The Mentos and Diet Coke reaction creates a foamy geyser due to a physical reaction where the rough surface of the candy provides nucleation sites for carbon dioxide bubbles in the soda to rapidly form and escape, forcing the liquid out in a powerful eruption, with Diet Coke preferred for being less sticky. To do it, drop several Mentos into a 2-liter bottle of room-temperature Diet Coke and quickly step back, letting the candy's surface and quick drop speed up the release of trapped CO2 gas.
After watching an episode of Mythbusters, I learned I had to try this at home. Next time you have a group of friends over try it out. An eruption of fun will happen. Check out the video below for even more info.....
