ABSTRACT
One important way of describing the teaching of science in schools is as a process whereby students reconstruct their understandings in undergoing conceptual change. How to help teachers to promote conceptual change in an effective way in their classrooms is now a central concern of research groups in a number of countries and reflects the way curriculum development is being understood and approached. It is in contrast with the forms of curriculum development that took place in the 1960s and 1970s in which project teams outside schools developed and promoted a course and a package of related materials.
