The original project, the foundation for all subsequent work, was set up in 1981 by Michael Shayer, with Philip Adey and Carolyn Yates, and became known as CASE @ KS3 (Adey and Shayer, 1994). CASE stands for Cognitive Acceleration through Science Education. The original CASE project drew on Piaget's work on the stage theory of cognitive development (Inhelder and Piaget, 1958) and his related ideas on cognitive conflict and metacognition, and on Vygotsky's work on social construction and metacognition (Vygotsky, 1978). The outcome of the original CASE @ KS3 project is a set of 30 activities known as "Thinking science". These replace some science lessons and are accompanied by an ongoing supporting professional development programme for teachers. CASE @ KS2 (Cognitive Acceleration through Science Education at key stage 2) was established in 2001 at King's College London with funding from the AstraZeneca Teaching Trust. The idea was to explore the potential of setting up a similar intervention programme in year 3 through the science curriculum. In this article, the author outlines how the CASE approach is taking off in key stage 2. (Contains 1 table, 3 resources and 3 online resources.)