Crime scenes often contain broken glass from windows, cars, vases and numerous other glass items. Matching glass pieces with other glass pieces can reveal patterns that can help explain a criminal sequence. This activity utilizes safe chemicals and simulated glass to safely teach the principles of glass density analysis, a key technique used by criminalists. The flotation technique utilized in this lab will provide the hands-on experience students need to crystallize their general understanding of density. Students will also appreciate the complexity of glass analysis in crime scene investigations.