Inquiry-Based Experiments with No-Mess Markers

A previous article in this Journal focuses on “No-Mess” coloring products that utilize the chemical reaction between colorless leuco dyes and zinc ions, which act as Lewis acids ( J. Chem. Educ. 2022, 99 (6), 2364−2371). This reaction causes the leuco dyes to become colored. There are two main types of No-Mess marking systems. The first type includes markers containing leuco dyes that become colored upon contact with zinc ions embedded in marking paper. In the second type, the system is reversed. The markers contain zinc ions that activate leuco dyes embedded in the paper. These products offer new opportunities for guided and open inquiry-based investigations. This paper reports that solutions of zinc ions develop the color of leuco marker dyes to a degree comparable with commercial systems. While solutions of other metal ions also induce this color change, they do so to a lesser extent. Therefore, using zinc ion solutions allows for experiments and demonstrations with No-Mess marking products to be more visually stimulating than those previously reported.