Sarah paints, makes jewelry, and plays the trumpet in her school band. She would like to become a medical researcher someday, because she "enjoys learning about the human body."
During the harsh, dry Michigan winters, Sarah and her family try many different skin moisturizers. While preference is largely subjective, Sarah thought that she could objectively measure how well lotions add and retain moisture. She hypothesized that lotions with more oils would perform better.
A TV science show inspired Sarah to use gelatin as a substitute for human skin: it has a high moisture content, is safe and readily accessible, and can be easily weighed. She poured equal weights of gelatin into 13 petri dishes. She spread 2 tablespoons of 12 different moisturizers on the dishes and kept the last as a control. She weighed the dishes every day for a week and found that the control sample lost almost 97 percent of its weight, while the dish with the best-performing lotion lost only 1 percent of its weight. Her results demonstrated that products with more oil than water performed best.
