Wednesday, July 3, 2013

Mentos and Diet Coke

Fountains overflowing.
Our Science-Nature Club met in June to have some messy science fun--Mentos and Diet Coke fountains. We separated into five teams. Each team had one room-temperature Diet Coke and an additional different soda to compare to the Diet Coke. Here are the types of soda they compared:

Diet Coke vs regular Coke
Diet Coke vs Sprite Zero
Diet Coke vs store-brand diet cola
Room-temperature Diet Coke vs cold Diet Coke
2-liter Diet Coke vs 1-liter Diet Coke

They placed two Mentos into each bottle at the same time and recorded which fountain went higher and which one had more soda left in the bottle after the fountain.

After we cleaned up our mess, we came back together and each team reported its findings. We then began to discuss what was happening. Nucleation was the new word of the day (the bubbling process). We learned that the two things that make Mentos so special are: (1) it is covered with lots and lots of tiny pits on the surface (like a golf ball) and (2) the fact that they sink to the bottom of the soda. Carbon dioxide bubbles form on the Mentos and then quickly rise to the surface. The gas released by the Mentos pushes the liquid up and out in a fantastic soda blast.  We determined that room-temperature Diet Coke worked the best.

At the end of our meeting, everyone was given their own bottle of 20 oz. Diet Coke and two Mentos. We counted to three and . . . BLAST OFF!

--by Evie M.