Soda and Mentos Project

Soda and Mentos Project

Student’s Name

Institutional Affiliation

Soda and Mentos Project


The reaction between Soda and Mentos has not only elicited curiosity and disquiet, but also evoked the thought of the scientists, particularly of the younger generation. Notably, the phenomenon reaction has recently swept the internet and common in parties, and open places as the curious learners crave to understand why the mixture of the reagents leads to an explosion. Objectively, this research is scientific in nature and aims to explain and explore why when Mentos is added to Coke results to an explosion (Spangler, 2009). Descriptively, the explosion is always observed as a jet or froth of foam from a coke bottle that can eject up to several meters. If proper precautionary measures are not in place, it could lead to drenching of the experimenter. Therefore, the research answers the questions concerning the type of the reaction, why it explodes, and amongst other qualitative and quantitative analyzes and deductions. Methodologically, this simple experiment was conducted in an open laboratory setting. The primary goal was to make observations and record on the reagents, how they are mixed, the observable reaction features. After which, all possible inferences and analysis were made and discussed together. Most importantly, the laboratory setting must be spacious and proper clothing worn to avoid incidences of spillages and drenching (O’Brien, 2010). All said; this research was investigative and exploratory on why an explosion or fountain formation occurs when Mentos mint is added to a bottle of carbonated Coke beverage (Robinson, 2007).

Problem Statement

Indeed, there are many researches on chemical reactions that have been conducted and could simply be described as complex and entailing. However, little has been done to explain even what the children experience at home due to their curiosity. As such, this research is one of the simple reactions that result in startling observable changes when Mentos mint is dropped in a bottle of Coke (Robinson, 2007). Importantly, the research answers or explains the concept of explosion and the kind of reaction involved. Explicitly, the research helps the readers to understand the ingredients of the reagents in order to provide a comprehensive analysis of the observations (O’Brien, 2010). In addition, the observations and inferences are used to deduce on the applicability of the type of the reaction and to create some research gaps for subsequent studies.

Research Objectives

The research aimed to focus on the following objectives:

1.To identify the procedure and apparatus used in the reaction between Mentos and Coke and to provide the explanation for the stepwise scientific method

2.To investigate through observations and recording any observable changes during and after the reaction and then draw all the possible, analyzed conclusions based on the reaction.

3.To identify some of the factors that affect the reaction and to suggest the applicability of the reaction

Research Questions

1.What is the type or nature of the reaction between Mentos and Coke?

2.What are the observable changes that occur when a Mentos mint is added to a bottle of coke and the conclusions drawn?

3.What are other observable changes that might occur if other factors are altered such as temperature, size of the Coke bottle, or the amount of Mentos mints added?


In order to facilitate the analytical study, this research used the following parameters so as to measure the concepts involved in the reaction

1.Safety-safety of the reaction is qualitatively used as a measure of the level of fountain formation or explosion. Practically, in the research the height of the flotation or explosion provides the analogy of the nature of the reaction.

2.Time required- Time was used as a measure of the rate of reaction; that is, the time needed for the explosion to occur, recede, or stop. Hence, it defines the rate of reaction in relation to changes in contributing factors.

3.Observable changes- as a variable, it represents any of the notable features that occur as a result of the reaction.

4.Material Availability-shows whether the reagents are readily available and how do their dynamism affect the rate of reaction.

Notably, of the four main variables, time required, safety, and observable changes serve as the dependent variable. On the other hand, material availability such as the reagents, their quantity, and temperature represent the independent variable.


The research was based on the following null and alternative hypotheses:

H1-When Mentos mint is added to a bottle of carbonated Coke a physical reaction leads to an explosion and the reaction is influenced by other factors other than the reagents.

H0- When Mentos mint is added to a bottle of carbonated Coke a chemical reaction leads to an explosion, and it is not influenced by other factors.

