The Moon does not make its own light. It reflects sunlight. As it travels around Earth, we see different amounts of its bright half. The Moon itself keeps the same shape.
Space · Discover & try
Why does the Moon appear to change shape?
Reading level 1 of 5 · EarlyChange
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Phase
The apparent shape of the sunlit Moon seen from Earth.
Waxing
The visible sunlit portion is growing.
Waning
The visible sunlit portion is shrinking.
Watch · Try · Explain
See how it works
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Eight checkpoints in a continuous cycle; north-pole orbital view and Northern Hemisphere Earth-view orientation. Sizes and distances are not to scale.
What to look for
- Compare the orbital view with the view from Earth.
- Find both half-lit quarter phases.
- Follow waxing phases through to full Moon.
Explain what you noticed
Why does the Moon appear to change shape?
Keep this idea: Moon phases come from our changing view of the Moon’s sunlit half.
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Source material checked 2026-10-28. Explanations and activities by Nepedia. Agency source links do not imply endorsement.
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