Andrew Bonner Period 8 September 29, 2009 Diet Coke and Mentos Eruption
In the Mentos-Diet Coke reaction there are several different variables that can be modified in order to change the results of the reaction as with any other experiment. The temperature of the soda and the temperature of the Mentos and the can be a major deciding factor to the height of this reaction. The source of this reaction is believed to be caused by the small pores in the Mentos outer covering acting as nucleation sites for the tiny carbon dioxide bubbles to form on the surface of the Mentos. These bubbles eventually break away from the Mentos surface and float to the surface of the soda and there form an explosive reaction of foam due to the large volume of foam in the relative small amount of space it has to expand in inside the bottle. Surprisingly, this is actually a physical reaction since the sodas physical form is the only thing that ever changes1. The question is, does the temperature of either the candy or the soda or both affect the height of the reaction. When the temperature of the Mentos is raised or lowered the height of the reaction is clearly changed in relation. As tested by Cutler and Smith the coldest Mentos proved to create the highest reaction at a rough estimate of 350 cm when ten Mentos were cooled to a temperature of 263 K. Surprisingly the next highest reaction was the one caused by the heated Mentos. When ten Mentos were heated to 313 K the reaction reached a height of 200 cm. The lowest reaction was caused by Mentos left at room temperature (303 K) which caused a reaction height of 30 cm 2. These results show that the height of the reaction is directly affected by the temperature of the candies added to the soda. These results also bring the questions of will changing the temperature of the Mentos more drastically make the height of the reaction? If the
Mentos that were cooled were only cooled 10 K similarly to the heated Mentos only being heated 10 K, would the difference in the height between the heated and cooled reactions change? Furthermore, Why did the Mentos that had there temperature change react so violently when compared to the reaction from the Mentos left at room temperature? Does it have something to do with the fact that the Mentos temperature was changed not the way they were changed (heating or cooling)? It would be plausible to conclude from this data that the eruption height has a direct relation to the difference in temperature of the Mentos common temperature and changed temperature. It seems as though changing the temperature was the only reason that the reaction was effected, not the way the temperature was changed. In addition, the temperature of the soda also had an effect on the height and length of the Diet Coke-Mentos reaction3. As tested and proven by Husted, the height and length of the reaction is clearly dependent on the temperature of the soda. When Diet Coke was cooled to a temperature of 262 K, heated to a temperature of 308 K, and left a temperature of 298 K the reaction was clearly was affected. The soda that was cooled produced a reaction height of 20 cm. The soda left a room temperature surpassed that by five times with a reaction height of 100 cm which was outdone by the heated soda which produced a reaction height of 300 cm4. This drastic change in reaction height is probably due to the fact that all of the carbon dioxide in the Diet Coke expanded in the heated soda and contracted in the cooled soda. Since the carbon dioxide had a much greater volume in the heated soda when compared to the cooler sodas, the volume of the foam was much greater causing a higher reaction. Furthermore, the carbon dioxide wasn't the only ingredient in the Diet Coke to expand; as common with most substances, as temperature increases so does the volume of the substance. This would have caused the eruption to further exceed the capacity of the soda bottle.
As you can see, there is a direct relationship between the temperature of the ingredients and the height of the reaction. Oddly, the effects of the temperature change arenâ€™t similar between that of the Mentos and that of the soda. As the Mentos were heated or cooled the height of the reaction would increase while the height of the reaction was only increased when the soda was heated. This starts the idea that the volume increase and decrease of the Mentos has very little to do with the height of the reaction, since height increased even when the Mentos were cooled and contracted. The pores in the surface of the Mentos, which act nucleation sites in this case, are more or less affected by the changes from there natural temperature. For whatever reasons, the nucleation sites are more able to produce bubbles and create more violent reactions. On the other hand, the increase in reaction height may not have anything to do with the nucleation sites at all; this difference may be the product of some other substance in the surface of a Mentos that was affected by the change in heat making it more apt to have violent eruptions. Overall, the height of the Diet Coke-Mentos eruption is dependent upon the temperature of the reactants.
1. American Journal of Physics, Volume 76 number 6 Tonya Coffey 2008 2. Guilford Journal of Chemistry, Volume 1, Cutler and Smith 3. www.stevespanglerscience.com, Mentos and soda temperature. 4. Guilford Journal of Chemistry, Volume 1, Husted 5. Guilford Journal of Chemistry, Volume 2, Melillo and Guryinov
Sahil V. Makhijani Tuesday, September 29, 2009 Period 8 Brielmann Hon. Chem.
Mentos Review Paper The Effect of Flavor on Eruption Height Ever since it was first discovered, the diet coke-and-mentos eruption has been recreated several times on TV shows and viral videos, most famously by Fritz Grobe and Stephen Voltz, who call themselves the Eepybirdsi. The Eepybirds have made guest appearances on several TV shows, set records for their absurd eruption videos, and continue to tour to this day. However, they claim to use conventional Diet Coke and mint Mentos for their eruptions. There is a numerous variety of Mento flavors, other than mint, including mixed fruit, cinnamon, grapefruit, plum, raisin, yoghurt, currant, and even fresh colaii. The Eepybirds, along with The Mythbustersiii, claim that the combination of mint Mentos with Diet Coke creates the greatest eruption. Jamie Hyneman of the Mybusters duo states that the fruity flavors have a smooth, waxy coating compared the mint kind. This smoother coating results in bad nucleation sites for a smaller eruption. However, other studies indicate that the more fruity flavors will cause a bigger reaction than the standard mint flavor. One example comes from a paper written by Tonya Shea Coffeyiv, definitively states that fruit mentos resulted in a larger displacement of soda mass in the bottle, as well as a longer spray distance than regular mint mentos (and diet coke). Her experiments claim that fruit mentos displaced 30g more diet soda than mint, while the spray from the fruit mento reaction flew 1.5ft farther than the spray from the mint mentos. Another investigation, conducted by fellow high school students Allison Federici and Jess LaChancev, compared five different mento flavors: mint, fruit, sugar-free, sour, and 5
cinnamon. Two trials were conducted with each flavor (and diet coke) for the height of the spray. Their results conclude that the cinnamon mentos resulted in a spray 1.5cm higher when reacted with the diet coke compared to the regular mint. In comparison to Coffey’s investigation, the mint mento and fruit mento eruption heights were practically identical in both of their trials. Nevertheless, this data also confirms that mint mentos are not the best kind for diet coke eruptions. As further investigations on the ideal mento flavor for a better eruption continue to contradict each other, we begin to wonder about the truth behind the sweet phenomenon. Since this topic is considered irrelevant to the field of research and investigation, we may never really find out enough about the chemical process and the key ingredients that are responsible. However, we have uncovered some plausible explanations for the reaction: the concept of nucleation on the surface of the mentos explains for the sudden rush of CO2, diet soda works better than regular soda and carbonated water, and mint mentos may not be the best type of mentos for a bigger eruption. Hopefully, we will one day discover the ideal combination of soda and candy for the biggest and best eruption.
