Coca-Cola Fountain and Mentos

In 1980, Wint-O-Green and Soda ^[3] tablets were used to create such a fountain. Dragees were strung on a thin brush for cleaning smoking pipes, which was then placed in a soda to cause the formation of a fountain ^[3] . In the late 1990s, the manufacturer Life Savers increased the size of dragees produced, as a result of which they no longer fit in the neck of a soda bottle ^[3] . Researchers, however, soon discovered that the Mentos dragee when it enters the soda bottle causes the same effect ^[3] .

Lee Marek and his Marek's Kid Scientists performed an experiment with diet Coca-Cola and the Mentos dragee on the late show with David Letterman in 1999 ^{[2] [4] [10]} . In March 2002, Steve Spengler, a scientist and teacher, demonstrated the same experience on KUSA-TV , an NBC affiliate in Denver , Colorado. ^[11] The experiment with the Mentos geyser became an Internet sensation in September 2005 ^[6] . He also became the subject of research in one of the episodes of the television series " Legend Destroyers " in 2006 ^{[10] [12]} . Spengler signed a licensing agreement with Perfetti Van Melle , the manufacturer of Mentos, after the invention of a device made to simplify the task of placing Mentos in a bottle and to achieve greater power as a result of the fountain ^[13] . The Amazing Toys , Spengler's toy company, released a toy in February 2007 called the Geyser Tube ^[14] . In October 2010, a record for this experiment was recorded in the Guinness Book of Records : at an event organized by Perfetti Van Melle in the SM Mall of Asia shopping center in Manila , Philippines , 2865 similar fountains were arranged simultaneously ^{[15] [16]} .

The structure of the Mentos pellets is the main reason for the “eruption” of the jet due to areas with heterogeneous nucleation ^{[3] [16] [17]} . The surface of the Mentos mint dragee is covered with many small holes that increase the surface area available for the reaction (and therefore the amount of reagents capable of reacting with each other at a specific point in time), thereby creating carbon dioxide with the formation of bubbles with speed and the amount necessary for effusion in the form of a "jet" ("geyser", "eruption") ^{[3] [12] [17]} . This hypothesis received additional support when rock salt was used as the “starting transition” to the reaction. Tonya Koffi, a physicist at Appalachian State University in Buna, North Carolina, has confirmed that the rough surface of the Mentos tablet helps speed up the reaction. Coffey was also able to find that aspartame , used in diet Coca-Cola, reduces surface tension and enhances the reaction, while caffeine does not accelerate its course. The reaction with the “eruption” is feasible using a regular or dietary cola, although dietary cola is used more often to simplify the washing of splashes of sweet soda ^{[18] [19]} .

After placing the mint dragee in a drink, bubbles form around the surface of the dragee, which rush to the surface of the liquid ^[3] . In addition, the density of Mentos is greater than the density of soda, which leads to the immersion of the dragee on the bottom of the vessel ^{[3] [12] [16]} . These two factors combined create an “eruption” of soda ^{[3] [12] [16]} .

Potassium benzoate , aspartame and gaseous carbon dioxide (contained in the dietary cola), in combination with gelatin and gum arabic (Mentos ingredients), together act as emulsifiers and contribute to the formation of a large amount of foam ^{[10] [12] [16]} .

• Solubility

• Baur, John E .; Baur, Melinda B. The Ultrasonic Soda Fountain: A Dramatic Demonstration of Gas Solubility in Aqueous Solutions (Eng.) // Journal of Chemical Education : journal. - 2006 .-- April ( vol. 83 , no. 4 ). - P. 577-580 . - DOI : 10.1021 / ed083p577 .
• Anne Marie Helmenstine. How To Make a Mentos & Diet Soda Chemical Volcano Eruption . About.com (December 5, 2014).