Boxi Learn › Science › Stage 2 · Models and Patterns
Why does the Moon change shape?
SCI-6 Big and small, fast and slowX-3 Look from another sideX-1 Guess, then check
What many people think
The Moon's phases are Earth's shadow falling on the Moon.
The idea
Half of the Moon is always lit by the Sun; as the Moon goes round Earth in about a month, we see different amounts of that lit half.
Explain it
A friend says the crescent Moon is Earth's shadow. Use the first-quarter Moon (where are the Sun, Earth and Moon?) to change their mind.
Try at home
In a dark room with one lamp on one side, hold a ball at arm's length and turn slowly on the spot. Watch the lit part of the ball grow and shrink — your head is Earth. Bonus: draw the Moon each evening for two weeks.