Why Does the Moon Change Shape?

[woosh] Last week the moon was a banana smile, This week it's half — a curvy tile, A few more nights and it fattens round, Then over weeks it shrinks without a sound.

A whole month of slow shape-shifting, Why does the moon keep drifting? Round, then half, then a thin escape — Hop on board — let's investigate!

Half the moon is ALWAYS bright! Half the moon is ALWAYS night! The sun shines on one side flat — The moon just spins and turns like that!

The moon goes loop-de-loop round Earth A whole big circle — that's its worth And as it goes, we tilt our head And see new slices of bright instead

[click] Grab a flashlight, grab an orange Hold it up and slowly arrange — Light hits one side, dark on the back Spin the orange — watch the slice change track!

Half the moon is ALWAYS bright! Half the moon is ALWAYS night! We see a sliver, then a D, Then a fat O hanging free!

Crescent, gibbous, half, and full The names sound funny, but they're cool Same moon up there — no painted face, Just shadow shifting place to place

How do we know? How do we know? A long time back — Greek guy named Aristarchus — Measured the moon with sticks and shade, Watched the shadow line each phase parade!

He saw the curve, he saw the edge, He saw the sun's light meet the ledge. The dark part wasn't gone or hid — Just shadowed by what the sunlight did!

Half the moon is ALWAYS bright! Half the moon is ALWAYS night! We see a sliver, then a D, Then a fat O hanging free!

Tonight go peek before you sleep Wave at the slice the sun lets keep The other half is sitting there too — Hiding in shadow, watching you