We will describe an attempt to improve children's understanding of some basic concepts in mechanics starting firoman examination o[ their ideas of motion. Children's personal experience of the world colours their beliefs and explanations in science. A computer augmented curriculum w a s designed to promote conceptual change in the classroom. Twenty-nine twelve- and thirteen-year-olds, and their usual classroom teacher tried it out. T h e computer programs consisted of interactive simulations which allowed direct engagement with animations of real world scenarios in which pupils have control over forces and objects. W e demonstrated that this curriculum produced evidence of conceptual change. O u r findings have implications for the development of a more sophisticated view of conceptual change.