This mixed-methods investigation compared the relative impacts of instructional approach and context of nature of science instruction on preservice elementary teachers' understandings. The sample consisted of 75 preservice teachers enrolled in four sections of an elementary science methods course. Independent variables included instructional approach to teaching nature of science (implicit vs. explicit) and the context of nature of science instruction (as a stand-alone topic vs. situated within instruction about global climate change and global warming). These treatments were randomly applied to the four class sections along a 2 x 2 matrix, permitting the comparison of outcomes for each independent variable separately and in combination to those of a control group. Data collection spanned the semester-long course and included written responses to pre- and post-treatment administrations of the VNOS-B, semi-structured interviews, and a variety of classroom artifacts. Qualitative methods were used to analyze the data with the goal of constructing profiles of participants' understandings of the nature of science and of global climate change/global warming (GCC/GW). These profiles were compared across treatments using non-parametric statistics to assess the relative effectiveness of the four instructional approaches. Results indicated that preservice teachers who experienced explicit instruction about the nature of science made statistically significant gains in their views of nature of science regardless of whether the nature of science instruction was situated within the context of GCC/GW or as a stand-alone topic. Further, the participants who experienced explicit nature of science instruction as a stand-alone topic were able to apply their understandings of nature of science appropriately to novel situations and issues. We address the implications of these results for teaching the nature of science in teacher preparation courses. (Contains 4 tables.)