Incorporating authentic engineering practices into educative experiences in elementary school has the potential to positively impact student consideration of STEM careers and increase student self-efficacy in later engineering study. Additionally, as students move from primary to secondary grades, their interest in STEM topics tends to decline. To that end, teachers and researchers at Chaparral Elementary facilitated an independent engineering fair project to engage students in authentic practices of engineering to solve a self-identified problem with a designed or improved solution. We investigated how students’ perceptions of science and engineering were affected by their engagement in the practices of engineering through a two-week long independent engineering fair project. Data sources for the study include student surveys, researcher qualitative memos, informal student interviews, and student presentations. Our findings indicate that as students engaged with their independent engineering projects, their understanding of science as a tool for explaining the natural world improved and their perceptions of science and engineering and themselves as scientists and engineers was positively impacted.