“…With the development of cheap and reliable audio-visual aids, such as tapeplayers and film-and slide-projectors, together with other reprographic technology, it seemed to many that the lecture might well be replaced with audio-visual presentations, combined with 'handouts' of lecture notes and, perhaps, appropriate problem-sheets or other exercises; self-directed learning seemed to be the way forward (Aylward and Barclay 1970;Hills 1976). In fact, self-paced instruction is still an ideal pursued by some in university science education (Srivastava 1989). Science may lend itself particularly well to this form of teaching, where there are many links between topics (Davies 1976), although the best method of pacing for problem-solving capability seems likely to involve a mixture of teacher-paced and student selfpaced instruction (Davies 1977).…”