The Sun's light only ever lights up half of the Moon.
As the Moon orbits Earth, we see different amounts of that lit half — that makes the phases.
Waxing means the bright part is growing. Waning means it's shrinking.
When the Sun, Earth and Moon line up you get an eclipse! 🌑
Drag the Moon or use the sliders — one moves the Moon, one sets the orbit speed. The circle shows what you'd see from Earth!