Moon Phases 101 Last updated Save as PDF Page ID185385 To Do To Answer Read about the phases of the moon Why can people on earth only see one side of the moon at all times? How is the last question important in our understanding of the phases of the moon? How much of the moon is lit by the sun at all times? Watch the animation. Work through the interactive. Click on Monthly Cycles. Draw each phases of the moon and label with the phase name. Define waxing and waning.