Question

You will observe the Moon and its position in the evening sky every night for approximately 2 weeks as it goes from new moon to full moon. 1. Why does the amount of the moon that is lit up change from night to night? 2. Why must your observations be made at the same time every day for this project to work? 3. Why couldn't we continue this project in the same way for a full lunar cycle?

Answer 1

1. Because moon is also revolving around earth and one side of moon is always lit up but we can't see that bright side all the time instead we are able to see the moon in phases due to it's revolution around earth.

2. Because it is easier to measure the change in moon phase from some fixed reference point and since both earth and moon keeps rotating due to which phases of moon keeps changing hence it is necessary to fix a reference point

3. Because phase of moon is not constant through out its lunar cycle instead it reverses it's cycle after every full moon