Background Research

The reaction between Mentos mint and Diet Coke has raised a lot of startles and curiosity, particularly on the internet; however, it now entails a scientific explanation, which this research adds on. In particular, it is important to explain the nature of the reaction, and possibly, how the reaction would proceed under different circumstances. In essence, what is the cause of the explosion and what are the factors that might change the magnitude of the explosion and the rate of the reaction. According to Robinson (2007), this reaction has not only invoked its explanatory studies, but it heralds diversified explanations to other related reactions that involve gelatin and gum Arabic, caffeine, aspartame, and potassium benzoates (Robinson, 2007).

The aforementioned chemical compounds also happen to be the main ingredients in the soda and Mentos as reagents. Also, the debate has been on whether the reaction of the two reagents can be described as chemical or physical in order to classify the type or nature of the reaction. Nevertheless, Leavitt (2012) pointed out that the reaction is not chemical in nature since the whole notion is that the reagents just rearrange themselves instead of undergoing some chemical reaction. But it is important to note that the physical reaction is influenced by a number of factors that change the size of the explosion or the rate of the reaction. In order to understand the whole concept, it is imperative to discuss the nature of the reagents themselves.

Coffey (2008) pointed out that all carbonated beverages are packed with carbon dioxide gas (CO2) that bonds with water. A pressurized condition is maintained in the bottle so as to keep the CO2 dissolved. Therefore, when soda is poured into a glass, some of the CO2 escapes while others are trapped due to the water’s surface tension. As the gas tries to escape, the fizz or burp sound is produced. In addition, CO2 creates bubbles if the bonds between it and water have to be broken (Spangler, 2009). Therefore, a Mentos mint when added to the Coke, it helps to enhance the breakage of the bonds. Under a microscope, Mentos appear to be made up of tiny bumps of coats. The rough surface accelerates the rate of dissociation of the bonds; thus creating more bubbles and subsequent classic eruption (Robinson, 2007). Again, the speed of dropping the Mentos into the bottle also alters the rate of the reaction.

Similarly, O’Brien (2010) confirmed the findings of Coffey that the ingredients of Coke and Mentos, and the structure of the latter are the many factors that influence the extent to which CO2 create bubbles. Structurally, Mentos candy is made up of small surface pores that disrupt the polarity of the water molecules. As a result, multiple ideal nucleation sites are created, which make the molecules of the gas to congregate easily. Consequently, the bubbles’ buoyancy and growth eventually causes the bubbles leave the site of nucleation and move to the surface of the Coke (O’Brien, 2010). With progress, the bubbles continue to grow on the surface several times until a nice and foamy geyser is created.

Mentos is made up of gelatin and gum Arabic ingredients while the Diet soda has mainly sugar or aspartame and potassium benzoate. The interaction of the ingredients lowers the liquid’s surface tension, which in turn accelerate the formation and growth of the bubbles on the Mentos’ porous surface (Coffey, 2008). On the contrary, if the surface tension is high, the condition is seemingly difficult for the formation of the bubble since the bonding of CO2 and water is not easily broken (O’Brien, 2010). In a nutshell, the compounds like the gum Arabic act as surfactants that reduce the surface tension. Comparably, a diet soda reacts well than the non-dieted since aspartame is more than corn syrup or sugar in lowering the surface tension (Spangler, 2009). In sum, the reaction between Soda and Mentos is physical in nature, and it is influenced by the roughness of the Mentos, speed of adding the Mentos, and the addition of more surfactants.


As aforementioned, this research was experimental and conducted in a laboratory. As such, it is essential to mention the type of apparatus or materials that were used before outlining the stepwise procedure.

Materials List

Safety glasses

Two-Liter bottle of Diet Soda Pop (Diet soda is easier to clean)

One roll of Mentos (about 13 mints)

Loading tube for the Mentos

A geyser tube

Sticky notes

Video camera

Logger Pro for video analysis

Meter rule

Experimental Procedure

First wear the safety glasses and set up the camera in appropriate position to film the experiment

Use the meter rule to measure 1 and 2 meters vertically above the coke bottle so as to act as the reference height for the flotation and to enhance video analysis.

