A Student-Built Flatness Gauge to Determine if a Fitness Center Employs Thinning Mirrors

Fitness centers and retail stores have often been accused of using "thinning" mirrors to enhance the images of their clientele. In this paper, the authors build a flatness gauge and use it to measure the curvature of the mirrors at a local fitness center. From these measurements, the image enhancement properties of the mirrors can be determined. The mirrors are found to be thinning, widening, and neutral with no apparent intent in their use or placement.