Abstract
Piagetian theory predicts that group work between children whose initial understanding differs will be beneficial to conceptual knowledge in physics. If correct, this prediction offers reassurance to primary school teachers who are currently charged with conveying physics to children with a disparate range of background skills and knowledge. It is particularly reassuring given current attempts to integrate special needs children into mainstream schools. Recognising this, the paper starts by summarising three studies which investigate whether the prediction is, in fact, correct. Although the studies have a consistent (and encouraging) message as regards differing conceptions, they raise a number of questions about the optimal group design. These questions led to two further studies which are also summarised. Finally, the paper will relate all five studies to the issue of special needs.