Question

Why does the shape of the moon change..

Answer 1

The moon appears to change shape because we see different amounts of the lit part as the moon orbits earth

Answer 2

The Moon appears to change shape because we see different amounts of the lit part as the Moon orbits Earth. When the Moon is between Earth and the Sun, the lit side is hidden from us. As it moves around Earth, more and more of the lit side comes into view.