This post is co-posted with a new podcast episode! This is how the Mentos®-Diet Coke® Reaction works. On each Mentos® chewy mint, there are thousands of tiny pits called nucleation sites, where Carbon Dioxide bubbles can form. When the Mentos® hit the surface of the Diet Coke®, bubbles come up into the nucleation sites until the force pushing all of the bubbles upward is greater than the force pushing the Mentos® downward, shooting Diet Coke® into the air. Your Editor, Brovie.