science behind the mentos and coke experiment

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Mentos and Coke Experiment – How to Do It! [Full Guide]

Have you ever taken a can of soda, shook it up, and given it to your friend?

What happens?

Well, it’s probably not pretty. And you may not have a friend for a day or two until they forgive you.

But making soda explode is fun. And there is a way to make it really go boom if you have a few pennies and a bit of time on your hands.

Note – be sure to only try this experiment with a responsible adult!

It really only takes a few minutes to setup the mentos and coke volcano experiment. And it’s a great way to learn about chemical reactions.

It’s also a lot less work than your classic paper mache volcano. So, if you want some quick and easy fun, get some paper towels because we’re about to make a sweet mess.

What Will I Need For The Mentos And Coke Volcano?

There really aren’t that many supplies you need to make a mentos and coke volcano.

But here’s the list:

An outdoor area with no ceiling or roof

One roll of Mentos candies

A two-liter bottle of diet soda (diet soda makes for a much better reaction, but you can use regular soda if you like. It just won’t be nearly as awesome.)

A tube the width of the Mentos . It needs to be wide enough to use as loader for the Mentos

An index card (picture below)

The Mentos And Coke Volcano Experiment

Now it’s time to actually run the experiment, but first, we need to make a hypothesis.

The Hypothesis

The scientific method is an important way scientists make observations and come to conclusions.

Part of the scientific method is making a prediction called a hypothesis .

Write down what you think will happen when placing the Mentos in the soda bottles.

Do a little bit of research about the ingredients of Mentos and soda.

This will help you make an informed guess as to what will happen.

Now You Test The Hypothesis

In an experiment, you have two groups: an experimental group, and a control group.

Open the soda bottle, set it down and write down what you observe about it.

This will count as your control group. It’s what happens when you put nothing in the soda.

Now take the Mentos in your tube loader.

Put the index card on top of the tube loader and turn the tube upside down.

The candy should not fall out.

Be ready. The reaction happens fast, so don’t have your face over the bottle.

Place the index card and candies over the mouth of the bottle. Make sure the candies are in line with the mouth of the bottle.

You want the candies going in the bottle and not falling over the side.

Now remove the index card and let candies fall in and step away from the Mentos and coke volcano.

Write down what happened when you dropped the Mentos in the coke.

Did what you hypothesize happen? Compare your notes on the experiment to the control group.

Let us know what you observed in your science experiment!

FREQUENTLY ASKED QUESTION

1. can i use any type of mentos candy for the experiment.

Yes, you can use any type of Mentos candy for the experiment. The most commonly used Mentos candies are the original mint-flavored ones, but you can also use fruit-flavored or other varieties. The key factor is the rough surface of the Mentos candy, which helps to create nucleation sites for the carbon dioxide bubbles in the Coke. This happens because Coke contains dissolved carbon dioxide gas.

2. What happens if I use diet Coke instead of regular Coke?

If you use cold diet Coke instead of regular Coke in the Mentos experiment, you can still expect an explosive reaction. However, the reaction may not be as vigorous as with regular Coke. Diet Coke contains artificial sweeteners like aspartame, which may slightly affect the reaction. Nonetheless, the combination of Mentos and diet Coke can still produce a notable geyser, so it’s worth giving it a try. SO it will be the mentos geyser experiment.

3. Is the Mentos and Coke experiment suitable for children to try at home?

The Coke and Mentos experiment can be a fun and engaging activity for children to try at home. However, ensuring proper adult supervision and following safety precautions is important. Conducting the mentos experiment outdoors or in a well-ventilated area is recommended to avoid any potential mess or accidental spills. Additionally, remind children not to consume the Coke or Mentos mixture, as it is unsafe for ingestion. By taking these precautions, the Coke and Mentos experiment can provide children an educational and entertaining experience.

