The final word, I hope, on Diet Coke and Mentos
I was up late watching TV and I saw an episode of Mythbusters that I hadn’t seen before. It was done over the summer and it featured, yes you guessed it Diet Coke and Mentos. They answered a lot of the questions surrounding this fun little experiment and clarified for my why the B-day part coke geyser, didn’t geyser.
Okay first thing, it has to be Diet Coke and mint Mentos. I’ll get to the reasons in a second. I did use mint Mentos, but cheepo regular cola for the geyser and that’s why my geyser was a tad whimpy.
The question for the Mythbusters wasn’t if it worked, but how it worked. Clearly it had something to do with CO2 and the candy. So Adam and Jamie compared DC (Diet Coke) and soda water. The DC had a much bigger reaction to a single Mento than soda water, so it must be something other than just candy and CO2.
Adam gathered some of the component parts of DC, Aspartame, caffeine, potassium benzoate, citric acid, and phosphoric acid and tested each one in soda water. Turns out that Aspartame, caffeine, and potassium benzoate all react strongly with Mentos. Ah hah!
So what’s happening to get a ten foot geyser is a cascading reaction with the three components and the Mentos to release a lot of CO2 all at once. Great, but why. Nucleation. Nucleation is, like I’ve talked about before, the reaction between the surface of the object and the liquid to encourage the CO2 out. The rough surface of the candies gives the CO2 something to cling to and then release. Because the candies are heavy they sink to the bottom where they force the reaction in the greatest volume of liquid and giving the CO2 lots of space to push out … and hence the geyser!
So there it is. I need to use Diet Coke so I get the aspertame boost. I need to use mint Mentos for the maximum nucleation sites. I see another geyser in the future …
Oh the picture? That’s Keri Byron who did a spread for FHM on Mythbusters. Yep I think she’s a hottie.
Tags: Diet Coke Mentos, coke geysers, mentos coke, Keri Byron, Mythbusters
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