Abstract: This experiment delves into the common phenomenon of surface tension in everyday life. By systematically optimizing existing methods from the literature, we create solutions of different concentrations using a mixture of glycerol and water, with food coloring added to represent the varying concentrations. Due to the imbalance in evaporation gradient and surface tension, small droplets on hydrophilically treated glass slides exhibit behaviors such as “chasing” and “dancing”. These movements reflect a range of physical chemistry phenomena related to surface tension and evaporation. The experiment employs safe and readily available chemicals, with custom-made main devices, making it straightforward and comprehensible. With parental guidance, primary and middle school students, and even kindergarten children, can distinctly observe the chasing and fusion of droplets of different colors. This experiment is eco-friendly, safe, and visually appealing, which is beneficial for cultivating a strong interest in physical chemistry phenomena among the general public, especially primary and secondary school students.

Key words: Popular science experiment, Physical chemistry, Surface tension, Evaporation gradient, Droplets chasing