The Moon changes shape in our view, not in space.

Follow the light

NASA explains that moonlight is reflected sunlight. As the Moon moves around Earth, we see changing portions of its sunlit half. The familiar phase cycle repeats roughly every 29.5 days; the Moon is not physically growing or shrinking.

Reference: NASA — Moon phases ↗.

Put the names in order

New Moon, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, last quarter and waning crescent form the usual eight-name sequence. “Waxing” describes an increasing illuminated portion in our view; “waning” describes a decreasing one.

Use the studio as a model

The Moon studio changes explanatory text when you select a phase. It is not a current-phase display, a moonrise calculator or a visibility forecast. The simple disc is a schematic illustration for learning, not a photograph or a precise projection.

Separate the label from the observation

Select a phase, read its explanation, and predict whether more or less of the disc should appear illuminated at the next named phase. Then move forward one step and check your reasoning. Do not infer a local viewing time from the position of a tab.