Mentos + 2 liter soda = explosion?
IT’S MICROSCOPIC SEED-BUBBLES! I’ve found that several chem references contain a widespread misconception: the (wrong) idea that bubbles can be nucleated by “roughness.” In fact, rough surfaces can only provide nucleation sites if the surface is dry. The actual nucleation sites are gas pockets trapped in the rough spots. They’re tiny bubbles. “Seed bubbles.” The nucleation sites for bubble formation are always just smaller bubbles. It makes sense if you think about it: to nucleate a condensing fog droplet we need a solid or liquid seed, and to grow a crystal we need a tiny solid seed crystal. To grow a bubble we need to start out with an existing gas/liquid interface: a tiny seed bubble. “Roughness” doesn’t do it. Neither do chemical additives. This “roughness” misconception is not so benign, since safety concerns involving explosive boiling are present. Especially important is safety involving the explosive boiling of microwaved coffee. If we believe in “roughness” and we don’t unders
