Phases of the Moon

Students model the phases of the Moon using a lamp, a styrofoam ball, and movement to simulate Earth, the Sun, and the Moon. This activity helps explain why the Moon’s appearance changes over the month and allows students to observe the lunar cycle themselves.

1. Place a lamp with a bright bulb in the center of a darkened room to represent the Sun.
2. Give each student a styrofoam ball on the end of a pencil to represent the Moon, with the student acting as Earth.
3. Have students stand facing the lamp and slowly rotate counterclockwise, holding their “Moon” at arm’s length.
4. At different positions, observe how the lit portion of the sphere changes, representing Moon phases:
5. Provide Moon Observation Sheets for students to track actual lunar phases over 30 days.

Sun, Moon and Earth Model - Armagh Observatory & Planetarium:

Classroom Demonstrations: Phases of the Moon - Institute of Physics:

📄 Moon Phases - NASA STEMonstrations: https://www.nasa.gov/wp-content/uploads/2020/09/stemonstrations-moon-phases-508.pdf

• Use a globe for Earth and walk the Moon model around it to emphasize orbital motion.
• Incorporate an outdoor night-sky observation session to match real Moon phases with the model.

• Ensure the room is clear of obstacles so students can rotate safely.
• Use a stable lamp that will not tip over during the activity.
• Avoid staring directly into the bright bulb.

• Why do we see different phases of the Moon from Earth? (Because the Moon orbits Earth and we see different portions of its sunlit half.)
• Why does the Moon’s cycle take about 30 days? (That is how long it takes the Moon to orbit Earth once.)
• Why is the Moon not always visible at night? (Its position relative to Earth and the Sun may place it in the daytime sky, or it may be in the new Moon phase.)
• How do solar and lunar eclipses relate to the Moon’s phases? (A solar eclipse occurs near a new Moon when the Moon blocks the Sun; a lunar eclipse occurs near a full Moon when Earth blocks sunlight from reaching the Moon.)