Eepybird’s website: http://www.eepybird.com/ Wikipedia, “Mentos- Flavors”: http://en.wikipedia.org/wiki/Mentos#Flavors iii Overview on the Mythbusters episode on diet coke + mentos (quote by Hyneman): http://www.zap2it.com/tv/news/zap-mythbustersmentos,0,4325641.story iv American Journal of Physics (article by Coffey): http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000076000006000551000001&idtyp e=cvips&gifs=yes v Guilford Journal of Chemistry, Vol. 2 pgs. 15-16: http://chemistryadventure.com/Documents/guilford%20journal%20of%20chemistry%20volume%202.pdf ii
Rebecca Mahoney September 29, 2009 Period 8
The Effect of Temperature on the Height of Mentos and Diet Coke Eruptions As some previous studies have shown, the temperature of diet coke in a mentos eruption does have an effect on the height of it. The hotter the beverage is, the higher the eruption will be. In one experiment, cold (262 K), room temperature (298 K), and warm diet coke (308 K), was used to differentiate their affects on the height of a mentos eruption.1 Besides the temperature, everything else was the same about each trial. Each bottle had eight mentos put into it when conducting the experiment. After the testing took place, the expected results were found.2 The bottle with warmest diet coke had the highest eruption, the room temperature diet coke had the second highest eruption, and the coldest diet coke had the lowest eruption. 3 In another experiment, the same types of results were found. The temperatures used for the experiment were 320 K, 311 K, and 284 K.4 1
This experiment was tested by Justin Husted and was in the Guilford Journal of Chemistry under the title of â€œWarm Soda has a Dramatic Effect on the Height of a Mentos Eruption.â€? The soda got to the certain temperatures by putting the bottles in water of the desired temperature. The middle temperature of soda was kept in the classroom for two days, instead of being put in water. 2
The expected results were that warmer soda has a greater reaction
The highest reaction was 300 centimeters, the second highest was 100 centimeters, and the lowest reaction was about 20 centimeters high.
In another experiment, the same types of results were found. The temperatures used for the experiment were 320 K, 311 K, and 284 K.4 Also, the results were not showing the differences in heights of the eruptions, but the amount of mass (g) lost. 5 It did not say how many mentos were put in each diet coke bottle either, but used 30 grams of mentos in each. It did say they were mint mentos, though, which is the same type used in the other experiment by Justin Husted. The hotter the beverage, though, the more explosive reaction was concluded. It said that the temperatures affect on the mentos eruptions was due to Le Chatelierâ€™s principle: P=Kc.6 In the experiment, the stress applied increases the temperature of the diet coke. This moves the system away from equilibrium condition for the molar concentration of gas. This means when the mentos are dropped into the liquid, the system moves toward equilibrium which is the explosive reaction.7 From the work of Tonya Shea Coffey and Justin Husted, it can be seen that hotter beverages create larger mentos and diet coke eruptions. Even though there is a very limited amount of studies, research, and experiments on the general topic as a whole, it seems as though these results contain valid answers. This concludes that, the warmer the diet coke is, the larger the explosion of the mentos and diet coke will be. 4
This information was found in â€œDiet Coke and Mentos: What is really behind this physical reaction?â€? by Tonya Shea Coffey. These temperatures were originally in degrees Celsius, but were converted into Kelvin. 5 The highest temperature had an amount loss of 1450 grams, the middle temperature had a mass loss of 1350 grams, and the lowest temperature had a mass loss of 1280 grams. 6 P is the partial pressure of the gas above the liquid, K is a parameter, and c is the molar concentration of the gas. 7 The system moves toward equilibrium by liberating the excess carbon dioxide from the solution. 8
Caleb Fridell Sept. 29, 2009 Period 8
Mentos Review Article: Effect of Nucleation Sites on Mentos
The many pits covering the surface of Mentos candy popularly known as nucleation sites are credited by many as the source for the fantastic eruptions when the candy is dropped into soda. Mentos candy has a very rough surface, with thousands of microscopic nucleation sites. The theory is that these nucleation sites provide areas for the Carbon Dioxide bubbles to form, and rush to the surface of the soda. When the Mythbusters tested this theory1, they used one normal Mint Mento, and a Fruit Mento, which was layered with a wax sealer that Jamie claimed inhibited the nucleation process. Their first test used the Mint Mento, which was covered with nucleation sites, as a control. As predicted, the soda erupted when the Mento was dropped in. However, when the smooth surfaced Fruit Mento was dropped in, there was absolutely no eruption. The Mythbusters concluded that the cause of the eruption was the rough surface, which contained several nucleation sites. For videos of the experiments and further explanation, see the Mythbusters episode1. In her report, â€œDiet Coke and Mentos: What is really behind this physical reaction?â€?2 Professor Coffey identified the roughness of the Mento as a major factor for the eruption. Coffey proved this by taking SEM images of the Mentos and other tested substances to measure the roughness of the surface. The Mentos, which had a rms roughness of 442, had a much higher root-mean-square roughness than other test subjects such as Rock salt, which had a rms 9
roughness of only 174. The eruption results showed a positive correlation with the roughness. The Mentos tested had a more explosive eruption, and the soda lost much more mass with the Mentos than rock salt. However, the Wint-o-Green Lifesavers showed a much higher rms roughness with an astounding 2630 but failed to create eruptions that were more explosive or cause a larger loss in soda. From this information, Coffey concluded that although the roughness of the surface created more nucleation sites and thus created better eruptions, they were not the sole factor, as Wint-o-Greens were rougher but had worse eruptions. Lee Marek, who was the first major performer of the Mentos and Diet Coke experiment appeared on the 1999 David Letterman Late Show said that the reaction was due to nucleation sites3. Marek said that dropping anything into the carbonated Diet Coke would produce the bubbles but since Mentos had so much surface area and places where the Carbon Dioxide could nucleate, its reaction was biggest. Marek said that the reaction was solely because that the Mento broke the surface tension, and provided nucleation sites, and then sunk to the bottom to push the soda out of the bottle3. All three of the scientific studies that were reviewed agreed that the nucleation sites were a major factor in the eruption because the bubbles were formed in the pits, and the Mento sunk to the bottom to push the soda out of the bottle. However, Marek gave this as the only reason, and did not conduct sufficient studies to prove his theory. Having seen that the Mentos caused an eruption, and that they had several nucleation sites, he listed this as the only reason without providing a substance with as many nucleation sites to compare as Coffey did (Wint-o-Green Lifesavers). His theory was shown to be correct by the Mythbusters and Coffey, but his experiments alone were not sufficient proof. The Mythbusters tested the nucleation sites well, proving that they were one of the causes of the eruption, and also cited the other reasons. 10
Coffey’s report went into the greatest detail of the three, giving ample explanation with all of the necessary proof to give support. In conclusion, the Mentos played a major factor in the eruption, but were not the sole cause.
