Experiment 1: Diet Coke and Mentos
The small bottles definitely did not work as well as the big ones
Experiment #2: Elephant Toothpaste
It took a few tries to find the right bottle for this experiment. You needed something skinny to make the foam come out looking like toothpaste. This was one we could do a few times over and them we played with the foam. Definitely more fun than diet coke and mentos. But also a bit more dangerous.