We now know the effect of altitude on classic “Diet Coke and Mentos“ fountain

Enlarge / A well-coordinated Mentos-and-Diet-Coke explosion filmed in slow motion for The Slow Down Show in 2013. (credit: YouTube/The Slow Down Show)

Back in 2006, Fritz Grobe and Stephen Voltz-the self-described mad scientists behind Eepybird-ignited an Internet sensation with their viral video of an elaborate version of the Diet Coke and Mentos fountain experiment, recreating the choreography of the Bellagio's world-famous fountain display in Las Vegas. The underlying physics and chemistry of the fountain effect is well-known.

But an intrepid pair of scientists at Spring Arbor University in Michigan wondered whether altitude, and associated changes in atmospheric pressure, would have any measurable impact on the intensity of the foaming fountain and performed a series of experiments to find out. They reported their results in a recent paper in the Journal of Chemical Education. The upshot: If you really want to get the most foaming action for your buck, conduct the Diet Coke and Mentos experiment at high altitudes.

Grobe and Voltz didn't invent the basic demo. That has been around since at least the 1980s, although originally creative science teachers used Wint-O-Green Lifesavers threaded onto a pipe cleaner to induce the fountains of foam in soda bottles. In 1990, the size of the Lifesavers changed and were too big to fit into the bottle mouths. So science teachers switched to Mint Mentos candy to achieve the same effect.

Read 11 remaining paragraphs | Comments