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Science

Phases of the Moon

Overview

Students model the Moon's orbit around Earth using a torch and a ball, discovering why the Moon appears to change shape throughout the month.

Learning Objective
Students understand what causes the phases of the Moon and can predict the phase visible on a given date.

Resources needed

  • A torch or sunlight
  • A small ball or fruit to represent the Moon
  • A dark space if possible

Lesson stages

0 / 7 done
  1. 1 Ask: does the Moon change shape? (It looks like it does, but it does not — only the lit side we see changes).
  2. 2 Hold the ball at arm's length in a darkened space.
  3. 3 Shine the torch at the ball — half is lit, half is dark.
  4. 4 Slowly move the ball around the student — observe how the lit portion changes from their perspective.
  5. 5 Name the phases: new moon (all dark), crescent, quarter, gibbous, full moon.
  6. 6 Ask: why does the Moon take about 28 days to cycle through all phases?
  7. 7 Connect to tides: the Moon's gravity affects the oceans — tides follow the lunar cycle.

Tap a step to mark it as done.

Variations

  • Observe and draw the Moon each evening for a month — record the changing phase.
  • Discuss a lunar calendar — cultures that use months based on the Moon.
  • Connect to eclipses: when Earth blocks sunlight from the Moon (lunar eclipse).
More information

Teach: phase, orbit, reflect, crescent, gibbous, full moon, new moon, lunar. The physical model is essential — the phases are impossible to understand through description alone.

Focus on the full moon and new moon first — the extremes — before introducing the intermediate phases.

Can students explain why the Moon appears to change shape? Can they name and draw four phases of the Moon in the correct sequence?

Any ball or round fruit and a torch or bright light source work as a model.

Students almost universally think the Moon changes shape because Earth casts a shadow on it. Phases are caused by our changing viewing angle of the lit half — lunar eclipses are a different, rarer phenomenon.

Moon phases connect astronomy to cultural practices — many calendars, farming traditions, and religious festivals are tied to the lunar cycle.

Activity details
Primary Medium 25 minutes 5 minutes prep Whole Class, Small Group Indoor & Outdoor
Topics
Moon Earth And Space Patterns