Children's conceptions of air pressure: exploring the nature of conceptual change

Children's responses to a series of air pressure activities were tracked in detail during group discussion and interview, and again in interview six months later. Results for different age cohorts have yielded insights into age‐related knowledge components framing children's conceptions of air pressure phenomena. Case studies of individuals have been constructed to explore the way conceptions change over time, and the difficulties presented by the concept of atmospheric pressure. These are used to evaluate different structural theories of conceptual change. The findings point to the complexity of children's conceptions, the stability and extension over time of productive conceptions, and the critical role of contextual features of phenomena in the conceptual change process. Although structural aspects of changes in concepts related to air pressure are identified, the difficulty of accessing the atmospheric pressure conception is argued to have more to do with presupposition based in perceptual features of air, and with difficulties associated with the application to particular phenomena.     

Dimensions of evidence,the public understanding of science and science education

This paper explores the nature and type of evidence employed by participants in an issue of public concern. By examining documents and interviewing members of the public involved in the debate, the way in which evidence was used in the arguments for and against the issue was determined. Three dimensions of evidence emerged from the data: formal scientific evidence based on the data; informal evidence (e.g. common sense, personal experience) and wider issues which impinge on the evidence (e.g. environmental or legal concerns). In this particular controversy, it was the questioning of the formal evidence by local scientists which became the 'magic bullet' but pertinent questioning by local nonscientists also framed the debate. The authors suggest that school science curricula should include practice in questioning and manipulating different sorts of real data in a variety of ways so that pupils are equipped and empowered to tackle contemporary issues of this kind.