Sugar vs. artificial sweetener

In an interesting twist on the tried and true yeast experiments, students devise an experiment to try to understand how small differences in chemical structures (sugar vs. artificial sweeten... See More

In an interesting twist on the tried and true yeast experiments, students devise an experiment to try to understand how small differences in chemical structures (sugar vs. artificial sweeteners) affect yeast metabolism. In contrast with some other experiments in this book, the structure of the experiment encourages more inquiry. Unfortunately, student groups perform experiments with either sugar or artificial sweetener, so there is little experimental control. I'm pretty sure this activity will be a hit with the students; I have done a similar activity with Girl Scouts, and it was very popular. I might suggest that frozen juice concentrate be used instead of squeezed blueberries; it would simplify the process greatly. Students might even choose to compare various types of juice, like apple, orange, pineapple, etc. as an extension. I would also suggest the use of champagne yeast, which is more successful at room temperature, and has a better flavor for the final product. It is easier to control the amount of alcohol production as well, because it metabolizes more slowly. Once the product is finished, the process is virtually stopped by storing the product in the refrigerator. Champagne yeast can be easily (and relatively cheaply obtained through a variety of sources. A solid beginning, with great potential with a few tweaks.