This study investigated whether participation in the Partnership for Research and Education in Plants (PREP), a long-term authentic plant research project, in conjunction with explicit verses implicit instruction can change high school students' conceptions of the nature of science (NOS). The participants included a total of 134 students comprised of three groups from 10 total classes over the course of two academic years. Participants in four classes (two each year) participated in PREP and received explicit instruction on NOS. Participants in four other classes (two each year) participated in PREP and received implicit only instruction on NOS. Additionally, two classes (one each year) of high-achieving freshmen participated in PREP and received explicit instruction on NOS. This third group was used as a comparative group to the other two groups, due to their high achievement in middle school math and science. The treatment for all three groups spanned 8 weeks and included participation in an authentic plant research project. An open-ended questionnaire (modified Views of Nature of Science-VNOS), in conjunction with semi-structured interviews, was used to assess students' conceptions before and after the intervention. Results showed that all three groups improved their conceptions of NOS equally. The high-achieving group began with significantly higher-scoring views prior to the completion of the intervention, and improved to the same degree as the other two groups. A comparison of the explicit group to the implicit only group showed that there was no significant difference in their improvement, as both groups improved equally. Implications for the teaching and learning of NOS are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]