The merits of three approaches (explicit, reflective and implicit) to Nature of Science (NOS) teaching and learning in the context of a summer research experience on high school student participants' NOS ideas were explored in this study. The effectiveness of explicit over implicit approaches has been demonstrated in school contexts, but less empirical evidence exists regarding the comparative merits of these approaches when the practices that learners engage in are highly authentic in terms of their alignment with professional science and the context where they take place. The Authentic Experiences in Science Program (AESP), a summer program at a major research university, offered a unique context for an investigation of these issues. In the AESP, high school students worked for an extended period of time in a research laboratory on an authentic research project accompanied by out-of-laboratory seminars. A modified form of the Views of Nature of Science (VNOS) Questionnaire was administered to 30 participants of the AESP at the beginning and again at the end of the program. Additionally, six participants experiencing one of the three approaches were interviewed and observed as they participated in laboratory research. Results revealed that the explicit approach was generally more influential in this context. However, some students experiencing one of the other two approaches did exhibit changes in NOS understandings, and these changes seemed to be associated with favorable dimensions of the laboratory placements. These results support the argument that engaging students in highly authentic forms of scientific and engineering practices can be influential as a context for reflecting on NOS. Our results also speak to the power of explicit approaches to NOS teaching and learning when accompanying learner involvement in highly authentic science and engineering research.