# Describe how the phases of the Moon are caused by the Moon's orbit around the Earth.

> Cambridge International IGCSE Physics (0625) — 6.1 Earth and the Solar System · Describe · 4 marks

> The Moon is a natural satellite of the Earth with an orbital period of approximately one month. During this time, observers on Earth see the Moon's appearance change from a new Moon to a full Moon and back again.

## Mark scheme (4 marks)

1. The Moon is visible because it reflects light from the Sun
2. As the Moon orbits the Earth, the proportion of the illuminated surface visible from Earth changes
3. At new Moon, the illuminated half of the Moon faces away from Earth, so the Moon appears dark
4. At full Moon, the illuminated half of the Moon faces towards Earth, so the whole disc appears lit

## Key terms

- [orbit](https://www.gradenine.co.uk/glossary/orbit)

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-the-phases-of-the-55da9520) · Published by Druglandscape Ltd.