Smartphone Schlieren

We present a schlieren system comprised of 3D printed optical mounts, a sub-$10 mirror, and a smartphone camera. The system is intended to make schlieren imaging accessible to K-through-12 students, educators, as well as hobbyists. In the manuscript, we detail the design of the system, provide source files for continued iteration, and show some example schlieren images and videos of a butane lighter, a jet of compressed air, and an electric stove.