Mythbusters “Episode 57: Mentos and Diet Coke”, Discovery Channel
“Diet Coke and Mentos: What is really behind the physical reaction?” Tonya Shea Coffey,
American Journal of Physics, Volume 76, Number 6, June 2008 3
Lee Marek on David Letterman Late Show 1999, Lee Marek Website
Amanda Simon September 29, 2009 Honors Chemistry Period 8
The Effect of Soda Temperature on the Soda Mentos Eruption Review Article Introduction Various experiments have been conducted concerning the soda Mentos eruption to discover what specific factors influence the reaction to produce the largest eruption. Some of these factors include the type of Mentos, importance of nucleation sites, Mentos temperature, soda eruptions without Mentos, and varying nozzle effects. An additional factor that is significant in the reaction is the temperature of the soda. Not many experimenters have dared to test this factor but it plays an important role, actually producing a much larger eruption when the soda is warmer. A few studies have been conducted to support this claim. Experiments One study conducted by Justin Husted in 2007 specifically proved that for every ten degrees Celsius that Diet Coke is heated, the reaction rate appears to double and similarly, for every ten degrees Celsius that Diet Coke is cooled or frozen, the reaction rate decreases by half.1 The temperature of the soda also affects the height and power of the reaction in that the warmer the temperature, the greater the reaction force and height.2 The experiment consisted of placing three bottles of diet coke into different water temperatures which were cold (262 K), room temperature (298 K), and warm (approximately 308 K). A controlled number of 8 Mentos were placed in each bottle to discover the effect of the soda temperature of the reaction. In Hustedâ€™s experiment, the eruption in the warm soda produced an explosion 300 cm high while the cold
soda explosion was only 20 cm high.3 Clearly, the results were clear and accurate, proving warmer beverages produce greater eruptions while the cold soda produced the smallest reaction. Another study conducted by Professor Tonya Shea Coffey of Appalachian State University involved the investigation of the effect of soda temperature on the eruption height of the soda Mentos reaction. Using contact angles, an AFM, and an SEM as tools in the numerous experiments, Coffey was able to arrive at several conclusions as to what conditions yield the largest, most effective eruptions. Related to the effect of soda temperature on the explosion, Coffey and her team used Henry’s law which applies to gases dissolved in liquids to show that a beverage with a higher temperature will produce a more explosive reaction. 4 When the parameter K increases with the temperature increase of the soda, the molecular concentration of the gas drops to create the same value of partial pressure as before.5 The drop in concentration means that the gas becomes less soluble in liquids with the temperature continuing to increase.6 Le Chatelier’s principle applies because it states ‘If, to a system at equilibrium, a stress be applied, then system will react so as to relieve the stress.’7 The temperature increase causes the system (soda) to move away from equilibrium but when the mento is dropped into it, the system begins to move back toward equilibrium by freeing the excess carbon dioxide from the solution by exploding.8 Coffey’s work obviously supports the fact that the hotter the beverage, the more explosive a reaction will be. Conclusion There are numerous factors which affect the height and force of the widely spread Mentos exploding in soda reaction. A majority of the causes have been discovered through various experiments performed unofficially by everyday people, students in classrooms, or by Professor Coffey. The different experiments have proved continually that the temperature of the 13
soda severely affects the height and force of the eruption. The hotter the beverage is, the larger the explosion. This is supported by Husted’s experiment where the hot beverage caused an eruption 15 times higher than the eruption created by the cold beverage. Additionally, Coffey’s experiment displayed that a soda of increased temperature produces a higher eruption by using Henry’s law and Le Chatelier’s principle to explain the reason why this is true. All of the relevant research consistently show that the hotter a soda is, the larger an explosion it creates.
Justin Husted, Guilford Journal of Chemistry, Volume 1, Page 19 (2007). Justin Husted, Guilford Journal of Chemistry, Volume 1, Page 19 (2007). 3 Justin Husted, Guilford Journal of Chemistry, Volume 1, Page 19 (2007). 4 Tonya Shea Coffey, Diet Coke and Mentos: What is really behind this physical reaction? Page 556 (Accepted in 2008) 5 Tonya Shea Coffey, Diet Coke and Mentos: What is really behind this physical reaction? Page 556 (Accepted in 2008) 6 Tonya Shea Coffey, Diet Coke and Mentos: What is really behind this physical reaction? Page 556 (Accepted in 2008) 7 Tonya Shea Coffey, Diet Coke and Mentos: What is really behind this physical reaction? Page 556 (Accepted in 2008) 8 Tonya Shea Coffey, Diet Coke and Mentos: What is really behind this physical reaction? Page 556 (Accepted in 2008) 2
Micaela DeMasi-Sumner Period 8 September 26 2009
Diet Coke and Mentos Eruptions Diet Coke and Mentos explode when they come in contact. The typical experiment used to prove this is done by dropping Mentos in a bottle of Diet Coke and running away. The eruption can vary from a few inches to several feet in height depending on what alterations where made to the typical experiment. In order to observe the full effect of the eruption, Mentos should be tied to a string and dropped in the Diet Coke bottle, this allows the experimenters to be sure the Mentos will not miss the bottle when being dropped. There is no limit to the possible types of eruptions Diet Coke and Mentos could make together. Both ingredients have been around for decades, so many of the possible forms of explosions have been tried. Explosions have been tried on television as well as in classrooms and houses, but they can all be shared over the internet in places such as YouTube, and Google Videos. On YouTube videos have been submitted as long ago as 3 years. This is a considerably long time ago because YouTube is still fairly young.1 By searching “diet coke and mentos” on YouTube, thousands of videos will come up as results. The eruptions are mostly not scientifically sound and do not support scientific ideas; they are mostly just done for entertainment. However, the MythBuster’s result and the Letterman Show’s demonstration are also a part of YouTube and can be viewed. “The Diet Coke and Mentos reaction was the subject of a 2006 MythBusters episode and first shown in 1999 on the David Letterman show.”2 This experiment was 15
historically done to pass time in a fun manner and is still used that way today. By being shared in public, a larger population then in past times became aware of the reaction. Although there is not one sure ingredient or ‘thing’ that is solely responsible for the reaction the MythBusters were able to target one cause. As is shown on the MythBuster’s show, and is available on YouTube, the Diet Coke and Mentos reaction is demonstrated by the professionals on the show. They found out that nucleation was a large contributing factor in the explosion. They explained this by describing the process like the following; pitted increased surface area allows CO2 to bubble and attach to Mentos and then release causing the bottle of Coke to erupt.3 The MythBusters also stated that the fruit Mentos were smooth and ‘waxy’ so they did not cause an impressive eruption, but in eruptions done by Tonya Shea Coffey prove that fruit Mentos actually do erupt on a large scale. Fruit Mentos were dropped into Diet Coke in Coffey’s eruption and the spray was 17.8 ft at it greatest height.2 These experiments were not even the first to be done ever, but they were documented so the general public could easily find out when they occurred. The exact date of the first ever Diet Coke and Mentos eruption is unclear, but, the dates Coca Cola was invented and Mentos were invented are easily looked up. Coca Cola was invented in 1886 by Doctor John Pemberton.4 However, Mentos came many years later. Michael van Melle and Pierre van Melle invented Mentos in 1932.5 So the original reaction could not have taken place before the invention of both ingredients, so the reaction came no earlier than 1932.
In conclusion, Mentos and Diet Coke eruptions take place when the two ingredients touch. These explosive reactions can be seen on YouTube as well as on re-runs of MythBusters. These experiments have been done for at least a decade but possibly longer. Nucleation is one explanation for the reaction of Diet Coke and Mentos, but there is not much scientific information to back other theories. This is a simplistic experiment that demonstrates possible happenings between two seemingly random substances. Overall, the results will vary, but Diet Coke and Mentos will explode when mixed together because they have a history of doing so.
1. 2. 3. 4. 5.
YouTube. This site contains many results on Diet Coke and Mentos eruptions. Tonya Shea Coffey. Diet Coke and Mentos: What is really behind the reaction? This article was published in the American Journal of Physics. MythBusters- Diet Coke and Mentos: Season 5, Episode 12. The results of this episode are available on YouTube. http://www.solarnavigator.net/sponsorship/coca_cola.htm This site explains who invented Coca Cola, and when it was invented. http://www.mentos.com/?tld=us#/FAQ This is a site dedicated to Mentos information and publicity.
Ted Jensen Period 8 Nucleation Sites and the Diet Coke-Mentos Reaction The explosive combination of Mentos mints and Coke has been the target of scientists, entertainers, and students alike. When combined, the soda is released as a jet of Coke through the top of the bottle. Studied by Mythbusters and other formal studies such as that of Tonya Coffey, the cause of this reaction has not been formally identified, but one of the identified main causes is the nucleation sites. Nucleation is the process by which bubbles form on surfaces. In a soda factory, carbon dioxide gas is pumped into the soda with a lot of pressure. The result is the carbonation of the soda, or “fizziness,” where the gas stays suspended in the bottle until it is able to escape or form bubbles 1. But why do these bubbles form? An article on the Royal Society of Chemistry gives a good explanation. Because gas is more soluble at higher pressures, a large amount of carbon dioxide is able to be forced into a pressurized bottle of soda 2. When the bottle, is opened, the pressure is reduced and the “liquid is momentarily supersaturated with gas.” The gas begins to escape and does so through bubble formation. When bubbles do form, they form on the sides of the bottle or on another object within the bottle. This stays with the theory that bubbles form on surfaces 2. Michael L. Corradinni, a professor at the University of Wisconsin School of Engineering describes the formation of “vapor from a liquid” when he states, “Vapor may form from a liquid (a) at a vapor-liquid interface away from surfaces, (b) in the bulk of the liquid due to density fluctuations, or (c) at a solid surface with pre-existing vapor or gas pockets. In each situation one can observe the departure from a stable or a metastable state of equilibrium” 3. The idea that vapor
forms at a “solid surface with… gas pockets” shows exactly what is happening to the mentos. Though
Mentos look smooth and even feel it sometimes, they are not. According to the Mythbusters’ Adam Savage in an episode about the Mentos-Cola explosion, the “surface of the [mentos] is covered with microscopic pits and lots of more surface area than you can actually see” 4. The rough surface of the Mentos provides these “gas pockets” and nucleation sites for carbon dioxide bubbles to form. According to Professor Tonya Coffey, in her article Diet Coke and Mentos, a regular Mint Mentos has a “Root-mean-square roughness” of 442 nanometers, as opposed to a Wint-ogreen Lifesaver at 2,630 nm, and rock salt at 174 5. With this measure, it can be determined that a Wint-o-green lifesaver is the most rough, followed by the Mint Mentos and finally, the rock salt. Because the Mentos candies have a surfactant present that sets them apart from others tested, it is more important to look at the differences between more similar variables: the Lifesaver and rock salt. Coffey states that the Lifesavers have and rms roughness of “more than a factor of 10” larger than that of rock salt. The Lifesavers, when placed in Diet Coke, caused a total mass lost of 1430 g and a spray distance of 7.0 ft. The rock salt, also placed in Diet Coke, caused a total mass of 1170 g lost and spray distance of 6.3 ft. Clearly, the Wint-o-green lifesaver, the candy with the greatest roughness, caused a more massive and powerful explosion of Diet Coke. An increase in the number of nucleation sites will allow more carbon dioxide bubbles to form and escape. Though nucleation sites are not the sole cause of the Diet Coke- Mentos reaction, they are a large contributor to its explosive result. For the absence of nucleation sites on a Mentos candy would not allow the formation of carbon dioxide bubbles, and therefore cause no or a very small eruption. 19
Endnotes 1. Steven Spangler has done numerous experiments and demonstrations with the CokeMentos phenomenon. His article on the explosion can be found here: http://www.stevespanglerscience.com/experiment/00000109
2. The RSC, or Royal Society of Chemistry, is a European organization of scientists that publish articles on their website about specific topics. The Diet Coke-Mentos Explosion article can be found here: http://www.rsc.org/education/teachers/learnnet/pdf/learnnet/classicdemos/mentosexplosion.pdf
3. Michael L. Corradinni is a professor at the University of Wisconsin School of Engineering. He published an article not specifically on the Mentos experiment, but on the topic of bubble nucleation. His articles is published online: http://wins.engr.wisc.edu/teaching/mpfBook/node27.html 4. Mythbusters is a popular Discovery Channel show involving several different aspects of science. One of their shows covered the science behind the Coke-Mentos reactions. A small segment of it can be viewed on the Discovery channel website: http://dsc.discovery.com/videos/mythbusters-diet-coke-and-mentos.html 5. Diet Coke and Mentos: What is really behind this physical reaction? by Tonya Shea Coffey describes an experiment performed at Appalachian State University, coverin many aspects of the reaction. Results, procedures and discussions can be viewed online: http://planck.lal.in2p3.fr/wiki/uploads/Photos/Activit%E9esClandestines/Coffey08_diet_ coke_and_mentos.pdf
Joe DeLucia 9-29-09
The Effect of Soda Temperature on the Height of Mentos Eruptions Several experiments have been conducted to test the famed Mentos- Diet Coke reaction, but few have tested this reaction to see if soda temperature influences the magnitude of the eruption. In a recent experiment, data proved to show that for every 10 degrees Celsius the Diet Coke was heated, the reaction rate was doubled (as well as every 10 degrees Celsius it was cooled the reaction rate was cut in half).1 It has also been noted that temperature plays a key role in the force and height of the reaction based geyser. 2 Based upon this data, as temperature increases or decreases, the height of the reaction also increases or decreases with it.
