Exploration and Discovery
Our youngest is building a rocket ship so he can explore the solar system. He is investigating ways to power it by testing out different ideas for propulsion. Watching movies like Interstellar and Apollo 13 have inspired him to dream big, so we are encouraging his experimentation and research.
The Mentos Diet Coke experiment was at the top of his list to see what happens when a reaction occurs between two substances. We think the verdict is out among science gurus as to whether or not a chemical reaction occurs in this case. The popular consensus is that a physical, not chemical, reaction happens because of a combination of carbon dioxide in the Diet Coke and the structure of the Mentos, which causes nucleation to occur. So, we tried it out for ourselves using a large bottle (about 1 liter) of Diet Coke with a full roll of Mentos. (Check out our results in the video below.)
We wedged the bottle between some rocks to keep it from tipping over, and we made a simple funnel with a piece of paper. One brother held the funnel while the other one poured in the Mentos. We thought it would work best to add all the Mentos as quickly as possible and then get out of the way.
While the reaction was less than spectacular, we did learn a lot from the experiment, and it led to further questions about the variables that affect the results. Now, the boys want to try it again under different temperature conditions, using a different sized Diet Coke bottle, using different flavored Mentos, and using different brands of soda. So, scientific inquiry is definitely at work, and that is the true goal of this activity.