The Mentos - Cola Myth 
Actual bombs, gas expansion, and deadly explosions in the stomach can all be read about on the internet. The consumption of a bottle of Diet Coke and a Mentos mint is said to have cost the life of a 10 year old Brazilian school child. Supposedly, Alexander Mergenthaler, alleged professor at the chemistry institute of the University of Sao Paulo, is currently researching the chemical reaction that occurs through the combination of these two foods, to be exact Acesulfam-K, contained in Diet Coke and the not so specifically identified Mentos artificial flavoring, which produces a substance coined as Ta9V4. In reality, the entire thing is a farce: neither this substance, nor the professor, exist, and by no means is the enjoyment of Mentos and Diet Coke in combination a hazard to your health.
The Mentos - Coke fountain
This myth is grounded in an impressive experiment which can be carried out as followed: drop a Mentos mint into a carbonated beverage – Diet Coke suits itself particularly well – and a plume of cola, which can reach impressive heights with the proper preparation of a pipe on top of the bottle, bursts from the Coke bottle. This experiment should not be conducted in your own home, but is rather suggested to be carried out at a place where a massive spill of Coke won’t lead to a contamination of the surroundings. There is a whole series of videos about this on the internet, I find the cascade of 251 2-liter bottles of Diet Coke set off in domino fashion by 1506 Mentos mints by EepyBird (see right) to be the most impressive.
Carbon Dioxide in Soft Drinks – a meta-stable Situation
But what exactly goes on here? Carbon dioxide is dissolved in all soft drinks; an especially large amount (7 to 8 g/L, or 4 liters of carbon dioxide gas) in Diet Coke. Due to high amounts of sugar, the solubility of carbon dioxide is somewhat less in regular cola, making this experiment work best with Diet Coke.
As everyone knows from their own experience, gaseous carbon dioxide is released from these drinks over the course of time, a process that can be accelerated by shaking or warming up such drinks. At the same time, the discharge rate is proportional to the amount of available surface area on which the gas can escape.
The Mentos Catalyzer – No Chemistry!
In order for gas vapor to form and be released from the liquid phase, locations are needed to promote nucleation (the accumulation of many gas molecules). Rough surfaces are especially effective, as gas molecules loosely hold onto the bumps and cavities of these surfaces, allowing nucleation. There are many examples of this: a coin or cookie crumbs also make cola bubble. The effect is indeed not as great as that with a Mentos mint, though, as it has a particularly large amount of cavities on its surface. One thing is clear: for a change chemistry is not responsible, a purely physical process is at work here.
> > >Part 2 : Acesulfam-K and other artificial sweeteners - legitimate scpticism?
Related articles in German:
Sucralose_-_ein_neuer_Süßstoff | Ohne_Chemie...ist_alles_Nichts | Acomplie_-Wunderpille_bekämpft_Fettsucht
