Experiments With Soda & Mints

Using a bottle of soda and hard mints, you can demonstrate the phenomenon known as nucleation. The experiment was originally conducted with the Mentos brand of mint, which works well because of its pitted shell characteristics. Other brands can work as well, however, check them under a microscope to ensure that they have a pitted shell for the experiment to work. Nucleation is a physical reaction, not a chemical reaction.

Nucleation Demonstration

Remove the label from a bottle of cola, quickly insert one to three mints and give the bottle some space. There should be an energetic geyser-like reaction, causing the soda to burst out of the bottle. Due to the mass and bulk of this experiment it may be wise to conduct it outside. Given the right conditions, the geyser can easily hit the ceiling. Regular cola works best for this experiment, but you can also use a clear carbonated beverage so that the nucleation process can be viewed more clearly.

Nucleation Explanation

In nucleation in a carbonated liquid, carbon dioxide forms bubbles inside of the many pitted regions on the surface of the mint. Because there are so many microscopic defects in the surface of the candy, a vast number of bubbles form quickly and the effect cascades as each bubble rises, leaving space for another to form.

Adding Variations to the Experiment

There are quite a few educational variations that can be made to this experiment, such as adding a surfactant such as dish soap, which should amplify the geyser-like effects by lessening the surface tension of the liquid. You can also attempt to use different types of carbonated beverages and form hypotheses as to why some reactions are more energetic than others, such as the presence or absence of particular ingredients backed by data on such ingredients. Teachers who use these experiments in class can divide students into groups, charging each team to create the most energetic reactions. The groups will experiment with data such as the number of mints used, the amount of cola and even the size and shape of container used.