1. PHASES OF THE MOON

2. We see the moon because the Sun shines on it
We see the moon because the Sun shines on it. The sunlight bounces off or reflects off the moon and onto the Earth. We see the reflected sunlight.

3. Regular changes of how the moon looks from the Earth are called the phases. Sometimes the moon looks completely dark and seems to disappear. This is called a new moon. Sometimes the moon looks round. This is called a full moon.

4. Phases of the Moon
After the new moon, the moon appears to change. More and more of the moon starts to show. This is a crescent moon. When the moon is growing larger, we call this a waxing moon.

5. A complete orbit of the moon around the Earth produces the moon’s phases that we see. This complete cycle of the moon’s phases takes about 28 days.

6. The Moon Facts about the Moon…
We see the moon changes its appearances and position in the sky in a monthly cycle.
Unlike the stars, Moon can also be seen during the day.
We also see that the Moon is always involved in eclipses.
Its position relates to the rise and fall of the tides
Understanding the motion of the Moon with respect to the Sun and the Earth will explain these phenomena.
The moon revolves around the earth with a period of about 29 ½ days ~ one month!

7. Motions of the Sun-Moon-Earth System
Earth orbits the Sun every 365 ¼ days
Moon orbits Earth every 28 days

8. The Face and Phases of the Moon
The phase (how much and which side of the Moon is illuminated) of the Moon changes with about one month period…
The face (the features on the surface of the Moon) does not change at all…

9. The Phase of the Moon
The phase of the Moon depends on the relative position between the Sun, the Earth, and the Moon…

10. Why do we always see the same side of the Moon?
The rotation period of the Moon is similar to the revolution of the Moon around the Earth.
Is this a coincidence?
No!  Objects very closely linked by gravity will eventually
“lock” into a certain type of position.
The same side of the Moon always faces the Earth.

11. Phases of the Moon

12. New Moon

13. Waxing Crescent

14. First Quarter

15. Waxing Gibbous

16. Full Moon

17. Waning Gibbous

18. Last Quarter

19. Waning crescent

29. Resources
Chapter 9:
Eclipse Interactive
Interactive
Lunar Phases Interactive
Phases Interactive
(Moon phases)
(animated Moon phases)
(Moon phases)

30. Review What is a phase? The phases of the Moon occur when …?
Does the same side of the Moon always face the Earth?
About how long does it take the Moon to orbit around the Earth?
About how long does it take for the Moon to make one rotation on its axis?
What is the difference between a full moon and new moon?

31. More Resources Moon Phases: