Resumen de Formation of a Water Ball in a Water Bottle to Learn the Chemistry of Surfactants
This paper reports a demonstration of a 90 min on-demand class where a chemical experiment is performed to educate nonscience majors on surfactants. First-year undergraduate students perform the water ball in a water bottle experiment at home and learn about the structure and properties of organic compounds in the demonstration. The experiment is very simple and conducted within a short time (10 min) using inexpensive starting materials (i.e., water, bottle, straw, and dishwashing liquid). The impressive phenomenon of this experiment is that an aesthetically pleasing sphere is produced, which has significant visual impact on the student and causes them to wonder why the ball appears. The instructor explains the chemistry of surfactants as hydrophilic and hydrophobic features. Another striking feature is the ring shape that appears once the water ball breaks. This add-on topic provides the opportunity to consider the dynamics of flow. Furthermore, taking advantage of the mysteriously thick appearance of the water ball shell, the instructor can briefly introduce the nature of light with an add-on mathematical exercise for the students. Students can thus experience chemical phenomena using household materials.
