Abstract: This study (a) assessed the in¯uence of three history of science (HOS) courses on college
students' and preservice science teachers' conceptions of nature of science (NOS), (b) examined whether
participants who entered the investigated courses with a conceptual framework consistent with
contemporary NOS views achieved more elaborate NOS understandings, and (c) explored the aspects of
the participant HOS courses that rendered them more ``effective'' in in¯uencing students' views.
Participants were 166 undergraduate and graduate students and 15 preservice secondary science teachers.
An open-ended questionnaire in conjunction with individual interviews, was used to assess participants'
pre- and postinstruction NOS views. Almost all participants held inadequate views of several NOS aspects
at the outset of the study. Very few and limited changes in participants' views were evident at the conclusion
of the courses. Change was evident in the views of relatively more participants, especially preservice
science teachers, who entered the HOS courses with frameworks that were somewhat consistent with
current NOS views. Moreover, explicitly addressing certain NOS aspects rendered the HOS courses
relatively more effective in enhancing participants' NOS views. The results of this study do not lend
empirical support to the intuitively appealing assumption held by many science educators that coursework
in HOS will necessarily enhance students' and preservice science teachers' NOS views. However, explicitly
addressing speci®c NOS aspects might enhance the effectiveness of HOS courses in this regard. Moreover,
the study suggests that exposing preservice science teachers to explicit NOS instruction in science methods
courses prior to their enrollment in HOS courses might increase the likelihood that their NOS views will be
changed or enriched as a result of their experiences with HOS. ß 2000 John Wiley & Sons, Inc. J Res Sci
Teach 37: 1057 ± 1095, 2000