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Mentos and Soda Project

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Mentos and Soda Project - The Aftermath
This is the 'after' photo of the mentos & diet cola fountain.

This is the 'after' photo of the mentos & diet cola fountain. Notice how everyone scattered except Ry, now totally soaked?

Anne Helmenstine
Yes, you could clean up, but since you are wet, you may as well do the project again and again and again. Would you like to know what happened to cause the soda to spray? Before you open the soda, the carbon dioxide that makes it fizz is dissolved in the liquid. When you open the bottle, you release the pressure of bottling and some of that carbon dioxide comes out of solution, making your soda bubbly. The bubbles are free to rise, expand, and escape.

When you drop the Mentos candies into the bottle, a few different things happen at once. First, the candies are displacing the soda. The carbon dioxide gas naturally wants up and out, which is where it goes, taking some liquid along for the ride. The soda starts to dissolve the candies, putting gum arabic and gelatin into solution. These chemicals can lower the surface tension of the soda, making it easier for bubbles to expand and escape. Also, the surface of the candy becomes pitted, providing sites for bubbles to attach and grow. The reaction is similar to what happens when you add a scoop of ice cream to soda, except much more sudden and spectacular (and less tasty).

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