Diet Coke and Mentos: An Experimental Study
UPDATE: The UCI chemistry outreach program has a detailed set of instructions on how to do this and other do-it-yourself chemistry experiments. That page also has links to other outreach programs, some of which have more demonstrations that you can do. Have fun!
Abstract
From videos collected on the internet, it seems likely that Diet Coke and Mentos mints, when mixed, will produce a violent reaction. Based on the assumed mechanism of the reaction, we theorized that other sodas and mint products might exhibit the same behavior when combined. Tests were performed, and in the end Mentos mints gave the most spectacular result, independent of the brand of soda used. Effect of soda container size was also investigated.
Introduction
Ever since man first stepped out of the African plains, he has been fascinated by the act of blowing shit up. Explosions, violent reactions, and rapid depressurizations have been a staple of entertainment for years, and continue to be so to this day. From a practical standpoint, explosions which involve fire and/or blast waves, while exciting, are dangerous and do not lend themselves to being performed on a college campus. For this reason, explosive reactions which can be created with household objects and which form no dangerous products are to be valued.
The internet is a valuable source of such reactions, especially since the advent of Google Video. Any idiot with a camera and a cool explosion can put a video on the internet for the whole world to see; this has resulted in videos of thermite reactions and dry ice bombs and, intriguingly, a rather explosive Diet Coke fountain.
The experiments described here were performed in an attempt to characterize this fountain and to get us the hell out of our lab, because the construction is getting really annoying.
Materials and Methods
Several containers of soda were purchased at a local Albertson's supermarket, based on what was on sale that morning. Brands purchased included Diet Coke (12 cans and three two-liter bottles) and Sierra Mist Free (three two-liter bottles). Mint products purchased included three boxes of Mentos mints, two tins of Altoids mints, and four packs of Dentyne Ice peppermint gum.
Figure 1. The materials for the experiment.
Mints were introduced to the soda container by means of a cardboard tube; a flat piece of cardboard was placed between the tube and the bottle to hold the mints in place, and removed to allow the mints to fall into the soda container. For all trials, at least ten mints were dropped into the soda at once. The reaction was observed to occur slowly and incompletely when a single mint was used.
The experiments were conducted in the middle of Aldrich Park on the campus of the University of California, Irvine (undergrad students and other passers-by seemed amused), so that we wouldn't have to clean up the soda that sprayed everywhere. All other trash was disposed of properly, so relax, tree-huggers!
Results and Discussion
It was determined that the only type of mint that produced the expected result was the Mentos; the gum and Altoids gave off some bubbles but nowhere near the earlier observed geyser of cola. All further results are for Mentos mints, since they were the coolest.
The can of Diet Coke was also somewhat of a disappointment. Although a small soda geyser was observed:
Figure 2. Mentos and a Diet Coke can. Zoom in to see the small Diet Coke geyser
but nothing impressive happened. Next, the Mentos were added to the diet Sierra Mist bottle, to see if the reaction that happened in Diet Coke would also happen with a clear soda. This reaction was very fast, and in fact surprised one of our testers:
Figure 3. Unfortunate tester is surprised by the quickness with which the Sierra Mist/Mentos system begins to react. From this point forward, more care was taken.
When this reaction was tried again, the reaction was spectacular:
Figure 4. Reaction of Mentos with Sierra Mist Free.
Finally, the Diet Coke and Mentos were combined, to gauge the various magnitudes of the reaction in different sodas. Both sodas in the 2-liter bottles gave about the same result:
Figure 5. Reaction of Mentos with Diet Coke.
The reaction of Mentos with Diet Coke is not, as some have surmised, a chemical reaction, and no products other than flat Diet Coke, soggy Mentos and carbon dioxide are produced. The reason that the soda erupts so violently from the bottle is actually twofold: a decrease of the surface tension of the soda (due to dissolving Mentos), and an increase in nucleation sites (sites where bubbles of CO2 can form) within the bottle (due to the rough Mentos surface). Both of these factors make the carbon dioxide in the soda less likely to stay dissolved and more likely to become gaseous. The fountain effect is from all of the CO2 going from dissolved to gaseous at once, and at a great rate.
Another interesting phenomena was observed, one that would seem to confirm centuries of observation:
Figure 6. Female lab members observing the proceedings, but seemingly not impressed in the least.
Not surprisingly, the female members of the lab were not as interested in the spraying soda and flying mints as were the male lab members. This would seem to confirm the observation that men are just more easily amused as a group than are women.
