1. Warm Up 1.Write 3-5 sentences about our Moon. What do you know about our Moon? 2.Write 3-5 questions that you would like to find out the answer to-relating to our Moon and/or other Moons surrounding other planets. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 1

2. The Moon

3. Lesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 3 Motivation  Learning about the Moon helps us understand Earth.  Can help us hypothesize about other moons orbiting other planets. Moonset on a clear desert morning

4. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 4 Overview 1.How big is the moon? 2.How does the Moon’s size and interior differ from the Earth’s? 3.What effect does this difference have? 4.What is the Moon’s surface like? 5.How does the Moon orbit the Earth? 6.What causes tides? 7.What causes eclipses?

5. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 5 Lesson overview  How big is the Moon?  How does the Moon’s interior differ from the Earth’s?  What effects does this difference have?  What does the Moon’s surface look like?

6. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 6 Introduction  Apollo program (1963-1972)  12 astronauts have walked the moon and observed its surface

7. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 7

8. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 8 1. How big is the Moon?  The Moon is 3,468 km in diameter  ¼ the Earth’s diameter (Earth = 12,800 km) 12,800 km 3468 km

9. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 9 2. How does the Moon’s interior differ from the Earth’s?  Moon’s interior is nearly inactive.  What explains this inactivity?  Small size - must have cooled off much faster than Earth

10. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 10 How does the Moon’s interior differ from the Earth’s? (cont’d)  Moon has less natural radioactive material to supply internal heat  Convection unable to occur  Therefore, no plate tectonics

11. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 11 How is the Moon’s interior similar to Earth’s interior?  Moon has crust and mantle made of silicates  Mantle: cold and rigid  Core: liquid but contains less iron and nickel than Earth

12. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 12 3. What are the effects of the Moon’s small size?  Apollo astronauts confirmed that the Moon does not have a magnetic field because:  Cold interior  Low levels of iron  No rotation in core

13. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 13 What are the effects of the Moon’s small size? (cont’d)  No atmosphere: interior too cold.  No magma to be pushed to surface for volcanic activity  Even if there were volcanoes, there is no gravity so the gases could not be held in an atmosphere  Lack of atmosphere = vacuum  Vacuum leads to hot during day and very cold at night

14. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 14 What does the Moon’s surface look like?  The Moon’s surface looks the same today as it did millions of years ago… Highlands Maria

15. What does the Moon’s surface look like?  2 major regions: Highlands and Maria  Highlands  bright, rugged areas pitted with craters  Maria  large, smooth, dark areas  Both regions are covered with regolith: a layer of shattered rock chunks and powder that is hundreds of feet thick. This comes from repeated meteor impacts. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 15 Highlands Maria

16. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 16 What does the Moon’s surface look like? (cont’d)  The Moon has other surface features:  Craters: circular features with a raised rim caused by meteor impacts  Rays: long, light streaks of pulverized rock radiating away from many craters  Rilles: lunar canyons carved either by cracking of the crust Craters Rays Rille

17. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 17 What does the Moon’s surface look like? (cont’d)  Desolate surface  Unchanged for a long time  Reason: no atmosphere = no erosion no plate tectonics = no earthquakes/volcanoes

18. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 18 Lesson review  How big is the Moon?  ¼ Earth’s diameter  How is the Moon’s interior different from the Earth’s?  Nearly inactive  How did the Moon’s size affect its internal heat?  Faster cooling  Less internal heat ?

19. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 19 Lesson review (cont’d)  Why doesn’t the Moon have a magnetic field?  Size, nature, and motion of core  Why doesn’t the Moon have an atmosphere?  No volcanoes, no gases  Weak gravity ?

20. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 20 Lesson review (cont’d)  What does the Moon’s surface look like?  Desolate  Two major regions:  Highlands  Maria ?

21. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 21 Lesson review (cont’d)  Other surface features:  Craters  Rays  Rilles ?

22. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 22 Activity—Questions for review  How big is the Moon?  How is the Moon’s interior different from the Earth’s interior?  Why doesn’t the Moon experience plate tectonics?  What are the lunar surface’s two main regions?  What are craters and rays?