Height (Meters) 3
Height (Meters) 4
Mass Lost (grams) 5 21
All three of these result listings come from different experimenters who were all trying to discover the correlation of temperature and height in this infamous reaction. While all three results have different increments for temperature, different temperature to height ratios, and a different variable in one case, they all lean towards the same discovery. Comparing results 1 and 2, they both show that as temperature is increased, height also increased. Results 1 had an approximate 4 Kelvin increase with each level of its independent variable, allowing a chance to see a rhythmic pattern when compared to the height. Though no such pattern did clearly occur, with more levels of the independent variable, this very well may have been discovered. If the experimenter were to come up with a device more reliable then eyeto-ruler vision for the height results, perhaps a pattern might have been able to be detected. As for results 2, equal increments were not used, causing the data to be seemingly one dimensional. The height averages also seem oddly small to what they would normally be, being that Results 1 only used 5 Mentos per bottle and Results 2 used 8 per bottle. This is because the experimenters in Results 1 used a larger quantity of Diet Coke (2 Liters) 6 compared to that of the experimenter in Results 2(1 Liter) 7 showing that the quantity of reactants influences the overall reaction. It should be noticed that there is a .8m increase in 263K to 298K (35K difference) and a 2 meter increase in 298K to 308K (10K difference). This strongly contrasts with the theory stated in the beginning that with every 10 degrees Celsius warmer the soda gets, the reaction will double. Being that only one trial for each temperature was conducted by the experimenter for Results 2, 22
the results cannot strongly stand up against the previous statement, and may be somewhat inaccurate based on this (although this is only a theory). Results 3 measure temperature compared to mass lost instead of temperature to height. Again, this experiment only had one trial for each level of the independent variable and is therefore not fully conclusive. However, the idea of measuring the mass lost instead of height seems more valuable because it is much more exact in measuring the power of the reaction than estimating the height traveled. In general terms, these results support that of the other two graphs in the sense that with increased temperature comes a more active reaction. It can be concluded that with a higher temperature of soda, the reaction will be stronger and therefore, travel higher than that of a soda with a cooler temperature. This could be because the extra thermal energy naturally excites the molecules, and when the reaction takes place, some of this thermal energy is converted to kinetic energy, causing the height of the eruption to tower over a reaction that contains less thermal energy. A clear rhythmic pattern, however, cannot be traced from this data because of the lack of sufficient trials and equal increments that were used. If a sufficient amount of trials along with equal increments were to be experimented upon with temperature and height. The theory that an increase in 10 degrees Celsius will double reaction rate can be proved. 1
Guilford Journal of Chemistry, Vol. 1. “Warm Soda has a Dramatic Effect on the Height of a
Mentos Eruption” by Justin Husted. Originally from “Username: ‘Labmonkey’ yahooanswer.com January 10, 2008.” 2
Guilford Journal of Chemistry, Vol. 1. “Warm Soda has a Dramatic Effect on the Height of a
Mentos Eruption” by Justin Husted. Originally from www.stevespanglerscience.com mentos and soda temperature. 23
Guilford Journal of Chemistry, Vol. 2. “Six Meter Coke and Mentos Eruption Achieved By
Heating The Bottle” by Mary Melillo and Artem Guryanov. (Results) 4
Guilford Journal of Chemistry, Vol. 1. “Warm Soda has a Dramatic Effect on the Height of a
Mentos Eruption” by Justin Husted. (The Experiment) 5
“Diet Coke and Mentos: What is really behind this physical reaction?” by Tonya Shea Coffee.
