Soda geyser
[3] Steve Spangler's televised demonstration of the eruption in 2005 became popular on YouTube,[4][5][6] launching a chain of several other Diet Coke and Mentos experiment viral videos.
[7][8] Experiments carried out at altitudes ranging from below sea level in Death Valley to the summit of Pikes Peak have demonstrated that the reaction works better at higher elevations.
At the end of the 1990s, the manufacturer of Wintergreen Lifesavers increased the size of the mints, and they no longer fit in the mouth of soda bottles.
[17] In October 2010, a Guinness World Record of 2,865 simultaneous geysers was set at an event organized by Perfetti Van Melle at the SM Mall of Asia Complex, in Manila, Philippines.
[18] This record was afterward beaten in November 2014 by another event organized by Perfetti Van Melle and Chupa Chups in León, Guanajuato, Mexico, where 4,334 Mentos and soda fountains were set off simultaneously.
[10] When the pressure is released from a soda bottle upon opening it, dissolved carbon dioxide can escape into any tiny bubble located within the beverage.
Mentos candies contain millions of cavities, roughly 1-3 μm in size,[26][10] that remain unwetted when added to a soda.
Thus, adding Mentos candies to a carbonated beverage introduces millions of nucleation sites into the drink, which allows for degassing that is rapid enough to support a jet of foam out of a bottle.
The physical characteristics of Mentos (surface roughness) have the effect of drastically reducing the activation energy for carbon dioxide bubble formation so that the nucleation rate becomes exceedingly high.
[1][15][18] Tonya Coffey, a physicist at Appalachian State University, suggested that aspartame in diet drinks lowers the surface tension in the water and causes a bigger reaction, but that caffeine does not accelerate the process.
[21] Furthermore, it has also been demonstrated that addition of certain concentrations of alcohol (which lowers surface tension) to carbonated beverages decreases fountain heights.
