The aim of this study is to assess prospective teachers' views of some aspects of the nature of science (NOS) and the effects of a "Science, Technology and Society" (STS) course embedded with scientific investigation (SI) on these views. A questionnaire consisting of 13 items was given to 212 prospective teachers enrolled in a STS course before and after teaching. During the semester, participants were engaged in a specially designed pilot SI combined with explicit NOS instruction. Majority of the participants held traditional views of the target NOS aspects at beginning of the study. After the course there were significant changes in the conceptions of prospective teachers in majority target aspects of NOS as the results of a Sign test indicate. We suggest that the more suitable SI, performed in an active learning environment, related to target aspects of NOS must be selected to develop the more constructivist views about the NOS. (Contains 4 tables.)