Why the Moon Changes Shape

Use the orbit diagram to work out what an observer on Earth sees.

8 questions, free, marked as you go with a worked explanation on every one.

What this covers

The questions

  1. In the diagram, the sunlight arrives from one side only. What does that mean for the Moon?
  2. Using the diagram, why do we see phases at all?
  3. In the diagram, the Moon is on the far side of Earth from the Sun. What phase does an observer on Earth see?
  4. In the diagram, the Moon sits between Earth and the Sun. What is seen from Earth?
  5. The Moon takes about 29.5 days to go once round the positions in the diagram. About how many days pass between a new moon and the full moon that follows it?
  6. Which statements does the orbit diagram support? Select all that apply.
  7. Light takes about 1.3 seconds to reach us from the Moon. Roughly how many seconds does a round trip signal take?
  8. Using the diagram, why do we always see the same face of the Moon from Earth?

Answer these free