1. नमस्कार

3. Unit 21, Earth and universe 1.Explain the phases of moon with reasons. 2.Explain the terms: Crescent moon, New moon, Full moon.

4. 21.4 What is called Phases of moon? When we observe the sky daily for some days, we find that the moon changes its shape every day. It is called phases of the moon. Why does Phases of the moon occur?  because of following reasons:  The moon is the non-luminous body and reflects the sunlight.  The moon is revolving around the earth in its elliptical orbit.

5. Moon phases demo

6. Some interesting facts about the moon: The moon rises about 50 minutes late daily. The time of sunrise and moonrise is same in the new moon. On the full moon, the moon rises, at the time of the sunset. Moon rises at the mid-day on the first quarter. The moon rises at the midnight in the last quarter. The moon rises about 50 minutes after the sunrise on the waxing crescent. The moon rises about 50 minutes before the sunset on the waxing gibbous.

7.  After 24 hours, when the moon forms an angle 12 0 to the plane of its orbit, a little bright part of the moon faces towards the earth and a minimum part of the moon is seen bright. It is called waxing crescent (m2).  When moon forms an angle of 180 0 from the plane, the moon is seen completely round, which is called full moon.  When the moon forms an angle of 0 0 from the plane of earth’s orbit, the whole dark part of the moon faces towards the earth and hence any part of the moon is not seen i.e. is a new moon(m1). Terms:

8. With Love….