DLC Blog

Mentos + Coke = ???

Have you ever heard of an urban legend that you will die if you eat pop rocks and drink soda at same time? Well, this is not true. Pop rocks and soda won’t kill you. Meanwhile, if you eat mentos and drink soda at same time, that might actually hurt you (so don't do it!!!). Well, please watch this video.

Mentos contains gum arabic, which lowers the surface tension of water and therefore causes increased fizzing in carbonated beverages. One thing that casts doubt on the gum arabic theory, however, is that several items that contain no gum arabic whatsoever also cause soda to foam violently. Several chemists have since stepped forward to say that while gum arabic may contribute to the reaction, that can’t be the only cause.

These chemists are saying that the primary cause is physical, not chemical. Their explanation: nucleation sites. If you have a liquid that is supersaturated with gas (like soda, which is pumped full of carbon dioxide), a nucleation site is a place where the gas is able to form bubbles. Nucleation sites can be scratches on a surface or specks of dust – anywhere that you have a high surface area in a very small volume. That's where bubbles can form. Mentos seem to be loaded with nucleation sites. In other words, there are so many microscopic nooks and crannies on the surface of a Mentos gum that an incredible number of bubbles will form when you drop it in a bottle of soda. Since the Mentos are also heavy enough to sink, they react with the soda all the way to the bottom. The escaping bubbles quickly turn into a raging foam, and the pressure builds dramatically.

Miyagi
PS - DON'T do this inside of the house, your parents will be sooooo mad. Take it outside and take necessary safety precautions like goggles and a clear escape route.

Posted by Hayato at October 24, 2006 03:52 PM in Science.