What causes Coke to explode when Mentos are added to it? One would think that there must be a chemical reaction that causes the Coke and Mentos reaction to be so attractive and satisfying. It’s actually not chemical! Let us dig deep into the experiment to understand why it’s not a chemical reaction.
The carbonated drinks’ fizz comes from carbon dioxide added to the bottles at high pressure. 2-liter Diet Coke contains around 12-15 grams of dissolved carbon dioxide. The gas tries to escape and form bubbles around any irregular surface, called a nucleation site. Mentos also have nucleation sites because they are not as smooth as they appear. When added to Coke, the dissolved gas pushes the liquid out of the container at a super-fast speed in the form of bubbles. The candies simply catalyze the release of gas from the Coke bottle. Therefore, the chemical reaction between Coke and Mentos, in reality, is a physical reaction.
No matter how messy or sticky the experiment is, there are only two ingredients required to make this geyser. One bottle of 2-liter fizzy drink, preferably Diet Coke, and Mentos are needed in an adequate quantity to give a spectacular reaction. For a 2-liter bottle of Coke, at least five Mentos are good enough. Moreover, all Mentos must be added to the drink simultaneously, giving each of them equal time to create an effect. As Mentos candies are dropped into the Coke bottle, there is an explosion seconds later, and a “Mentos Coke Fountain” goes high up in the sky.
Remember growing up with the advice that eating Mentos while drinking soda can burst a person’s stomach? Actually, it’s not that dangerous because most of the carbonation is released as a person drinks the soda. The pressure is lower and carbon dioxide does not nucleate. However, kids are not advised and should not do such a thing, as their stomachs are not powerful enough to absorb this physical reaction.
In easier words, Coke contains carbon dioxide, which gives the drink its fizziness. As a Mentos candy is dropped inside the bottle, the carbon dioxide molecules attach to it. In addition, the tiny pores on a larger surface area of Mentos ultimately speed up the release of the gas, which creates bubbles that rise to the surface and push the drink, eventually resulting in a blast.
The highest recorded explosion has been of Mentos and Diet Coke when the fountain touched up to 10 meters. Most people believe that the more Mentos are added to Coke, the bigger and higher the eruption will be. However, the number of Mentos that will make a difference is limited. Through various investigations, it has been deduced that seven Mentos are the max.