Why Do Diet Coke And Mentos Create Such Exciting Geysers?

Why does Diet Coke and Mentos create such exciting geysers? It is mostly caused by a process called nucleation, where the carbon dioxide in the soda is attracted to the Mentos. When this happens it creates so much pressure that the soda goes flying. So what speeds and slows down this reaction?
Some scientists are saying the primary cause of diet coke and mentos geyser is a physical reaction, not a chemical reaction. All the carbon dioxide in the soda is squeezed into the liquid and looks for a way out. Nucleation sites can be scratches on a glass, the ridges of your finger, or even specks of dust anywhere that there is a high surface area in a very small volume. The Mentos are sprayed with over 40 microscopic layers of liquid sugar. It covers the mentos with lots of nucleation sites. The mentos are also heavy enough to sink, they react with the soda all the way to the bottom. All that pressure has got to go somewhere and …show more content…
Diet Coke is also not as sugary and sticky. Bottled sodas are kept under pressure so that more carbon dioxide is forced out of solution and makes little gas bubbles. So, if you open a bottle of soda gently, you get a pleasant beverage. If you shake the can first, you disrupt the solution and the soda goes every where when you open it. If you add a big enough surfactant, you get a geyser. The two biggest factors affecting the geyser are the roughness of the candy used and the rate at which it sinks to the bottom of the soda bottle. Other factors that affect the growth rate or total number of carbon dioxide bubbles also change the geyser’s height, such as temperature and the original surface tension of the soda. Diet Coke makes a better spectacle than regular Coca-Cola because both aspartame and benzonatate (artificially sweetened drinks) lower surface tension more than sugar does.