I saw the video of the Bellagio-like fountains of Mentos and Diet Coke today. This is something that my son Max had tried to accomplish a few weeks back, and we were stumped as to how to get the Mentos into the soda bottle efficiently enough to get a good geyser. Fritz Grobe and Stephen Voltz described their techniques well enough for us to duplicate their method. Now I’m providing an illustrated guide of our process: