Four distinct plastics recycling projects created by middle school students emerged from a one-week long plastics recycling activity incorporated within a science, technology, engineering, and mathematics (STEM) residential summer camp at a research-intensive university. The plastics recycling activity was a project-based learning (PBL) activity facilitated by STEM experts in geometry, architecture, and materials science. Specific instruction involving mathematics and science concepts was provided to emphasize content-specific knowledge related to plastics recycling. A rubric was applied and used to determine evidence of learning manifested in participants' final presentations. Participants' final presentations demonstrated mixed results in terms of student learning outcomes, but indicated that campers demonstrated a clear sense of social environmental awareness and responsibility toward recycling plastics.