I need to do a project for my 8th grade science class. A classic, a model volcano. Now, i wanted to do something other than the "baking soda and vinegar" eruption, I wanted to do... Diet Coke and Mentos. Now, the mess has to be fairly small, but still do an explosion. I was thinking of using wither a 1 liter or 16-ounce bottle. How many Mentos should go in? like 3, or 4?