How do caches work?

I think it is fair to say that most people have an idea of what caching does at a variety of levels. To someone not in tech, "clearing your cache" (also those yummy cookies!) is a way to get your browser to update. So it is understood that some data is stored pretty close to you. To someone in tech, you may understand that caching data is a way to keep it accessible so that you don't have to go…