The Science Behind Why Mentos Fizzes When Put In Soda

The magnificent eruption after dropping Mentos into America's favorite soda, Coca-Cola, is a spectacle to behold. This impressive fountain of sugary liquid, which became an internet sensation in 2006, is fueled by an intricate science that reaches far beyond school science fairs. As opposed to chemical processes like the Maillard reaction and caramelization, both of which entail a change in the composition of the reactants, this bubbly explosion from the bottle is actually a physical reaction. This means that the chemical makeup of the parties at play remains unchanged, similar to when hot oil splatters on a stove when water makes contact with the hot surface of the pan.

The impressive soda volcano is spurred by the surface properties of Mentos and the carbon dioxide in the soda. The gas, which is dissolved under pressure, is what gives the soda its characteristic fizz. For the magnificent eruption, carbon dioxide needs to be released from the liquid, and this process needs external help. This is where Mentos works its tricks — it's unassumingly smooth surface is actually dotted with minuscule pits and grooves. These tiny bumps, basically invisible to the naked eye, play a crucial role in breaking the bonds between the gas and the liquid soda at multiple sites across its surface, triggering the rapid, bubbly release of carbon dioxide gas.

While the Mentos and Coke phenomenon is well-known, would the same physical reaction ensue with other sodas? The simple answer is yes, you can use any kind of pop to elicit a fountain reaction. Interestingly, the type of drink used can affect the magnitude of the reaction. Less viscous options like diet sodas, which typically contain artificial sweeteners, tend to yield more enormous eruptions. The low viscosity allows the carbon dioxide to escape more easily, hence resulting in a larger reaction. Additional ingredients in the soda can also impact how easily the gas is released. Similarly, other candies could also be used in this experiment, as long as they're heavy enough to drop into the pop and their surface has the microscopic bumps to instigate the rapid release of carbon dioxide. Playing around with different diet sodas (with caution of course) is a fun way to get kids excited about science!

In addition to offering an entertaining spectacle, this physical reaction offers a wealth of information for scientists to study scientific processes like nucleation — the first step in any phase transformation. So the next time you are inspired to tap into your inner researcher, (and maybe indulge your sweet tooth), grab some sodas and candies and enjoy their volcanic eruptions. Take a moment to appreciate all the scientific magic that happens outside the realm of our naked eye.