Saving Your Students' Skin. Undergraduate Experiments that Probe UV Protection by Sunscreens and Sunglasses

Abstract

Recent scientific evidence suggests that chlorofluorocarbons have substantially depleted the ozone layer, the earth's primary filter for ultraviolet radiation. At the same time, medical evidence has accumulated which suggests that exposure to ultraviolet radiation is a major cause of prevalent human health disorders, including skin cancer and cataracts. For these reasons, consumer purchases of sunscreens and sunglasses, which provide protection from ultraviolet radiation, have soared, and manufacturer interest in improving these products has intensified. This article describes absorption spectroscopy experiments that illustrate the mechanism of action of sunscreens and sunglasses and that highlight the differences between different products. The experiments are well suited to incorporation into an undergraduate science laboratory and will expose students to absorption phenomena in a familiar context with substantial environmental and medical relevance.