The phases of the moon change in a cycle from new moon to full moon and back again over approximately 29.5 days. The moon appears to change shape from a thin crescent to a half moon and then full circle as it orbits Earth, with the illuminated portion increasing and then decreasing over the cycle. During certain phases, a lunar eclipse can occur when the moon passes through Earth's shadow.

1. PHASES OF THE MOON

11. Oooh!
Aaah!

12. New Moon

14. Waxing Crescent

16. First Quarter

18. Waxing Gibbous

20. Full Moon

23. Waning Gibbous

25. Last Quarter

27. Waning crescent

29. Lunar eclipse
How Does the moon
change its phase?
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