Models and analogies can help understanding, help explain the world and make a process or structure that one cannot easily see more explicit. Models and analogies can help children to visualise abstract processes and make ideas concrete. Children enjoy working with them because they are motivating and often require creative thought. Models and analogies can be used in a variety of ways: (1) to introduce a lesson; (2) to allow observation; (3) to challenge children's thinking; and (4) to allow children to make structures and processes more explicit by making their own versions. The main reason, to the author's mind however, is to support discussion. In this article, the author explores some of the models used in primary science to help explain science and whether they are "good enough." (Contains 7 figures and 2 online resources.)