Expert: George Maxwell - 7/17/2007

Question
Today a friend told me that somewhere in Texas (I think) a large crowd gathered together with Pepsi bottles.  They added something to the Pepsi that caused the bottle contents to geyser up into the air.  What is the ingredient they added?  Or is this story bunk?

Many thanks for your very kind insight.


Answer
Hi, and thanks for your question.

This is a great demo / experiment, and works with most fizzy drinks. The other ingredient(s) are Mentos, those small minty candies. Mentos are covered with lots of little cracks on the surface so when you put them in the cola, they disturb the carbon dioxide gas that is dissolved in the liquid drink and cause it to escape as a gas. The escaping gas froths up the liquid, and (if enough gas is released) this froth has enough force to shoot out of the bottle, several feet up.

Hope this helps, but let me know if you need any more information.

Thanks again