Conclusion
You should definitely try this at home.
Tags: diet coke and mentos, at-home chemistry, explosions, fun with science
Abstract
From videos collected on the internet, it seems likely that Diet Coke and Mentos mints, when mixed, will produce a violent reaction. Based on the assumed mechanism of the reaction, we theorized that other sodas and mint products might exhibit the same behavior when combined. Tests were performed, and in the end Mentos mints gave the most spectacular result, independent of the brand of soda used. Effect of soda container size was also investigated.
Introduction
Ever since man first stepped out of the African plains, he has been fascinated by the act of blowing shit up. Explosions, violent reactions, and rapid depressurizations have been a staple of entertainment for years, and continue to be so to this day. From a practical standpoint, explosions which involve fire and/or blast waves, while exciting, are dangerous and do not lend themselves to being performed on a college campus. For this reason, explosive reactions which can be created with household objects and which form no dangerous products are to be valued.
The internet is a valuable source of such reactions, especially since the advent of Google Video. Any idiot with a camera and a cool explosion can put a video on the internet for the whole world to see; this has resulted in videos of thermite reactions and dry ice bombs and, intriguingly, a rather explosive Diet Coke fountain.
The experiments described here were performed in an attempt to characterize this fountain and to get us the hell out of our lab, because the construction is getting really annoying.
Materials and Methods
Several containers of soda were purchased at a local Albertson's supermarket, based on what was on sale that morning. Brands purchased included Diet Coke (12 cans and three two-liter bottles) and Sierra Mist Free (three two-liter bottles). Mint products purchased included three boxes of Mentos mints, two tins of Altoids mints, and four packs of Dentyne Ice peppermint gum.
Figure 1. The materials for the experiment.
Mints were introduced to the soda container by means of a cardboard tube; a flat piece of cardboard was placed between the tube and the bottle to hold the mints in place, and removed to allow the mints to fall into the soda container. For all trials, at least ten mints were dropped into the soda at once. The reaction was observed to occur slowly and incompletely when a single mint was used.
The experiments were conducted in the middle of Aldrich Park on the campus of the University of California, Irvine (undergrad students and other passers-by seemed amused), so that we wouldn't have to clean up the soda that sprayed everywhere. All other trash was disposed of properly, so relax, tree-huggers!
Results and Discussion
It was determined that the only type of mint that produced the expected result was the Mentos; the gum and Altoids gave off some bubbles but nowhere near the earlier observed geyser of cola. All further results are for Mentos mints, since they were the coolest.
The can of Diet Coke was also somewhat of a disappointment. Although a small soda geyser was observed:
Figure 2. Mentos and a Diet Coke can. Zoom in to see the small Diet Coke geyser
but nothing impressive happened. Next, the Mentos were added to the diet Sierra Mist bottle, to see if the reaction that happened in Diet Coke would also happen with a clear soda. This reaction was very fast, and in fact surprised one of our testers:
Figure 3. Unfortunate tester is surprised by the quickness with which the Sierra Mist/Mentos system begins to react. From this point forward, more care was taken.
When this reaction was tried again, the reaction was spectacular:
Figure 4. Reaction of Mentos with Sierra Mist Free.
Finally, the Diet Coke and Mentos were combined, to gauge the various magnitudes of the reaction in different sodas. Both sodas in the 2-liter bottles gave about the same result:
Figure 5. Reaction of Mentos with Diet Coke.
The reaction of Mentos with Diet Coke is not, as some have surmised, a chemical reaction, and no products other than flat Diet Coke, soggy Mentos and carbon dioxide are produced. The reason that the soda erupts so violently from the bottle is actually twofold: a decrease of the surface tension of the soda (due to dissolving Mentos), and an increase in nucleation sites (sites where bubbles of CO2 can form) within the bottle (due to the rough Mentos surface). Both of these factors make the carbon dioxide in the soda less likely to stay dissolved and more likely to become gaseous. The fountain effect is from all of the CO2 going from dissolved to gaseous at once, and at a great rate.
Another interesting phenomena was observed, one that would seem to confirm centuries of observation:
Figure 6. Female lab members observing the proceedings, but seemingly not impressed in the least.
Not surprisingly, the female members of the lab were not as interested in the spraying soda and flying mints as were the male lab members. This would seem to confirm the observation that men are just more easily amused as a group than are women.
Conclusion
You should definitely try this at home.
Tags: diet coke and mentos, at-home chemistry, explosions, fun with science
posted by The Disgruntled Chemist at
6:58 PM
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