What are phases of moon?

Explanation

The various shapes of the bright part of the moon as seen during a month are called phases of the moon.
The day on which the whole disc of the moon is visible is known as the full moon day. Thereafter every night the size of the bright part of the moon appears to become thinner and thinner. On the fifteenth day the moon is not visible. This day is known as the .new moon day.. The next day only a small portion of the moon appears in the sky. This is known as the crescent moon. Then again the moon grows larger every day. Once again on fifteenth day we get a full view of the moon.
The moon does not produce its own light. We see the moon because the sunlight falling on it gets reflected towards us. We therefore, see only that part of the moon from which the light of the Sun is reflected towards us. This causes phases of moon to occur.