Here’s a fun Google video of what happens when you put Mentos in soda (you might want to mute the sound). The video doesn’t explain how it works, but there’s an overview here “Mentos contain sugar, glucose syrup (more sugar), hydrogenated coconut oil, starch, gum arabic, an emulsifier and natural flavor. The gum arabic which makes Mentos chewy, cause the surface tension of the water molecules to break even more easily, releasing more carbon dioxide gas. This effect is enhanced by the fact that, as the candy dissolves, it forms nucleation sites — tiny pits on the surface of the mint where more carbon dioxide bubbles can form. When all this gas is released, it thrusts the entire contents of the bottle skyward, in an incredible soda blast.” Link to video.
Soda + Mentos = The Soda fountain