How Sugar Affects Yeast Growth: A Cellular Respiration Experiment

Next Generation Science

This video provides a clear, step-by-step demonstration of cellular respiration using a classic science experiment involving yeast, sugar, and balloons. It begins by defining cellular respiration and providing the chemical equation: glucose + oxygen → heat + carbon dioxide + water. The narrator then sets up a comparative experiment using two bottles—one with just water and yeast (the control), and one with water, yeast, and sugar (the variable). The video visually demonstrates the scientific method in action. By capturing the reaction over time, viewers see the yeast in the sugar-fed bottle become active and frothy, eventually releasing enough gas to inflate a balloon attached to the bottle's top. The narration explains the biological mechanism happening inside: yeast cells are metabolizing the glucose, dividing, and releasing carbon dioxide as a waste product, which causes the inflation. This resource is highly valuable for visualizing invisible biological processes. It serves as an excellent anchor for lessons on cellular biology, chemical reactions, and experimental design (specifically independent vs. dependent variables). The clear contrast between the two bottles makes the abstract concept of gas production during respiration concrete and observable for students.