The development of a science education that includes a focus upon the nature of science suggests the need for "pedagogic tools" that can be used to engage children with the procedural understandings that are central to the scientific approach to enquiry. This paper reports on a collaborative action research project that focused on the use of secondary data as just such a "tool" for stimulating engagement with procedural understandings among primary school children. It argues that the comparative analysis of secondary and investigative data "can" provide a basis for such engagement. However, such comparative analysis will only mirror the collaborative nature of the scientific enterprise where children have guided opportunities to discuss their understanding of the issues revealed by the comparisons. The research suggests that children work best with this data if the scientific approach to enquiry is contextualized through connection with the knowledge claims made in science. (Contains 1 figure and 2 tables.)