Divergence theorem

The divergence theorem is a way of understanding how things flow and spread out in space. It's like a map that shows where things are going, with arrows that point in different directions. The arrows are called "vectors," and if you sum all the vectors together in a certain area, you can figure out if things are flowing out of the area (diverging) or if things are flowing into the area (converging). The divergence theorem helps us figure out how much stuff is flowing out of an area (like water from a fountain). It works by taking the sum of the vectors in a given area (like a ball) and then multiplying it by the area (the size of the ball). If the sum is positive, then things are diverging; if the sum is negative, then things are converging.