The basic idea is this: We first mixxed 12% hydrogen peroxide with some liquid soap. We then add a catalyst (Yeast mixed with water) to make the hydrogen peroxide break down really quickly. Hydrogen peroxide breaks down into oxygen and water. There's a lot of oxygen trapped in peroxide, so this rapid decomposition results in lots of oxygen that needs to quickly push out of the container. As the peroxide breaks down, the soap that was mixed in will also combine with the water (from the break down process), and turn into foam. The oxygen gushing out is what makes the soap bubbles move. We added some food coloring which makes the resulting column of foam that gushes out look even more like toothpaste.