Moon Phases Orrery
by ArcadeLabA hands-on orrery that finally makes Moon phases click. The Sun lights one side of everything; drag the Moon around its orbit and an inset shows exactly what the Moon looks like from Earth — new, crescent, quarter, gibbous, or full. Day and night sweep across Earth at the same time. Kids discover that phases aren't shadows of the Earth, just our changing view of the Moon's sunlit half.
Frequently asked
What causes the phases of the Moon?
The Sun always lights up one half of the Moon. As the Moon orbits Earth, we see different amounts of that lit half — sometimes all of it (full moon), sometimes none (new moon), and crescents and quarters in between.
Are moon phases caused by Earth's shadow?
No — that is a common mix-up. Earth's shadow only touches the Moon during a lunar eclipse. Ordinary phases happen because we are viewing the Moon's sunlit side from different angles as it orbits.
How long does it take the Moon to go through all its phases?
About 29.5 days. That full cycle from one new moon to the next is where the idea of a month comes from.