23. The MoonLesson 11: Chap 3, Secs 3.1-3.2 Description and Structure of the Moon 23 Summary  How big is the Moon?  How does the Moon’s interior differ from the Earth’s?  What effects does this difference have?  What does the Moon’s surface look like?

24. The Moon, Part 2 Arny, 3 rd Edition, Chapter 3

25. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 25 Chapter overview  How does the Moon’s size and interior differ from the Earth’s?  What effect does this difference have?  What is the Moon’s surface like?  How does the Moon orbit the Earth?  What causes tides?  What causes eclipses?

26. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 26 Motivation  The Moon’s motion  We only see half of the moon  Causes ocean tides Moonset on a clear desert morning

27. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 27 Lesson overview  Where is the Moon?  How does the Moon move around the Earth?  How does the Moon cause tides?

28. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 28 Introduction  Back side of Moon first photographed in 1960s.  Moon forms Earth’s coastlines

29. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 29

30. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 30 Where is the Moon?  The Moon—Earth’s nearest neighbor  About 380,000 km (237,500 mi) away  Moon orbits Earth about once every 27.3 days Earth Moon Baseball Marble 5.6 m or 18 ft Earth Moon

31. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 31 How does the Moon move around the Earth?  Rotates once on its axis every 27.3 days (a lunar “day”)  Keeps same face toward Earth The Moon rotates once each time it orbits the Earth. Notice that at (A) the lunar peak is to the right; at (B) it’s to the left.

32. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 32 How does the Moon cause tides on Earth?  Tides—regular change in height of ocean’s surface  Cause—Moon’s gravity Tides are caused by the Moon's gravity, which creates tidal bulges. QuickTime Movie: Tides

33. The MoonLesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides33 How does the Moon cause tides on Earth? Here, Moon’s gravity pulls the Earth “out from under” the water, creating a tidal bulge on the far side. Here, Moon’s gravity acts more strongly on the water than on the Earth. This pulls water away from the Earth, creating a tidal bulge.

34. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 34 How does the Moon cause tides on Earth?  Earth’s rotation leads to two high and low tides per day.  Moon is why we have tides, Earth is why we have 2 high/2 low per day Person at high tide Person at low tide

35. Moon and Earth rotation skit  Volunteers:  One Sun  One Moon  One Earth (might get dizzy!) The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 35

36. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 36 How does the Sun affect tides?  The Sun also creates tides but has less effect than the Moon. Spring tides Neap tides

37. Spring tides  When Sun and Moon are in line, the effects of their gravity add up to make larger than normal tides. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 37

39. Neap tides  When the Sun and Moon are at right angles to one another, the effects of their gravity partly cancel each other to make smaller-than-normal tides The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 39

40. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 40 Is the Moon slowing us down?  Yes: tidal braking- tides create forces that slow the Earth’s rotation and move the Moon farther away  Because of tidal braking:  Moon keeps one face locked on Earth  Moon moves about 3 cm (~1 inch) farther away each year!  Earth’s rotation slows down-days are getting about 0.002 sec longer each century

41. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 41 Lesson review  How far away is the Moon?  About 380,000 km (237,500 mi) away  How does the Moon move around the Earth?  Orbits the Earth and rotates on its axis in same number of days  So always keeps the same face toward the Earth

42. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 42 Lesson review (cont’d)  How does the Moon cause tides on Earth?  Moon’s gravity creates two tidal bulges.  One bulge on side of Earth nearer the Moon; other bulge on far side  Does the Sun cause tides on Earth?  Yes, but with weaker effect than the Moon’s

43. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 43 Activity—Questions for review  How far away is the Moon?  How long does it take for the Moon to complete one orbit around the Earth?  Do we ever see the “dark side” of the Moon? Why or why not?  Why is there a high tide on the side of Earth nearest to the Moon? On the side of Earth farthest from the Moon?  What happens when the Moon and Sun both pull in the same direction?  What happens when the Moon and Sun pull at right angles to each other?

44. The Moon Lesson 12: Chap 3, Sec 3.3 and 3.6 The Moon's Motions and Influence on Tides 44 Summary  Where is the Moon?  How does the Moon move around the Earth?  How does the Moon cause tides?

45. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 45 The Moon – Part 3  How does the Moon’s size and interior differ from the Earth’s?  What effect does this difference have?  What is the Moon’s surface like?  How does the Moon orbit the Earth?  What causes tides?  What causes eclipses?

46. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 46 Motivation  Eclipses help us understand the complex movements of the Sun, Earth, and Moon. Moonset on a clear desert morning

47. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 47 Lesson overview  What’s an “eclipse”?  How often do eclipses happen?  What do eclipses look like?

48. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 48 What’s an eclipse?  An eclipse—when one body casts its shadow on another  Two types on Earth:  Lunar eclipse  Solar eclipse

49. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 49 What’s an eclipse? (cont’d)

50. What’s an eclipse?  The Moon's orbit around the Earth tilts slightly compared to Earth’s orbit around the Sun. Because of this tilt, the Moon usually is either above or below Earth’s orbit. Eclipse seasons occur when the Moon's orbit puts the Sun, Moon, and Earth in a direct line. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 50

51. Types of eclipses  Solar eclipse—Moon directly between the Sun and Earth. Earth’s shadow falls on Moon. New Moon  Lunar eclipse—Earth directly between the Sun and the Moon. Moon’s shadow falls on Earth. Full Moon The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 51

52.  Lunar Eclipse: http://www.youtube.com/watch?v=IKQk M474UE0&feature=related http://www.youtube.com/watch?v=IKQk M474UE0&feature=related  Solar Eclipse: http://www.youtube.com/watch?v=DVqe w5gJU2o&feature=related http://www.youtube.com/watch?v=DVqe w5gJU2o&feature=related  Both: http://www.youtube.com/watch?v=P2S5 zcJ6_8s&feature=related http://www.youtube.com/watch?v=P2S5 zcJ6_8s&feature=related The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 52

53. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 53 How often do eclipses happen?  The Moon’s orbit tilts nearly in the same direction throughout the year  This orbit passes between the Earth and Sun TWICE A YEAR. This is when eclipses occur. QuickTime movie: Eclipses

54. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 54 What do eclipses look like?  Lunar eclipse  Total lunar eclipse—Earth’s shadow takes about one hour to cover the Moon.  Totally eclipsed Moon has deep red color.  Reason: Earth’s atmosphere scatters out most of the blue in sunlight and bends the remaining reddish light at the Moon

55. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 55 What do eclipses look like? (cont’d) (A) (A)Photograph of a total lunar eclipse. (Photo courtesy Dennis di Cicco.) (B) (B)Shows reddish color that occurs because of the effects of Earth’s atmosphere on sunlight. Light from the Sun

56. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 56 What do eclipses look like? (cont’d)  Solar eclipse brings a short night in the middle of the day. (~7 min)  Stars come out  A solar corona also appears at total eclipse.-Sun’s outer atmosphere (A) Photograph of a total solar eclipse. The bright halo of light is the Sun's corona—its outer atmosphere. (Photo courtesy Dennis di Cicco.) (B) The landscape is eerily lit during a total solar eclipse. The sky’s dark color is the Moon's shadow. (Courtesy Richard Wainscoat.)

57. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 57 Lesson review  What’s an “eclipse”?  An eclipse occurs when one astronomical body casts its shadow on another.  Two types on Earth:  Lunar eclipse  Solar eclipse  How often do eclipses happen? Why not more often?

58. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 58 Lesson review  What do eclipses look like?  Total lunar eclipse—Moon usually looks deep red  Solar eclipse brings a short night in the middle of the day:  Stars come out.  Animals go to bed.

59. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 59 Activity—Questions for review  What’s the difference between a lunar eclipse and a solar eclipse?

60. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 60 Activity—Test yourself  A ______ happens when Earth’s shadow falls on the Moon.  A solar eclipse happens when the _____’s shadow falls on the ______.  A ______ brings a short night in the middle of the day.

61. The MoonLesson 13: Chap 3, Sec 3.5 Eclipses 61 Summary  What’s an “eclipse”?  How often do eclipses happen?  What do eclipses look like?