1. Moon Phases

2. The sun shines on ½ half of the Moon’s surface all the time
The sun shines on ½ half of the Moon’s surface all the time. (The moon does not produce its own light!) As the Moon orbits the Earth, we see different parts of the lighted area.

3. The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky. 

4. This is caused by the different angles from which we see the lighted part of the Moon's surface.  These are called "phases" of the Moon. 

5. Third (or Last) Quarter
The Moon passes through eight major shapes (phases) during a cycle that repeats itself every 29.5 days.  The phases always follow one another in the same order:
New Moon
Waxing Crescent
First Quarter
Waxing Gibbous
Full Moon
Waning Gibbous
Third (or Last) Quarter
Waning Crescent

6. Question: Can you name the month that is not long enough for a complete lunar cycle?
Answer……February (only 28 or 29 days)

7. Terminator The line between the light and dark part of the moon.
The terminator moves left as each day passes!

8. New Moon
The lighted side of the Moon faces away from the Earth.  This means that the Sun, Earth, and Moon are almost in a straight line, with the Moon in between the Sun and the Earth.  The Moon is not visible.

9. New Moon

10. ("Waxing" means increasing, or growing larger.)
Waxing Crescent Moon
This Moon can be seen after the New Moon, but before the First Quarter Moon.  The crescent will grow larger and larger every day as the terminator line moves left.
("Waxing" means increasing, or growing larger.)

11. Waxing Crescent Moon

12. First Quarter Moon ½ of ½ = ¼
The right half of the Moon appears lighted and the left side of the Moon appears dark. Although ½ of the Moon’s total surface has sunlight shining on it, we can only see ½ of that area. That is why it is called the first quarter and not the first half.
½ of ½ = ¼

13. First Quarter Moon

14. Waxing Gibbous Moon
This Moon can be seen after the First Quarter Moon, but before the Full Moon.  The amount of the Moon that we can see continues to grow larger and larger every day.

15. Waxing Gibbous Moon

16. Full Moon
The lighted side of the Moon faces the Earth.  This means that the Earth, Sun, and Moon are nearly in a straight line, with the Earth in the middle.  The Moon that we see is very bright from the sunlight reflecting off it.

17. Full Moon

18. "Waning" means decreasing, or becoming less.
Waning Gibbous Moon
This Moon can be seen after the Full Moon, but before the Last Quarter Moon.  The illuminated part of the Moon that we can see becomes less every day.
"Waning" means decreasing, or becoming less.

19. Waning Gibbous Moon

20. Third Quarter Moon
Third or Last Quarter.  The left side of the Moon appears lighted, and the right side of the Moon appears dark. This phase is also called the Last Quarter.

21. Third Quarter Moon

22. Waning Crescent Moon
This Moon can be seen after the Last Quarter Moon and before the New Moon.  The crescent will grow smaller and smaller every day, until the New Moon.

23. Waning Crescent Moon

24. Summary…. The Sun always shines on ½ of the Moon’s surface.
Phases are the result of seeing different amounts of the illuminated surface as the Moon revolves around the Earth.
The full cycle of phases takes 29.5 days and then starts over.
The terminator line separating light from dark always moves to the left.
Waxing – Becoming more and more visible “Bright on the Right”
Waning - Becoming less and less visible “Light on the Left”
The phase looks the same from every location on Earth.
On one day every cycle, the Moon is not visible. (New Moon)
The moon does not make its own light, it reflects the Sun’s light.

25. Waxing & Waning

27. Moon Movie
The movie is an animated GIF created by Antonio Cidadao from a sequence of still images taken during March and April 1998.
Copyright Antonio Cidadao.

28. Name each phase in the following slides….
Begin

29. Waning Gibbous Moon

30. First Quarter Moon

31. Waning Crescent Moon

32. Waxing Gibbous Moon

33. Waxing Crescent Moon

34. Full Moon

35. Third Quarter Moon

36. New Moon

37. Waxing Crescent Moon

38. Waning Gibbous Moon

39. Third Quarter Moon

40. Waning Crescent Moon

41. First Quarter Moon

42. Full Moon

43. Waxing Gibbous Moon