This theory, suggested by "Mythbusters," was confirmed by Tonya Coffey, a physicist at Appalachian State University, and published in the American Journal of Physics in Max Roman Dilthey is a science, health and culture writer currently pursuing a master's of sustainability science. Based in Massachusetts, he blogs about cycling at MaxTheCyclist.
The Effect of Temperature on Bubble Solution. How to Make a Realistic Erupting Volcano. How to make a "Volcano Experiment" Easy and Fun. Your Body On: Halloween Candy. Aside from the microscopic structures on the outside of the Mentos shells, there are several chemicals that make Coca-Cola explode in this way.
These chemicals are found in the shell itself as well as in the soda mixture, and they contribute to the formation of pressurised foam. Here are some of the chemicals that make up the shell:. These ingredients act as surfactants and help accelerate the release of carbon dioxide gas. Surfactants lower the surface tension between two liquids, a liquid and a solid, or between a gas and a liquid. So, when a Mento is dropped into some Coke, the acidity of the soda mixture quickly dissolves its shell, releasing the chemicals.
Their surfactant properties then lower the surface tension of the Coke, which breaks apart the water molecules and, in doing so, allows carbon dioxide bubbles to form more readily. With this in mind, the chemicals in Mentos also serve as foaming agents by facilitating the rapid release of CO 2 gas.
Various types of carbonated beverages react differently with Mentos: Seltzer water has the weakest reaction while, very specifically, Diet Cherry Dr. Pepper has the strongest reaction. This was demonstrated in an experiment that tested 15 types of carbonated beverages with Mentos. Each bottle tested had a two-litre capacity, and eleven Mentos were introduced to each bottle. They also compared reactions using other fizzy liquids such as caffeine-free and sugary colas, as well as soda water and tonic water.
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.
The carbon dioxide molecules collect on these places and form bubbles which rise to the surface. Make a Mentos-and-Soda Fountain!
First, make a tube for the Mentos. Cut a piece of paper so that it is as wide as a roll of Mentos. Open the pack of Mentos and place all of them in the tube. Now, make a Mentos-and-soda fountain! Slowly and carefully open a new bottle of Diet Coke. Place it on a flat area outside where it is OK to get wet with soda.
Bubbles and soda will quickly shoot out of the bottle in a high fountain.
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