sketchplanations:

Phases of the moon.

It’s good to know your waxing (growing) from your waning (shrinking), and that a gibbous is the shape of the moon when you take a crescent of shadow from a circle of light, and that the hardest moon to see is a new one.

Like the moon? Apparently so do I: See the moon illusion, super moon, one side of the moon or just sketchplanations > astronomy.