Phases of the Moon
Explain the phases of the Moon as the changing angle of sunlight on the lunar surface as seen from Earth, and describe how solar and lunar eclipses occur
Lesson
Set out your lesson
“The Sun lights half the Moon. As the Moon orbits Earth, we see different amounts of that lit half. Ordinary phases are not made by Earth’s shadow. A full phase cycle takes about 29.5 days, not exactly 28 days. Eclipses require a special alignment because the Moon’s orbit is tilted. Safety: Never view the Sun or an eclipse as part of this task. No bright lamp needed. Stop: Stop at paper geometry; no sky observation or eclipse viewing is required.”
Bring to the table
- Paper
- Pencil
- Eight paper Moon disks
Extra for the adult
Worked example. At full Moon, Earth lies between the Sun direction and Moon direction, so we see the Moon’s sunlit face. Usually the Moon passes above or below Earth’s shadow. Only a close enough alignment gives a lunar eclipse.
Optional challenge. Explain why first quarter looks half lit rather than one-quarter lit.
What to notice. Keep the diagrams. Note adult-supplied phase order or eclipse alignments.
Share and support
Family records and proof options
Keep a record of your learning
Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.
Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
NASA Space Place · Practice link — not the full lesson
Moon
Before you open · source notes
Moon supports Phases of the Moon. An adult previews and guides; this is a learning page, not a scored quiz.
Free educational page, no sign-in required for the tested path.
Before you openAsk the learner one fact they learned and one question they still have.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public NASA Space Place page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
NASA Space Place. “Moon.” External page; Gakuva does not copy, host, embed, or redistribute materials.
Unknown — link only
Check understanding
- Explains that the phases of the Moon arise from the changing geometry of Sun, Earth, and Moon, not Earth's shadow
- Describes the sequence of Moon phases over approximately 28 days
- Distinguishes between a solar eclipse (Moon between Sun and Earth) and a lunar eclipse (Earth between Sun and Moon)
“If your child noticed the Moon looking like a thin crescent one night and a full circle two weeks later, could they explain what has changed and why — and describe what happens during a lunar eclipse?”
Curriculum record
- Type
- Conceptual
- Subject
- Science
- Domain
- Space Systems & Earth's History
- Age range
- Ages 11–12
Standards