Introduction - Concepts

Last updated at June 17, 2026 by

💬 Think about it

At the Kite Festival, Meera looked up and saw the Moon shining in broad daylight — and it wasn't even a full circle. She knew the Moon is round and only reflects sunlight. So why isn't the whole Moon visible every night? Let's solve Meera's puzzle.

Why doesn't the whole Moon look the same every night?
  • The Moon is spherical and shines by reflecting sunlight.
  • Its shape in the sky seems to change from day to day.
  • This is not caused by a lunar eclipse, which is rare and brief.
  • So something else causes the Moon's changing shape.
Example: Some nights the Moon is a full circle, other nights only a thin sliver is visible.
Important Points
  • The Moon shines by reflecting sunlight, not its own light.
  • Its visible shape seems to change from day to day.
  • This change is not due to an eclipse.
Important Definitions
  • Reflected light (of the Moon) — the sunlight the Moon bounces back, which is why we can see it.
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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant with 16+ years of practical experience and 20+ years of teaching experience. At Teachoo, he simplifies Accounts, Tax and GST with step-by-step examples so students can apply concepts confidently in exams and real life.

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