After taking in background information on teeth, marble, eggshell, and fluoride, chemistry aces design an experiment. Their goal is to demonstrate whether or not fluoride has a similar effect on marble or eggshell as it does on tooth enamel. Although there are chemical reactions involved in the activity, the intent is to provide practice designing and revising a scientific inquiry. What makes this lesson stand out is the unique topic and the well-written instructor notes and student directions.