National Standards for Grade Levels 6-9
 
Introduce students to the study of cosmetic chemistry as they perform physical, chemical, and cost analysis on hand lotions to evaluate the best product value. Students learn about the oil phase and the water phase used in creating lotions. The oil phase contains a variety of organic liquids such as fatty acids, lanolin, and other oils which have very low solubility and require emulsification during manufacture. The water phase includes such ingredients as glycerin, triethanolamine, antibacterial agents and fragrance. While learning the functions of various lotion components, students learn about hydrophilic and hydrophobic characteristics of molecules, emulsifying agents, and colloidal emulsions. In four separate experiments, students evaluate several lotions for percent solids, pH, density, and relative viscosity. They use this data to give a subjective rating of hand lotion effectiveness. Experiment 5 is an optional extension activity in which students formulate their own hand lotion. Includes a formula and instructions for making your own hand lotion (materials not included). Ideally taught as guided inquiry/qualitative analysis. Designed for 24 students working in groups of four. Allow 2 to 3 hours of lab time. Required but not included: 1 liter ethanol, hot plate or heat lamp, test tubes, stopwatch, and five different hand lotions for evaluation.