In this Activity, students dye fabric squares with two plant dyes: aqueous extracts of tea leaves and of marigold flowers. They investigate how the addition of iron to a dye bath affects the resulting color and fastness of the dyed fabrics and observe that the type of fabric affects the results. This Activity can accompany a discussion of the impressive array of chemicals produced by plants. Students can learn that the different appearances and textures of fibers are due to differences in chemical structures. The importance of intermolecular forces in the dyeing process can be demonstrated.
Jennifer E. Mihalick and Kathleen M. Donnelly, J. Chem. Educ. 2007, 84, p96A.