if you wanna know the reaction between mentos and diet coke all you would have to do is search on google video or youtube Mythbusters and pick the diet coke and mentos episode they did this experiment and they thought it is quite cool and they also did some other experiments with bubbles and stuff.
Yeah, the Mythbusters got it narrowed down pretty darn well. They even established a world record by creating the largest mentos-and-coke-induced-fountain ever. It was a combination of both certain ingredients in diet coke and mentos. They simply extracted most of the ingredients from a diet coke, and put them in separate bottles,pulling the old "Sherlock Holmes test of elimination". They concluded that a few ingredients were the cause of the massive reaction, but I can't say for sure which ones. But as mentioned before, it's also because of nucleation. When zoomed into, a mentos has the surface of a golf ball, with little craters in it. A chain reaction from millions of these craters is triggered when cast into coke, causing the ray of water to burst from the bottle.
It does take a certain brand, and the authentic mentos though, and a single mentos can be sufficient. The Mythbusters enhanced the effect by adding an extension on the bottle that would narrow the ray, thus increasing power, causing the coke to actually burst up for quite a height. (it blew over their workshop)


