Primary science has been a major success story over the past 20 years in the UK. Children like science, and teachers, who may not have thought of themselves as "science-trained", have taken to the subject with gusto. Part of this enthusiasm is because of the practical nature of the subject. Science in UK schools makes good use of practical work to allow children to see science in action, to discover evidence and to investigate a wide range of "what if?" questions. In this article, the author explains why primary teachers and children really should do practical work. (Contains 3 figures.)