This web page contains a curriculum unit that explores the effect of nano-powders in sunscreen. The lessons focus on absorption and scattering of light, size and scale, ultraviolet light properties, and light reflection. It culminates with an ad campaign project for marketing a better sunscreen. Teacher resources include a syllabus, lesson plans, a pretest and post-test, extensive background information, Power Point lecture materials, student guides/handouts, and cost-free animation software that allows users to model chemical and nanoscopic processes. The materials were developed in a modular fashion to enable use for a short classroom introduction or a two-week experiential learning project. The materials were developed by NanoSense--an NSF-funded project to promote the teaching of nanoscale science at the high school level.