This article describes a two-day optics laboratory activity that investigates the scientific phenomenon of reflection, which students are generally familiar with but usually have not studied in depth. This investigation can be used on its own or as part of a larger unit on optics. This lesson encourages students to think critically and mathematically about the data they collect and allows them to develop a model on their own. It addresses scientific and engineering practices identified in the "Next Generation Science Standards" (NGSS Lead States 2013), especially the practice of Analyzing and Interpreting Data. It also addresses the "Common Core State Standards," Mathematics (NGAC and CCSSO 2010), which emphasize mathematical modeling and the application of mathematics to the real world.