The Science Curriculum Improvement Study has identified two main types of lessons: invention lessons, where the teachers introduce concepts, and discovery lessons in which children apply the concepts to new situations. The transcripts of tape recordings of the same sequence of four lessons, two invention and two discovery, of four teachers in the same school were analyzed in terms of question type and teacher reaction to responses or to her own questions. There was a difference in complexity of questioning pattern by the teachers across the four lessons, but the differences between individual teachers were more striking. The percentage of routine and cognitive-memory questions seemed to be influenced by the lesson being taught, but no t by whether it was a n invention or discovery lesson per se. When the lesson was largely demonstration, there were less routine questions and more cognitive-memory questions. About half the questions in all lessons were convergent, with few evaluative questions. Although there were few divergent questions in all lessons, there were more in the invention type lesson. There were definite differences between teachers in their reactions to responses, but these were not related to the type of lesson. (Author/AL)