Phases of the Moon — Interactive Diagram
See why the Moon seems to change shape through the month — from new moon to full moon and back.
TL;DR: See why the Moon seems to change shape through the month — from new moon to full moon and back.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Phases of the Moon: See why the Moon seems to change shape through the month — from new moon to full moon and back.
Why it matters: Moon phases depend on how much of the sunlit side faces Earth — a favourite question and the basis of the lunar calendar and tides.
Phases of the Moon — Step by Step
- NEW MOON: the Moon is between the Sun and Earth, so its lit side faces away from us — we see almost nothing.
- FIRST QUARTER: a week later we see exactly half of the lit side — a half-moon shape.
- FULL MOON: Earth is between the Sun and Moon, so we see the entire sunlit face — a bright full circle.
- LAST QUARTER: the lit half shrinks back to a half-moon on the other side, then to new moon — and the cycle (~29.5 days) repeats.
Quick Notes — the Exam Crux
- The Moon does not produce its own light; it reflects sunlight.
- Phases depend on how much of the Moon's sunlit half faces Earth as it orbits.
- Order: new Moon (not visible) → waxing crescent → first quarter → waxing gibbous → full Moon → waning gibbous → last quarter → waning crescent.
- Waxing = the lit part is growing; waning = the lit part is shrinking.
- One complete cycle of phases takes about 29.5 days.
- The Moon takes the same time to rotate once as to orbit Earth, so we always see the same face.
Remember It (Memory Trick)
The Moon makes no light — we only see its sunlit half. Waxing = growing, Waning = shrinking. One full cycle takes about 29.5 days.
Real-Life Example
On Karva Chauth or Eid, people watch for the thin crescent moon — that sliver is just the small sunlit part of the Moon we can see from Earth that night.
Test Yourself
Does the Moon produce its own light?
No — it reflects light from the Sun.
What decides the Moon phase we see?
How much of the Moon's sunlit half is facing Earth at that point in its orbit.
What is the difference between waxing and waning?
Waxing means the lit portion is growing toward full; waning means it is shrinking toward new.
📖 Read the full explanation of Phases of the Moon →
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