Moon Phases and Eclipses
- Earth & Space
- Ages 11–14 · Grades 6–8
What you’ll find out
- The Sun always lights half the Moon; phases come from seeing that half from changing angles.
- The cycle from new moon to new moon takes about 29.5 days.
- Solar and lunar eclipses happen when the Sun, Moon and Earth line up exactly.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
Why the Moon has phases
The Moon produces no light of its own; sunlight always illuminates the half of it that faces the Sun. As the Moon orbits Earth, which takes about a month, we see different amounts of that sunlit half. When the Moon lies between Earth and the Sun, its lit side faces away from us and we see almost nothing: a new moon. When Earth is between the Sun and Moon, we see the whole lit face: a full moon. In between come crescents, quarter moons and gibbous moons.
Eclipses
Occasionally the Sun, Moon and Earth line up exactly, causing an eclipse. In a solar eclipse, the Moon passes directly between the Sun and Earth, blocking the Sun’s light, and its shadow sweeps across part of Earth, turning day briefly into twilight. In a lunar eclipse, Earth passes between the Sun and the Moon, and Earth’s shadow falls on the full moon, often turning it a coppery red. You must never look directly at the Sun, even during an eclipse.
Curriculum links: NGSS MS-ESS1-1 · England KS3: Space physics · Cambridge Lower Secondary Stages 7–9: Earth and space · NCERT Science, Classes 6–8