Moon Phases

This model shows the half of the Moon the Sun always lights, from the side, next to the view seen from Earth. Students drag the Day of cycle slider from 0 to 29.5 days or turn on Auto orbit, and optional markers name each phase. Readouts show the phase, percent illuminated, moon age and approximate moonrise time. It helps students see that phases come from our changing viewing angle and not from Earth's shadow, and it works for sequencing the eight phases and connecting waxing and waning to the cycle.

• Set Day of cycle to 0 and read the Phase and Illuminated readouts at new Moon.
• Move the slider to about day 7 and 15 and compare the two views of the Moon.
• Turn Phase markers on and name each phase before the label appears.
• Run Auto orbit and watch Moon age and Moonrise change through the month.
• Find a day when the Moon is waxing and another when it is waning.

1. 1Order the eight phases of the Moon through one cycle.
2. 2Explain that half of the Moon is always lit and phases depend on our viewing angle.
3. 3Distinguish waxing from waning phases.
4. 4State that the cycle takes about 29.5 days.

Questions teachers ask