Noether's theorem

Noether's theorem is a very important math idea that explains how if something is not changing in some way, there will be other ways that are related and stay the same. Imagine a box that contains the same amount of rubber balls. Even if you move the rubber balls around inside the box, the number of balls will stay the same. That's like Noether's theorem - if something is not changing, then things related to it will also stay the same.