Are children learning when they are "messing about" in sand or water? Is it science? In a workshop presented at the ASE Annual Meeting in Birmingham (January 2003), "Messy science: planning for learning in the foundation stage," delegates examined the nature of an early years curriculum through first-hand experience of a variety of familiar materials. Participants really did get messy, shared ideas and used a range of process skills as they considered the opportunities for children's learning. The focus of the workshop was to identify the potential for learning scientific processes and concepts in the range of materials provided. In this article, the author investigates the opportunities for learning in science through play. She believes that the most important point when planning for learning in the foundation stage is that practitioners recognise the distinctiveness of science. They may also have to convince others that when children are playing (messing about!) the potential for learning is huge.