Despite the fundamental importance of plants to our very survival, student interest in plant biology is in decline as technology draws us further away from nature. Here we introduce "Plant Tracer" (http://www.planttracer.com), a Matlab-based program, which can quantify time-lapse videos of plant movement. We demonstrate that Plant Tracer can be used to distinguish altered movement qualities in the inflorescence (flowering) stem in the Arabidopsis "pgm-1" (phosphoglucomutase) mutant when compared to wildtype, providing a genetic platform for students to evaluate how plants sense and respond to gravity and circumnutation (the back-and-forth swaying of plant organs). We show that both gravitropism and circumnutation is diminished in the "pgm-1" mutant when compared to wildtype. In this way, "Plant Tracer" is a promising instructional tool for biology labs to quantify the genetics of plant movement using smartphones.