Open the Soda and then attach the geyser Tubing and put a trigger pin in the hole found at the base of the Tube.

Twist off the cap of the geyser tube and then add a pack of the Mentos into the tube.

Keep a considerable distance so as to avoid drenching from super fountain. As the Mentos drop bubble will start developing to the geyser

Pour the Coke remaining and compare the used Mentos to the unused in order to see the variation in the surfaces.

Repeat the experiment using the same procedure but increase the speed of adding the Mentors, use a larger bottle, and heated coke bottle. Use the stickers to mark the different experiments. Note the changes that happen in successive reactions.

Record all the observable changes then work on the subsequent analysis using the video images and Logger Pro then make conclusions.

Figure 1: Pictorial illustration of the experimental setting

Data Analysis and Results

Data revealed that carbonation of Coke was important. Also, many other items changed the rate of reaction and the height of the geyser. For example, when you increase the amount and speed of dropping the Mentos, the height of the geyser increased (Robinson, 2007). As the Mentos was being eaten up, more bubbles were formed to create the froth; thus the volume of the soda also reduced. Also, rougher Mentos increased the height of the geyser. In order to visualize the results, figure 2 and 3 serve as explanations.

Figure 2: Give a sample on how the geyser is produced.

Figure 3: Shows a plot of the approximate heights of the geysers against amount of Mentos added.


What causes the explosion as seen in Figure 1 is due to pressure release as the carbon dioxide escapes from the Coke bottle. Naturally, when a Coke bottle is removed, a fizzing sound is produced (Kilbane, 2010). However, this research adds that the rate of the escaping gas can be increased by adding aspartame in the Mentos. If the temperature of the reaction is increased, the bonds further break, leading to even more explosion. Also, rougher Mentos and increased speed of adding the Mentos accelerate the physical reaction (O’Brien, 2010).

The graph is a representation of the relation of the height of the geyser and amount of the Mentos added at a constant level of the Coke. If more Mentos are added, the nucleation sites are further created, and this accelerates the dissociation of the CO2-H2O bonding. More bonds break due to lowered surface tension of the water molecules (Kilbane, 2010). Therefore, the height of the geyser is directly proportional to the amount of Mentos added.

In conclusion, the reaction between soda and Mentos is physical in nature since no chemical change is involved. However, factors such as temperature, amount of the Mentos, speed of adding the Mentos, roughness of the Mentos affect the rate of the reaction and thus, the height of the geyser (Spangler, 2009). Notably, the research was experimental and conducted to investigate the aforementioned question and from the findings, the results are coherent with the alternative hypothesis. Nevertheless, further studies still needs to be carried out on other possible surfactants and how the concentration of the Coke affects the reaction.


Sincerely, I send my gratitude to my Chemistry and physics teachers for their guidance, my parent, and my school group member. Surely, this research is a composite of all your contributions. Thanks


Coffey, T. (2008). Diet Coke And Mentos: What Is Really Behind This Physical Reaction? American Journal of Physics,76(6), 551-557. From HYPERLINK “”

Kilbane, C. (2010). How to Make a Diet Coke & Mentos Bomb. Retrieved Jan. 8, 2015, from eHow:

Leavitt, L. (2012). Candy experiments. Kansas City, Mo: Andrews McMeel Pub.

O’Brien, T. (2010). Brain-powered science: Teaching and learning with discrepant events. Arlington, VA: NSTA Press.

Robinson, T. (2007). Everything Kids’ Magical Science Experiments Book: Dazzle your friends and family by making magical things happen!. Cincinnati: F+W Media.

Spangler, S. (2009). Getting Children Excited about Doing Real Science. Beyond the Fizz, 62-64. From HYPERLINK “”

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