Where Does Light Come From?

Imagine you walk into a room and someone switches off every single light. It is completely dark. You cannot see anything at all. Now someone strikes a match — and suddenly a tiny flame pushes the darkness back. How did that tiny flame do that? Today you are going to find out. Light has to come from somewhere, and not every bright-looking thing actually makes its own light. Can you already think of two things that give off light?