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Phase Positions Demonstrator
Phase is about the Moon's place in its orbit, not Earth's shadow. Shadow causes eclipses, not everyday phases.
First Quarter
Before you start
Place the Moon on its orbit and read the phase. This is the geometry behind the vocabulary lab.
Key idea
Full moon is opposite the Sun. New moon is between Earth and the Sun. No shadow of Earth is required.
What you see
- Sun, Earth, labelled orbit
- Moon disk matching the position
Try this
- Jump with the name buttons
- Stop at third quarter and check the disk
Common mistakes
- Drawing Earth’s shadow onto the Moon at first quarter
Glossary
- Opposition of Moon
- Full moon — Moon opposite the Sun.