This mixture was first formulated by an American pharmacist, John S. Pemberton , in — though it was originally marketed as a panacea for common ailments. The original ingredients of Coca-Cola contained cocaine from coca leaves and caffeine-rich extracts from kola nuts. The present-day ingredients of Coca-Cola classic are a little different:. Diet Coke and Coke Zero react better with Mentos than regular Coke does because of the absence of sugar. A lack of sugar makes the soda mixture less viscous, given the presence of sweeteners, like aspartame, lowering the surface tension even more than usual.
This in turns means that the carbon dioxide gas is more rapidly released. The nucleation process is also faster, leading to higher gas pressure.
We can see how much better Diet Coke and Coke Zero react with Mentos just by looking at the experiment we showed earlier: both of these sugar-free sodas produced fountains that exceeded 2. So, in a nutshell or, more aptly, a Mentos shell , soda mixtures with more sugar in them are more viscous, making their reactions less powerful. All content published on the ReAgent. The blog, its authors, and affiliates cannot be held responsible for any accident, injury or damage caused in part or directly from using the information provided.
Additionally, we do not recommend using any chemical without reading the Material Safety Data Sheet MSDS , which can be obtained from the manufacturer. You should also follow any safety advice and precautions listed on the product label. If you have health and safety related questions, visit HSE. Contact Us. In the Diet Coke bottle the Mentos candy provides a rough surface that allows the bonds between the carbon dioxide gas and water to break more easily, helping to create carbon dioxide bubbles.
As the Mentos candy sinks in the bottle, the candy causes the production of more and more carbon dioxide bubbles, and the rising bubbles react with carbon dioxide that is still dissolved in the soda to cause more carbon dioxide to be freed and create even more bubbles, resulting in the eruption.
Because Mentos candies are rather dense, they sink rapidly through the liquid, causing a fast, large eruption. The crushed Mentos candies, however, are not as dense as the whole ones, which causes them to sink more slowly, creating a relatively small cola fountain, which should also leave more liquid in the bottle than the larger eruption with whole Mentos candies did. Cleanup Hose off any part of a building that was splashed with Diet Coke.
If you try this project with regular Coke, the eruption should still happen but its sugary content may make cleaning more difficult.
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Sign up for our email newsletter. Sign Up. Support science journalism. Knowledge awaits. See Subscription Options Already a subscriber? Create Account See Subscription Options. Continue reading with a Scientific American subscription. Subscribe Now You may cancel at any time. The results showed that Diet Coke created the most spectacular explosions with either fruit or mint Mentos, the fountains travelling a horizontal distance of up to 7 metres.
But caffeine-free Diet Coke did just as well, suggesting that caffeine does not accelerate the reaction, at least at the normal levels in the drink. Measurements of the pH of the Coke before and after the experiments showed that its acidity did not change, ruling out the idea that a simple acid-base reaction drives the fountains. Instead, the vigour of the jets depends on various factors that affect the growth rate of carbon dioxide bubbles.
The rough, dimply surfaces of Mentos encourage bubble growth because they efficiently disrupt the polar attractions between water molecules, creating bubble growth sites. Low surface tension also helps bubbles grow quickly. Measurements showed that the surface tension in water containing the sweetener aspartame is lower than in sugary water, explaining why Diet Coke creates more dramatic fountains than sugary Coke.
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