1. Put hydrogen peroxide and soap solution into a bottle.
2. Add food coloring (optional).
3. Mix yeast with water and pour it in the bottle to get a montrous foam.
As always feel free to experiment and do your own variations on the experiment/project. Try using different shaped bottles with different shaped openings. Add any chemicals that you think would add to the experiment. Use any combination of food coloring. Put something above the bottle to have the mixture try to hit it. The more hydrogen peroxide you have and the more concentrated it is the better. Experiment with different kinds of soaps and yeasts.