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June 14, 2012

Spurting Science: Erupting Diet Coke with Mentos

A carbonated challenge from Science Buddies

By Science Buddies

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Key concepts Chemistry Physics Materials science Carbonation Physical reactions Explosions Introduction Have you ever seen the Diet Coke and Mentos experiment that is all over the Internet and wondered what makes the reaction work? You might think that there is some ingredient in a Mentos candy that causes a chemical reaction with the soda pop, like the way baking soda reacts with vinegar. But the amazing eruption that takes place when Mentos are dropped into Diet Coke or other brands of diet soda pop is not a chemical reaction at all! Instead it is a physical reaction. That means that all of the pieces of the reaction are there, but that they are simply rearranged. It also means changing some factors may cause a larger or smaller physical reaction to take place. Background A carbonated beverage is packed full of dissolved carbon dioxide gas, which forms bonds with water. While the soda is in the bottle, the gas is kept in solution by the bottle's pressurized conditions. When you pour some soda into a glass, some gas escapes and forms foam, but most stays trapped by the surface tension of the water. But all those gas bubbles want to escape, making it no wonder that soda makes you burp! To create bubbles, the carbon dioxide needs to interact with itself, which means that the carbon dioxide's bonds with water in the Diet Coke must be broken. A Mentos candy can help with this. Although the candy may look smooth, if you looked at it under a microscope you'd see tiny bumps coating its entire surface. This rough surface allows the bonds between the carbon dioxide gas and the water to more easily break, helping to create carbon dioxide bubbles and cause the classic eruption. The speed at which the Mentos falls through the soda can affect how large the eruption is, and this can be tested by comparing whole with crushed Mentos, the latter of which are less dense. Materials •    Wax paper •    Cutting board •    Knife •    One roll of Mentos (at least eight candies) •    Two index cards •    Tape •    Two two-liter bottles of Diet Coke •    An outdoor area at least two meters from buildings •    Eye protection (safety goggles or glasses) •    Video camera with either a tripod or a helper to take the images (optional) Preparation •    Place a piece of wax paper on top of the cutting board. On the wax paper, carefully use a knife to crush and cut four Mentos candies into many small pieces. An adult may help you cut up the candies. What does the inside of the candies look like? •    Make a Mentos cartridge to hold the candies for you before you drop them into the Diet Coke bottle by rolling an index card into a tube, slightly larger than the diameter of a Mentos candy. Tape the tube together on the side. •    Be sure to wear eye protection when putting the candies into the cola! •    Wear clothes that you would not mind if they get splashed with a little soda pop—this activity can get a little messy! Procedure •    Place a Diet Coke bottle in an outdoor area, at least two meters from any buildings or anything hanging above the area, such as eaves, overhangs or wires. Make sure that the bottle is on a level surface and stably standing straight. Why do you think all of this is important? •    If you want to videotape the reactions, set up the video camera so that it has in its viewfinder the bottle and a height equivalent to at least the first story of a building. •    Carefully remove the cap from the bottle and place the flat index card on top, covering the hole. •    Add four whole Mentos candies to your cartridge, put on your eye protection, and start the video camera. •    Place your full cartridge on top of the flat index card. Line up where the opening of the bottle is with the opening of your cartridge. Quickly pull out the flat index card, releasing the Mentos candies into the bottle. Then step back without tipping the bottle over or disturbing the reaction. •    How quickly did the reaction start to happen, and how quickly did it stop? About how high did the eruption go? How much cola is left in the bottle? •    When the bottle stops spouting, stop recording. •    Remove the spent cola bottle and place a new full bottle in the same position, again making sure that it is level and stably standing straight. As with the first bottle, remove the cap and place the flat index card on top, covering the hole. •    Add your four crushed Mentos candies to your cartridge, pouring them in from the wax paper. Put on your eye protection and start the video camera. •    Like you did before, place your full cartridge on top of the flat index card, then line up where the opening of the bottle is with the opening of your cartridge. Quickly pull out the flat index card, releasing the crushed Mentos into the bottle, then step back without tipping the bottle over or disturbing the reaction. •    How quickly did the reaction start to happen, and how quickly did it stop? How high did the eruption appear to go? How much liquid is left in the bottle? Is it more or less than the amount that was left when you used whole candies? •    When the bottle stops spouting, stop recording. If you videotaped the reactions, you can watch your videos now. What do you notice from the videos? •    Which reaction went higher, the whole or the crushed Mentos? •    Extra : Find an exterior wall of a building with no windows and set a Diet Coke bottle at the base of the wall. Use a tape measure and blue painter's tape to mark off the height from the top of the bottle in meters. Then repeat this activity three times, with the bottle in front of the tape-marked wall, video taping it each time. When you review the recordings, use slow motion and pause the recording when the spout is at its maximum height. Using the tape marks in the background, estimate the height of the spout. Calculate the average height of the fountains for the whole and for the crushed Mentos . What is the difference in height of the eruptions? •    Extra: What other factors affect the size of the Mentos and Diet Coke eruption? You can try testing different kinds of carbonated beverages, different kinds of candies with different shapes and textures or using other things to start the reaction, like rock salt, pennies or dice. Which beverages, candies or other things cause the largest and smallest fountains? Why do you think this is? •    Extra: Do this activity again but instead of testing whole Mentos versus crushed, compare warm versus cold Diet Coke. Does temperature affect the eruption height? Observations and results Was the eruption higher when whole Mentos candies were used compared with crushed candies? Was less Diet Coke left in the bottle after the reaction with the whole candies compared with the crushed ones? In the Diet Coke bottle the Mentos candy provides a rough surface that allows the bonds between the carbon dioxide gas and water to break more easily, helping to create carbon dioxide bubbles. As the Mentos candy sinks in the bottle, the candy causes the production of more and more carbon dioxide bubbles, and the rising bubbles react with carbon dioxide that is still dissolved in the soda to cause more carbon dioxide to be freed and create even more bubbles, resulting in the eruption. Because Mentos candies are rather dense, they sink rapidly through the liquid, causing a fast, large eruption. The crushed Mentos candies, however, are not as dense as the whole ones, which causes them to sink more slowly, creating a relatively small cola fountain, which should also leave more liquid in the bottle than the larger eruption with whole Mentos candies did. Cleanup Hose off any part of a building that was splashed with Diet Coke. If you try this project with regular Coke, the eruption should still happen but its sugary content may make cleaning more difficult. More to explore Physicists Explain Mentos–Soda Spray from Scientific American Science of Mentos–Diet Coke explosions explained from New Scientist The Science of Coke and Mentos from EepyBird.com Why do Mentos mints foam when you drop them into soda pop? from General Chemistry Online Coke® & Mentos®—Nucleation Goes Nuclear! from Science Buddies

