Determine the relative effectiveness of various commercial sunscreen lotions under laboratory conditions. Can serve to promote scientific investigation of consumer products. The experiments consist of allowing light energy to act upon a photosensitive chemical agent with the blocking of the light energy dependent upon sunscreen employed. After the exposure the amount of chemical conversion is measured and plotted as a function of the "Sun Protection Factor", SPF. Kit is designed for 24 students working in groups of 4. Grades 6-8.