Continuity equation

The continuity equation is like a rule that tells us how things flow and change over time. It’s like a math equation that measures how much of something is flowing in and out of a place. For example, if you have a cup of water, the continuity equation can help you figure out how much water is in the cup and how that changes over time. For example, if you pour water into the cup, the continuity equation can tell you how much water is in the cup after adding the water. Or if you take water out of the cup, the continuity equation can show how much water is left in the cup. So in a way, it’s like a rule that tells us how much of something is going in and out of something else and how it all changes over time.