While we were on vacation, we saw an episode that showed the combination of mentos and diet coke causing a bubbling geyser of beverage. (Sorry, I was unable to embed the video of their investigation, but here's the link.) The guys looked at the mentos candy and diet coke ingredients, one by one and figured out which ingredients caused the reaction. They did this by adding powdered versions of all the funky stuff in diet coke one at a time.
Now I have to say, I like my diet coke. A lot. But it kind of makes me wonder why phosphoric acid is in it- that stuff is used to prevent/remove rust in addition to flavoring colas. Weird!I'm not sure if I could wean myself off the stuff (although I will make sure not to eat mentos at the same time!). Does anyone know of a "natural soda" that would be as good as the old faithful?