The Chemistry of Henna: A Module for High School Students

Here we present a hands-on module for high school students to explore the chemistry of henna dye. This lesson is affordable, accessible, adaptable, and engaging for students. In this lesson, students learn how henna paste is derived from the henna shrub, discuss the chemical structure of the main dye component lawsone (2-hydroxy-1,4-naphthoquinone), apply the henna paste to their skin, and discuss the darkening of the dye over time as a result of an oxidation reaction. Through understanding the chemistry of henna, students are encouraged to consider the influence of chemical reactions in their daily lives. This module also promotes diversity and inclusion in science by increasing the representation of non-Western cultures in the chemistry curriculum. In this work, the module is presented in detail, and student reactions are discussed.