Can you believe there's more to say on the Diet Coke and Mentos story? There is.
After the last go-round, I sent off a note to Richard Zare at Stanford University. Besides being a world-renowned chemist, Zare has a particular fascination with bubbles. He recently showed why the bubbles actually go down the side of the glass when you first pull a pint of Guinness.
So I wrote to him and asked his take on why dropping Mentos in a bottle of Diet Coke caused the bubbly liquid to shoot out. He wrote back from China to say he was sure anything with a rough edge dropped into bubbly soda would cause the geyser, including sand or salt. He recently sent this picture and caption to prove his point.