(Results and Discussion) 6
Guilford Journal of Chemistry, Vol. 2. “Six Meter Coke and Mentos Eruption Achieved By
Heating The Bottle” by Mary Melillo and Artem Guryanov. (Procedure) 7
Guilford Journal of Chemistry, Vol. 1. “Warm Soda has a Dramatic Effect on the Height of a
Mentos Eruption” by Justin Husted. (Procedure)
Amanda Levy Period 8 9/29/09 How Temperature of Diet Coke Affects the Diet Coke and Mentos Reaction Review Although period 8 did not get the opportunities to test variables involving the Diet Coke and Mentos reaction, other resources have provided information about what happens when the temperature of the Diet Coke changes. One resource states that for every ten degrees Celsius the Diet Coke is heated, the reaction rate doubles, and for every ten degrees it is cooled, the reaction power is cut in half.¹ Even though this is stated in the Guilford Journal of Chemistry Volume One and then refereed to again in the Guilford Journal of Chemistry Volume Two, the original source is yahooanswers.com. To go beyond this unreliable claim, experiments done by Coffey, Justin Husted, Mary Melillo, and Artem Guryanov will be examined throughout the paper. Coffey investigated how the Diet Coke’s temperature effected the reaction by refrigerating one bottle for several hours prior to the experiment, and heating the other bottles in a water bath on a hot plate for about ten to twenty minutes.² The problem with this is that the bottle had to be opened before heating, and then closed again so that pressure could be released which prevented an explosion. Because the cold and room temperature bottles were not opened, the early release of some carbon dioxide gas might have caused the warm bottle to be less explosive. Another reason these results may be inaccurate is because she only performed one trial for each temperature. The results were examined only how much mass was lost, not the length or height of the explosion. Coffey’s found the following results: when the temperature of the Diet Coke was 47 degrees Celsius, the amount of mass lost was 1450 g; when the temperature of the Diet Coke was 38 degrees
Celsius, the amount of mass lost was 1350 g; and when the temperature of the Diet Coke was 6 degrees Celsius, the amount of mass lost was 1280 g.³ It should be noted that results may be not be precise because only one trial was done and only mass lost was recorded instead of mass lost, height, and time. Another approach to testing these materials is to submerge the bottles in different water temperatures to change the temperature of the Diet Coke. This eliminates the variable of letting carbon dioxide gas out before which could affect the end result of the explosion. This is what Justin Husted did in his experiment. ⁴ He reported his results in terms of the height of the reaction. Again, only one trial was done for each temperature which could result in unreliable data. Mary Melillo and Artem Guryanov had almost the same set up for their experiment (they also submerged bottles in water to change the temperature) except they only increased the temperature of two different bottles and did not investigate the effects of cooling the bottles. ⁵ Husted found the following results: the soda that was submerged in cold water and was 263 K lead to an eruption that was 20 centimeters high; the soda that was left in the classroom for 2 days to ensure average room temperature and was 298 K lead to an eruption that was 100 centimeters high; and the soda in the heated water that was 308 K lead to an eruption that was 300 centimeters high.⁶ It should be noted that results may be inaccurate because only one trial was done and only height was recorded as opposed to height, mass loss, and time. Melillo and Guryanov found the following results: the unheated bottle was 294 K and resulted in an explosion 4 meters high; the bottle heated to 298 K resulted in an explosion 5.5 meters high; and the bottle heated to 301 K resulted in an explosion 6 meters high.⁷ It should be noted that these results might not be accurate because height was measured in meters, only one trial was done for each temperature, and only height was recorded as opposed to height, mass loss, and time.
Conclusions It is very clear in all of the papers that as the temperature of the Diet Coke increases, the eruption size also increases. In Coffey’s research, there is a clear correlation in the data that shows as temperature is increased, the amount of mass lost increases. Coffey clearly states, “…hotter beverages result in a more explosive reaction.”⁸ This conclusion proves clear in both of the other article as well. In Husted’s research, the data shows a direct correlation that as the Diet Coke temperature is increased, the higher the explosion. Husted states, “By the results of the data, it is easily safe to conclude that the warmer the diet coke temperature, the more height the eruption gained.”⁹ Melillo and Guryanov’s data also prove true to this pattern; with every increase in temperature, there is an increase in the height of the explosion. Their paper states, “Our results clearly support the theory that using warmer Diet Coke will result in a higher Mentos eruption.”¹⁰ Even though all of these experiments had only one trial each, there was no exception to the theory that as the temperature increases, the eruption will also increase in any of the experiments. Because of this, it is safe to make the conclusion that as the temperature of Diet Coke increases, so does the eruption size.
Courtney Streeto September 27, 2009 Period 8
The Effect of Different Types of Carbonated Beverages on Mentos Eruptions
For years the eruptions created by the dropping of Mentos into sodas has been a phenomenon. The classic Mentos reaction has been made with the combination of Diet Coke and the original mint Mentos, because this mixture seems to produce the ideal reaction. In reality, however, other carbonated beverages seem to work just as well as the Diet Coke. It seems that most carbonated drinks will produce a suitable reaction. Most different types of carbonated drinks create a reaction, with the exception of energy supplements, because they lack the key ingredients for an explosion, potassium benzoate and aspartame.v These ingredients are included in diet soda, which is why diet coke is often chosen for the ideal reaction.v When tested, the JOLT energy drink did not respond to any number of Mentos, while diet soda will. Any non-diet drink also creates a lesser reaction. In tests with mint Mentos, the measurement of the height of the Coke explosion ranged from .125m in an experiment done by studentsv to 3.536m in an experiment designed by scientist Coffey2, making it the lowest nondiet measured reaction. Sprite also had a small reaction, .51m, which can also be said for its lack of key ingredients. 3
Tests were performed on different types of diet sodas, including Diet Coke and Diet Pepsi. In one of the few published peer-reviewed articles on Mentos eruptions, Coffey concludes that Caffeine Free Diet Coke has the highest explosion when tested with mint Mentos at 4.968m. In student experiments, however, sodas other than diet and none diet Coke were tested. One group of students saw that the smallest reaction of the diet drinks was Fresca, which traveled a height of .152m, followed by Diet Coke at .432m, then Sprite Zero at .787, and Diet Pepsi had the biggest explosion at .940m.v In another student experiment Diet Coke had an eruption of .85m and Sprite Zero had the highest reaction of 1.052m. 5 Yet another experiment with all diet carbonated beverages showed the following results: Sprite Zero had the smallest reaction with a height of .20m, followed by Diet Dr. Pepper at .22m, the second biggest reaction was from Diet Coke with .275m, and the greatest was Diet Tonic water with .29m.6 The results of these tests cannot be taken as proven fact because Mentos explosions are very rarely documented, and there need to be more published tests done to compare results with. For example, it cannot be deduced that all energy supplements have no reaction with Mentos based on the fact that JOLT did not have one. The conductors stated that there is no prior information about energy drink reactions. 7 More tests involving more energy drinks would have to be done in order to see if this type of carbonated drink can provide a reaction. Also, it is clear that each person conducting the experiments, from Coffey to students, received different results. This is because each person most likely had their own way of performing the experiment. Validity is in question, with things like whether or not the cap was on the soda, how many Mentos were used, expiration date, and factors that involved human error such as measurement. 29
However, when the results of every experiment are compared, it is obvious that a diet soda is much more explosive than a non-diet one. It may not be clear which diet soda is the best, but all will produce a reaction outdoing that of a regular soda. This is because each diet soda contains the active ingredients in a Mentos-soda reaction: potassium benzoate and aspartame.8 When searching for the ultimate eruption, one should use diet soda over any other beverage.
