In the popular press, diagrams showing the evolution of the universe begin with a great jump in size labeled "inflation." Can we explain the basic ideas behind inflation to our students who have taken our introductory physics course? Probably not. In our standard introductory physics courses, even those with special relativity, something is missing. We do not talk about "how space behaves," and that is a key component in modern astronomy. This is the first of four papers dealing with the behavior of space. They focus on basic cosmology and a discussion of inflation, building on the ideas and experiments covered in introductory physics.