This activity brought to you in partnership with Science Buddies

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Science of Mentos-Diet Coke explosions explained

By Hazel Muir

12 June 2008

Scanning electron microscope images show the roughness of mint Mentos (top and bottom left) and fruit Mentos (top and bottom right), the scale bars representing lengths from 20 to 200 micrometres

(Image: T Coffey/Dewel Microscopy Facility/AAPT)

The startling reaction between Diet Coke and Mentos sweets, made famous in thousands of YouTube videos, finally has a scientific explanation. A study in the US has identified the prime factors that drive the fizzy plumes from Coke bottles: the roughness of the sweet and how fast it plummets to the bottle’s base.

“If you drop a pack of Mentos into a bottle of Diet Coke, you get this huge fountain of spray and Diet Coke foam coming out,” says Tonya Coffey , a physicist at Appalachian State University in Boone, North Carolina. “This was a good project for my students to study because there was still some mystery to it.”

When mint or fruit Mentos are dropped into a fresh bottle of Diet Coke, a jet of Coke whooshes out of the bottle’s mouth and can reach a height of 10 metres. Theories abound as to why this happens, with some bloggers speculating that it is an acid-base reaction because Coke is acidic.

Experiments in a 2006 edition of the Discovery Channel programme Mythbusters suggested the chemicals responsible for the reaction are gum arabic and gelatine in the sweets, and caffeine, potassium benzoate and aspartame in the Coke. But there have been no rigorous scientific studies of the reaction until now.

Fizzy liquids

To find out more, Coffey and a team of students tested the reactions between Diet Coke and fruit Mentos, mint Mentos, and various ingredients such as other mints, dish-washing detergent, table salt and sand. They also compared reactions using other fizzy liquids such as caffeine-free and sugary colas, as well as soda water and tonic water.

All the reactions took place in a bottle angled at 10° off vertical and the fountain trajectories were recorded on video. The team also investigated the total mass lost in the fountain and the influence of the sweet’s surface roughness.