Sarah Jonathan Period 8
The Effect of Soda Temperature on Mentos Eruptions The Coke and Mentos eruption experiment is a popular activity but there is not often very much data collected on this topic. On e aspect of this reaction that has been tested is the effect of soda temperature on the size of the explosion. There have been multiple experiments done on the effect of soda temperature on explosion size that hypothesize that a warmer soda will result in a larger eruption. In one experiment done by Mary Melillo and Artem Guryanov state that â€œone experiment on the topic claimed that the reaction rate appears to double every ten degree in Celsius that you heat the diet Coke.â€?v This would be a significant increase in height if it were correct. In one experiment students tested bottles of diet coke with varying temperatures. They tested one bottle at 294 K, another at 298 K, and the last at 301 K. according to their report the first bottle at 294 K resulted in a 4 meter eruption, the second bottle at 298 K resulted in a 5.5 meter eruption, and the last bottle at 301 K resulted in a 6 meter high explosion.v This shows that when they increased the temperature by 7 K the height of the explosion increased by 2 meters. This is not quite the reaction that was predicted by the earlier mentioned experiment in that lab but it is still a large increase in the height of the explosion. In another experiment done by students the same procedure was followed except that Instead of measuring the temperature of the soda, the bottles were placed in water of a certain temperature for a constant amount of time. They had three different temperatures; these were coke submerged in 263 K water, coke left at room temperature or approximately 298 K, and coke
submerged in 308 K water.v In their results they stated that the height did increase with the temperature and the 263 K bottle had an explosion height of 20 centimeters, the 298 K bottle had an explosion height of 1 meter, and the 308 K bottle had an explosion height of 3 meters.v These results show that when there was a 45 K change in the substance the soda was heated in then there was a corresponding 280 centimeter change in the height of the explosion. In one other Experiment done by professor Coffey the experimental procedure was the same but the data collected was the amount of mass lost in the explosion not the height of the explosion. Coffey tested three temperatures of soda, these were at 320 K, 311 K, and 279 K.v Coffeyâ€™s results were similar to the results of the other two experiments. She stated that the higher the temperature of a bottle, the more mass lost in the explosion, which means the larger the explosion. In Coffeyâ€™s results the bottle of soda at 279 K lost 1280 grams, the next at 311 K lost 1350 grams, and the last at 320 K lost 1450 grams.v This shows that with a difference of 41 K there was a corresponding difference of 170 grams lost. Each of the above experiments had different results, however all of them demonstrated a clear relationship between the temperature of the bottle and the size of the explosion produced by this experiment. Although all of these tests had only one trial each when viewed together it is possible to conclude that the higher the temperature of the bottle of soda is, the bigger the resulting explosion will be. This is because if you view the three separate experiments as one, each could show one trial and the same conclusions would be made. In order to fully analyze however, more experiments with more trials would be needed.
Accidental Discovery of a Five Minute Mentos Eruption By Alysia Colandrea & Andrea Gava Summary: Originally, the design of this experiment was made to create a delayed mentos reaction by boiling mentos in water at a temperature of 473 K for 50 seconds. This heat would melt away the outer shell of the candy and any possible nucleation sites that could possibly be the reason for mentos explosions. As a result from the heat, rather than a delay in the explosion, a small reaction took place that stayed for an average of 5.17 minutes. Where a controlled mentos that was not boiled had an average eruption time of 31 seconds. Although the reaction of the boiled mentos didn’t drastically shoot into the air, the fizz continued for a very long period of time. Introduction: The mentos eruption is a well-known experiment where a mentos (one or more) is dropped into a soda—normally Diet Coke or Diet Pepsi—and a chemical reaction would occur where an eruption would over flow the bottle. The first well known Mentos Eruption was in September of 1999 on the David Letterman show, although the study had began around and in the 1980’s by teachers around the world even though they used various candies rather than mentos. Over the years, scientists and students have experimented with the Mentos Eruption attempted to create a sustained eruption that could last several minutes. It has been proved that melted mentos and diet coke will create a sustained eruption lasting consistently over one hour in duration. The reaction between Diet Coke and mentos usually produces a good reaction and is frequently tests, but if you were trying a mentos eruption to see how high it could go, it would be best to use Diet Pepsi instead of Diet Coke. Experimental Section: Our experiment was carried out by boiling 9 mint mentos and placing three in a 20 oz. bottle of Diet Pepsi, three more in another bottle, and the last three in a third bottle. We then watched the eruptions and timed how long they were carried out. We then did the experiment again with 9 mint mentos that were not boiled and timed them as well. Conclusion: In response to our original hypothesis that a heated/boiled mentos would created a longer reaction, we created a test in which consisted 9 mint mentos heated on a hot plate at 473 K and three 20 oz. bottles of Diet Pepsi. We then separated the heated mentos and placed three in one bottle, three in another, and three in the third having a steady constant of the number of mentos in each bottle. After watching the reactions go on for about five minutes, we concluded that the boiled mentos reaction was much longer than a controlled mentos (not boiled) which had an average eruption time of 31 seconds (rather than the 5 minutes and 17 seconds that the boiled mentos had. Mentos consist of many nucleation sites that are places where the carbon dioxide can make bubbles. A nucleation site can be a scratch on a surface, a speck of dust, or any place where you have a high surface area relative to volume. We figured that if the nucleation sites were boiled, they would evaporate or melt off of the mentos along with the outer layer, making the reaction more sustained. With a result of an eruption average time that is almost five minutes longer than the controlled mentos, our hypothesis was proved and we were found correct. Experimental Procedure: Materials: 1. 6 20 oz. Diet Pepsi Bottles at room temperature 2. 18 Mint Mentos 3. Hot Plate 4. Thermometer 5. Timer (Stopwatch) 6. Goggles 7. Access to water 8. Glass Beaker (100 mL in each trial) 9. Tweezers Procedure: 1. Put on your safety equipment, such as your goggles. 2. Line up all six soda bottles at room temperature in a line about one and a half meter apart from each other. 3. Separate the 18 mentos into 6 groups, each containing 3 mentos. 4. Turn the hot plate on
