In this activity, students simulate a lactose tolerance test, similar to the one shown in the short film The Making of the Fittest: Got Lactase? The Co-evolution of Genes and Culture, to determine which samples contain the lactase enzyme.

To simulate measuring glucose in patient blood samples, students combine synthetically manufactured “patient intestinal fluid samples,” made of either water or a lactase solution, with milk, and then measure the amount of glucose produced in the solutions over time. Students work in pairs to collect, analyze, and graph their data to determine which “patients” are lactase persistent (lactose tolerant) and lactase non-persistent (lactose intolerant).