polaris = the latitude of the observer! • This method of navigation can only be used in the Northern Hemisphere.

23. If you wanted to find Polaris tonight you would have to look towards the NORTH about half-way up in the sky (42o) since we are at latitude 42oN.

24. What direction would you look to find Polaris if you were somewhere in the southern hemisphere?????

26. Astrolabe

28. Star Trails around Polaris West East

35. About the Earth

39. C. Parts of the Earth: • Lithosphere – solid crust and rigid mantle

40. Parts of the Lithosphere: • Continental Crust – thick/less dense/light color/granite • Oceanic Crust – thin/more dense/dark color/basalt

42. Hydrosphere • The water on the Earth • Covers 75% of crust

44. Atmosphere • The air (gases) that we breathe • Air is made up of mostly Nitrogen (78%) and Oxygen (21%)

45. Gases that make up our Atmosphere!

50. Latitude Lines