ABSTRACT
This article considers the emphasis on scientific evidence in the practical science curriculum in England and Wales, paying particular attention to some recent research findings concerning children's understanding in this area. The findings suggest that children's ability to conduct investigations in science appears to decline in the early years of secondary school. The authors discuss possible explanations for this decline which, it is suggested, contributes to a general failure among school children to make progress to higher levels of investigative work and in the acquisition of a real understanding of the nature of science itself.