Why can we see the entire side of the Moon during a full Moon?

The simple answer is that we only see one side of the moon because the moon rotates around the Earth at the exact same angular speed (in fact it’s not exactly true – we’ll talk about it later too) as it rotates around its own axis, so that the same side of the moon is constantly facing the surface of the Earth.

Explanation:

When a full moon occurs it is because the earth is "between" the sun and moon. Between the new and full moon, the amount of moon we see grows (waxes). As it passes the full moon stage, the amount of illumination decreases (wanes).

I hope this helped.

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