Practical Chemistry of Long-Lasting Bubbles

In this report, an experiment is described in which high school students investigate long-lasting bubbles of their own design. The features of the soap bubbles change depending on their chemical composition. To investigate the students’ original bubbles, the chemical structures and features of the ingredients are considered when choosing the detergent, polymer, and other chemical components. Soap bubble containing sucrose, sodium alkyl ether sulfate (AES)-detergent and poly(vinyl alcohol) (PVA) (or partially hydrolyzed poly(vinyl alcohol) (PVAAc)) often maintains a spherical shape on various solid surfaces, including concrete, asphalt, tile, and grass after landing. Students hypothesize that the low surface tension of the long-lasting bubble is not the sole reason for its long lifetime on various solid surface. The mechanism behind the extended lifetime is discussed through experiments involving the surface tension and lifetimes of the bubbles under various humidity conditions. Students encounter basic chemistry through the experiment, which can be adopted into the chemistry curriculum.