There are few examples of NGSS specific projects at the high school level, particularly those linking chemistry and engineering practices. Further, there are few studies that provide concrete examples of how such projects can support students' submicrorepresentations (SMRs). This study reports on the implementation of an NGSS-aligned technology-supported desalinator project to improve the SMRs of 173 high school chemistry students from underrepresented backgrounds. Research methods included pre/post tests, student questionnaires, and observations. The use of the technology-supported project produced significant student learning gains for a number of pre/post items, but also illustrated areas for improvement in the design of the project. Findings on students' views of project-based learning and the use of technology to support their learning are also presented.