Kinetic Modeling of and Effect of Candy Additives on the Candy–Cola Soda Geyser: Experiments for Elementary School Science through Physical Chemistry

When Mentos candies are dropped into a bottle of Diet Coke, a foamy fountain jets out of the beverage container. It has previously been argued that ingredients found in Mentos candies significantly enhance this fountaining effect. Other previous work has demonstrated that the kinetics of foam production can be quantitatively monitored using a device constructed from inexpensive, easily obtained materials. In the results reported here, students used this simple device to monitor the kinetics of foam production in the Diet Coke and Mentos experiment and to draw conclusions about the system. It was possible to model the kinetic data obtained using kinetic mechanisms that involve irreversible first-order steps. Furthermore, the data collected allowed students to acquire evidence that the kinetics of foam production appears to be unaffected by the presence of certain ingredients in candies and gums, in contrast to previous claims. Many of the protocols described herein can be carried out simply and inexpensive...