The introduction of chemical concepts through concrete examples and interest-arousing demonstrations and activities is well accepted as an engaging and effective pedagogical method (Ealy and Ealy 1995; Gilbert et al. 1994; Katz 1991; Shakhashiri 1983- 1992 ). However, there is a lack of demonstrations and activities that can be used to engage students in learning organic reaction mechanisms. This article describes a colorful and engaging demonstration that was developed and used to engage students and lead them to an exercise that provides them with additional practice writing mechanisms. The demonstration is based on the changes in structure and color that occur in the dye molecule of roses with changes in pH.