The results showed that Diet Coke created the most spectacular explosions with either fruit or mint Mentos, the fountains travelling a horizontal distance of up to 7 metres.

But caffeine-free Diet Coke did just as well, suggesting that caffeine does not accelerate the reaction, at least at the normal levels in the drink.

Measurements of the pH of the Coke before and after the experiments showed that its acidity did not change, ruling out the idea that a simple acid-base reaction drives the fountains.

Instead, the vigour of the jets depends on various factors that affect the growth rate of carbon dioxide bubbles.

The rough, dimply surfaces of Mentos encourage bubble growth because they efficiently disrupt the polar attractions between water molecules, creating bubble growth sites.

Rough candy

“Water molecules like to be next to other water molecules, so basically anything that you drop into the soda that disrupts the network of water molecules can act as a growth site for bubbles,” Coffey told New Scientist . “And if you have rough candy with a high ratio of surface area to volume, then there’s more places for the bubbles to go.”

Low surface tension also helps bubbles grow quickly. Measurements showed that the surface tension in water containing the sweetener aspartame is lower than in sugary water, explaining why Diet Coke creates more dramatic fountains than sugary Coke.

Another factor is that the coatings of Mentos contain gum arabic, a surfactant that further reduces surface tension in the liquid. Rough-surfaced mints without the surfactant did not create such large fountains.

Mentos are also fairly dense and sink rapidly, quickly creating bubbles that seed further bubbles as they rise. Crushed Mentos that fell more slowly created puny fountains that only travelled about 30 centimetres.

“Middle-school teachers are getting their students out onto the baseball field next to their school and doing this reaction, and their students love it,” says Coffey. “It’s a great way to get students excited about science and learn something new.”

Journal reference : American Journal of Physics , DOI: 10.1119/1.2888546

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Why Do Mentos Explode in Coke?

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The chemical reactions involved in dropping mentos candies into a bottle of diet coke make quite the spectacle! Soda geysters, which can reach as high as ten meters, were a popular subject for viral videos in the early 2000's, but the science behind the spectacle remained a mystery until 2008.

Chemistry and Physics

Applications.

Many people speculated that the geyser was the result of an acid base reaction , given the low pH of soda. However, none of the ingredients in mentos are basic, and the experiment works to some degree with any type of soda and any type of candy.

Mentos candies are not as smooth as they appear to the naked eye. They are covered in bumpy craters, which increases the total surface area. A Mentos dropped into a bottle of soda acts as a surfactant , meaning it reduces the surface tension of the soda. Water molecules are polar and attracted to each other. Anything that breaks them apart allows for bubbles of carbon dioxide gas to form in the solution. A rougher candy surface translates to more places for bubbles to grow, or more nucleation sites . Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.

This is essentially speeding up the process that makes sodas fizzy. Bottled sodas are kept under pressure so that more carbon dioxide can be forced into solution. When the pressure is released, the carbon dioxide is forced out of solution and makes little gas bubbles. So, if you open a bottle of soda gently, you get a pleasant beverage. If you shake the can first, you disrupt the solution and get a face full of soda. And if you add a big enough surfactant, you get a geyser. It's the same chemistry, but a different magnitude.

The two biggest factors affecting the geyser are the roughness of the candy used and the rate at which it sinks to the bottom of the soda bottle. [1] Other factors that affect the growth rate or total number of carbon dioxide bubbles also changed the geyser's height, such as temperature and the original surface tension of the soda. Diet Coke makes a better spectacle than regular Coca-Cola because both aspartame and benzonatate (a preservative used in artificially sweetened drinks) lower surface tension more than sugar does.

Mixing mentos and soda makes a great science demonstration for students studying gases, thermodynamics, fluid dynamics, surface science, and the physics of explosions among other chemistry and physics concepts. [1]

Tonya Coffey, a professor at Appalachian State University, used the experiment to give her undergraduate physics class a real-world research experience as one of their laboratory assignments. The project was eventually published in the American Journal of Physics . Though the manuscript is behind a paywall, a presentation that Dr. Coffey made about the experience is available on the schools website. [2]

The force exerted by the soda stream can be harnessed to do work. One enterprising group made a mentos and diet coke-powered rocket. However, the practical applications of this reaction are limited by the sticky mess it makes.

