Exploding Toothpaste Experiment

Adapted from: http://www.coolscience.org/CoolScience/KidScientists/h2o2.htm

Uses of Hydrogen Peroxide: http://www.naturallivingideas.com/hydrogen-peroxide-uses/

Hydrogen Peroxide is a very basic chemical. Its chemical formula is H2O2. It is essentially a water molecule with an extra oxygen bonded to it. Normally, this oxygen will react with other materials, resulting in H2O and O2. To quicken this reaction, we will use a catalyst, in this case, yeast.

However, as you can see, not everything worked out as planned. In some classes, the reaction was quite slow. In other classes, the bubbles came out nicely. What do you think caused these differences? What are some variables that I should control better?