What is the reason for the changes in the phases of the moon during the lunar cycle?

Question

What is the reason for the changes in the phases of the moon during the lunar cycle?

Answer 1

For God’s sake let’s not have anyone coming on here and saying it is the Earth’s shadow.

Do you really not know?  Are you not aware that the moon is a ball, a sphere, and that the sun can only shine on one half at a time (like night and day on Earth).  

The phases then are simply how much of the sunlit part of the moon we can see, due to the changing positions of the moon relative to the sun.

Jeez, what do they teach you at school.  This is so basic…..

Answer 2

The moon rotates around the earth and the earth rotates around the sun.  It is known that the sun and moon oppose each other basically so when the sun is shining on the other side of the earth, the moon is visible to us.  The shadow occurs because the sun, earth, and moon are not in a linear correlation so whatever light from the sun the earth is blocking, casts a shadow on the moon.  :)

Answer 3

Here's a pretty good illustration of how the phases of the moon work.

A picture is worth a thousand words they say! :)

http://www.utahskies.org/image_library/s...

Answer 4

The moon orbits the Earth once in 29.5 days (the lunar cycle) and the phases of the moon are simply the amount of the sunlit side of the moon visible to the Earth at any given point in the moon's orbit.

Answer 5

The relative position of the sun and moon with respect to the earth cause the different phases.  This animation http://www.harcourtschool.com/activity/m... depicts it really well. I recommend pausing the animation at each phase and really looking to understand why the people on the Earth would see that phase at that time.