Experi-Mentos

A few weeks ago I was in England chatting with an engineering client over afternoon tea and he blurted out "Is it true that Mentos candy and Extreme Diet Coke react to create a geyser?" I had no idea what he was talking about until this morning when I happened across this video: . James Mack, an assistant professor of chemistry at the University of Cincinnati, theorizes that emulsifiers in Mentos break the surface tension of the water around the carbon dioxide bubbles in the soda. The candy tablets also provide nucleation sites on the surface - microscopic nooks and crannies that help carbon dioxide bubbles form and escape explosively. Although this phenomenom has been known for years, it seems to be coming to a head (pun intended!) just in time for USA's Independence Day celebration this year. It may make a nice fire extinguisher for the grass fires ignited by the firework embers and cast-off sparklers.

*(Source: "Mentos, Diet Coke put the pop in experiment" by Lauren Bishop, Cincinnati Enquirer, July 1, 2006.)