Why does the moon change shape?
Talk about it together
Which moon shape do you like looking for in the sky?
What about...?
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Transcript
Have you seen the moon look round one night and like a tiny smile another night?
The Sun shines on the moon all the time. It lights up one half of the moon.
The moon moves around Earth, like it is taking a long trip around us. As it moves, we see a different part of its bright half.
Sometimes we see a thin bright curve, and sometimes a bright round moon. The moon stays round, but the sunlight we see changes.
So that's why the moon seems to change shape. It is really sunlight changing the part we can see!
For grown-ups: the science
The moon stays round, but as it moves around Earth, we see different sunlit parts of it.
The Moon is always a sphere, with half of it illuminated by the Sun. As the Moon orbits Earth, the Sun-Earth-Moon angle changes, producing the phases: crescent, quarter, gibbous, and full moon.