Next Generation Science Standards (NGSS), with new emphasis on engineering, reflects broadening definitions of scientific and technological literacy. However, engaging in science and engineering practices is necessary, but insufficient, for developing technological literacy. Just as robust scientific literacy includes a deep understanding of the nature of science, a robust technological literacy includes a deep understanding of the philosophy and nature of technology (PNOT). Related to PNOT, NGSS makes clear students should understand: (1) "how new technologies can have deep impacts on society and the environment, including some that were not anticipated"; (2) "all human activity draws on natural resources and has both short- and long-term consequences, positive as well as negative"; and (3) uses and limitations are "driven by individual or societal needs, desires, and values." Such outcomes move technological literacy away from simply using technology toward a more critical technological literacy. A critical technological literacy requires engagement with PNOT. This article describes a water purification activity used with eighth graders as a way to engage students with PNOT ideas while engaging in scientific and engineering practices (e.g., designing solutions). The authors also used this activity as a way to engage students with NGSS Disciplinary Core Ideas (DCIs) ESS3.A and ESS3.C as well as performance expectation MS-ESS3-3. For clarity, they have not discussed the development of science concepts in this article and have focused on the technology and engineering understandings that might be addressed through the activity. Yet, when teaching this activity to students, the authors spend significant time drawing their attention to and supporting their development of science ideas (Table 1). Importantly, the activity described is an exemplar, and the PNOT ideas described could be used during many other activities (e.g., egg drop, mousetrap car, lab designs, balloon rockets, bridge building, etc.) even if they don't have three distinct phases. Before describing the purification activity, some foundational ideas in the PNOT as background are briefly explored.