5. Place the glass beaker on top with the 100 mL of water 6. Place 3 groups of mentos into the beaker with water and wait until the water temperature goes up to 473 K. (or 200 ºC.) 7. Do these separately 8. Measure the temperature with your thermometer in Celsius and convert it to Kelvin, by adding 273 to your temperature. 9. Pull the each group of mentos out separately with your tweezers 10. Place one group of the boiled mentos in one of the Diet Pepsi bottles 11. With your timer record the time that the combination of soda and mentos erupt for. (you will know that there is a reaction, when the soda starts to bubble, and fizz, it does not have to erupt) 12. Write the time of the eruption down 13. Repeat steps 9- 11 with the other two groups of boiled mentos, and the other 2 soda bottles 14. Take the last 3 groups of mentos that should not have been boiled and separately place each group of them in the last 3 20 oz. soda bottles. Once again time the eruptions (this should not fizz, it should actually erupt) and record your information. 15. Once you have all of your information recorded figure out the time average of the boiled and non-boiled mentos, simply by adding all three trial of each and dividing them by 3. 16. Clean up Results: After we did the experiment we got three different eruption times which included a 4.49, 5.12, and 5.8 minute eruptions making an average of a 5.17 minute eruption. Mentos Reactions Trials Eruption Time Trail One Heated 4 minutes, 49 seconds Trial Two Heated 5 minutes, 12 seconds Trial Three Heated 5 minutes, 8 seconds Average Heated 5 minutes, 17 seconds Trial One Control 37 seconds Trial Two Control 24 seconds Trial Three Control 32 seconds Average Control 31 seconds
References: • Discovery of the World’s Longest Mentos Eruption: One Hour and Forty Minutes .Sam Taylor and Will Schaffer. Guilford Journal of Chemistry. Volume 2. Pages 38. (2008) http://chemistryadventure.com/Documents/guilford%20journal%20of%20chemistry%20volume%202.pdf • • •
Marek. (http://www.rimmkaufman.com/rkgblog/2007/12/21/steve-spangler/) Mentos. http://en.wikipedia.org/wiki/Mentos#Mentos_and_soft_drink_reaction Mentos Eruption, Speve Spanglers. (http://www.stevespanglerscience.com/experiment/00000109)
• Mentos Eruptions are increased by heating or Cooling the Mints. Rachel Cutler and Emma Smith. http://chemistryadventure.com/Documents/guilford%20journal%20of%20chemistry%20volume%202.pdf • Stories Tagged Nucleation Sites. http://www.sciencebuzz.org/buzz_tags/nucleation_sites
Observing the Surface of a Mentos By: Nick Latella and Allison Paradis Summary: In our experiment we observed the surface of a mentos using a high powered microscope and a camera adapter that attached to it to project the images that were under the microscope into a form that can be seen by more than one person at a time. We were trying to see what causes the eruption between the Diet Coke and the mentos by closely looking at the surface to see what imperfections there were. In the end we observed that when the mentos is exposed to the soda the cracks and fissures cause the CO2 to form a bubble which then dissolves the rough outer coating of the mentos. We believe this is due to what is called nucleation sitesv. Introduction: We only found a handful of experiments that had significant information and proof to back it up. One of them being the experiments done by Dr. Tonya Coffey, she and her team had done many experiments to figure out why the eruptions occur. To the naked eye the surface of the mentos candy is smooth but under a microscope the surface looks coarse. The coarse bumps are called nucleation site, each tiny nucleation site become a place where a bubble of CO2 gas can form and rapidly rise out of the soda. Multiply the one nucleation site by the many found on the mentos and you get thousands of bubbles forming continuously until the soda dissolves the outer layer and the mentos becomes smooth.v In Steve Spanglerâ€™s experiment he explains what happens when the mentos interacts with the diet coke. He says that as the mentos descends into the soda the CO2 gas fill the fissures in the candy and the bubbles formed carries the liquid up and out of the bottle.v Another experiment was done by the popular television group, Mythbusters, in which they identified the ingredients in the mentos and in the soda. After they had acquired these ingredients they tested each to see which would cause the eruption. They came up with; the CO2 gas and the aspartame in the soda (artificial sweetener), and the gelatin and gum arabic in the mentos, they concluded that these were the main ingredients in the reaction.v All of the previous experiment stated were valid and are proof of nucleation sites.
Experimental Section: In our experiment we observed the surface of a mentos by using a simple microscope. We started off by placing the mentos candy onto the slide. We had an external light source such as lamp, or in our case, a flash light, because the mentos candy was too thick for the microscope light to show through. We started on 40x magnification just to get the mentos in focus. Once we had this done we changed the magnification to 100x, from here we focused the image and attached the electronic camera adapter to the microscope. With this, we projected the images to a larger screen and then took pictures of the image seen. We used a normal digital camera and uploaded the photos to a computer. Using a disposable pipette, we added 2 35
drops to the mentos, waited for the small reaction to occur, then refocused the microscope and took pictures of the result. Materials:
A pack of Mentos candy Access to a microscope Access to an attachable electronic camera adapter One 1L bottle of diet coke One 12oz of diet coke Camera (preferably digital) Disposable pipette Lamp or flash light Balloon Adult supervision Procedure: 1. Gather materials 2. Open pack of mentos and place one mentos under the microscope and start at a low 40x magnification, get the image into focus. 3. Once the image is in focus move up to 100x magnification and again check to make sure the image is in focus. 4. Attach the electronic camera adapter to the microscope and connect it to a projector or a television screen. 5. Using a digital camera, take 2-4 pictures of the images shown on the screen. 6. Once done, use a pipette and fill it with diet coke. 7. Drop two drops of the diet coke onto the mentos and watch the physical reaction take place. 8. Record observations. 9. Once the reaction is over, dab dry the mentos with a paper towel and put back onto slide. 10. Take off the camera adopter. 11. Refocus the image by hand by using the 40x magnification until what is seen is half of the mentos that was affected by the soda and half that wasn’t. 12. Refocus with the 100x magnification. 13. Reattach the camera adopter. 14. Using the digital camera take 2-4 pictures of the images shown on the screen. 15. Record Observations.
Conclusion: After conducting our experiment we have concluded that the cause of the eruption is the CO2 filling the cracks and fissures which forms bubbles. These bubbles end up rapidly ascending upward and carrying the soda molecules with it forming the eruption that is so famously known. When the reaction has occurred the soda ends up dissolving the rough surface of the mentos down to a smooth area in which the reaction cannot again because there are no more cracks and fissures for the CO2 gas to form a bubble. As a follow up experiment, someone repeating this experiment can take a 1L bottle of soda and attach a balloon tit e top and then agitate the soda until all of the CO2 gas has escaped from the bottle and it becomes â€œflatâ€?. The when you drop the mentos into the bottle no reaction occurs, therefore the CO 2 gas is the main factor in the reaction. For further reading please refer to the references cited below.