The engineer explains that the yellow nose cap is full of mentos, while the body is full of pressurized diet coke. Watch the full video for a more detailed explanation. [3]

There is an urban legend that eating mentos while drinking soda could cause a person's stomach to burst. However, most of the carbonation is released from the soda as it is being drunk, so the pressure is lower and carbon dioxide is less likely to nucleate. Additionally, the stomach has a couple ways of expelling excess gases.

A mint-flavored mentos makes a geyser 5 meters high and a fruit-flavored mentos makes a geyser 2 meters high when the two candies are put into identical bottles of soda under identical experimental conditions. What is the most reasonable hypothesis to explain the difference?

• Coffey, T. (2008). Diet Coke and Mentos: What is really behind this physical reaction?. American Journal of Physics , 76,551 .
• Coffey, T. Diet Coke and Mentos . Retrieved from http://www.appstate.edu/~coffeyts/DietCokeandMentos.pdf
• Milleaccendini, Y. Youtube . Retrieved March 18, 2016, from https://www.youtube.com/watch?v=mb6neBVtvsE

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The Infamous Coke and Mentos Experiment

September 11, 2014 By Emma Vanstone 1 Comment

The science experiments my children talk about for months afterwards are generally the messy ones, like our splatter patterns , glow in the dark oobleck ,  baking soda experiments and the well known coke and mento experiment .

If you try this classic chemis t ry experiment definitely do it outside as it’s VERY messy and sticky. Sometimes you’ll see it called a coke and mento geyse r, as the eruption looks like a geyser!

Coke and Mentos Experiment

You’ll need:.

Coke or other fizzy soda

Instructions

We dropped two Mentos into a bottle of normal Cola and Diet Cola. I used the cheapest brands available in our local supermarket.

Once you drop the Mentos into the coke, stand back as it’s VERY explosive. The trick is to drop the mento in as fast as you can. If too much of the fizz escapes before you add the mento the reaction won’t be as good.

What happens when Coke and Mentos mix?

There are several theories, but it’s thought that the many small pores on the surface of the mento speed up the release of carbon dioxide (CO 2 ) gas from the soda as they give a larger surface area for the reaction to occur over, causing foam to erupt at a super fast rate.

Which soda works best with Mentos?

Any fizzy drink will produce a similar effect, but diet drinks seem to work best, as we found in our investigation. This is most likely due to the particular chemicals in diet drinks.

The reaction isn’t a chemical reaction but a physical reaction! The molecules haven’t been chemically changed, just re-arranged!

See Steve Spangler for a much more thorough explanation of this very cool experiment .

Does the number of mentos affect the height?

More Mentos candies should mean a better explosion, but there is a limit to how many will actually make a difference. We found 7 to be the maximum number we could drop in at once.

More Coke and Mentos Eruption Ideas

Investigate to find out if the type of fizzy drink matters. Does diet soda make a taller geyser?

Try lots of different sodas and diet sodas.

Test fruit-flavoured Mentos instead of mint flavoured.

Find out if the number of mentos affects the height of the geyser.

Investigate to discover what would happen if you left the top off the Cola for a few minutes before adding the Mento.

Use the reaction to power something? Maybe a LEGO car?

Design a device to drop several mentos into the bottle at the same time. Can you find out what the optimum number of mentos for a 2-litre bottle of soda is?

Last Updated on April 9, 2024 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

December 17, 2019 at 7:20 pm

It will also work better the warmer the soda is

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The Amazing Science Behind Coke + Mentos

What causes Coke to explode when Mentos are added to it? One would think that there must be a chemical reaction that causes the Coke and Mentos reaction to be so attractive and satisfying. It’s actually not chemical! Let us dig deep into the experiment to understand why it’s not a chemical reaction.

The carbonated drinks’ fizz comes from carbon dioxide added to the bottles at high pressure. 2-liter Diet Coke contains around 12-15 grams of dissolved carbon dioxide. The gas tries to escape and form bubbles around any irregular surface, called a nucleation site. Mentos also have nucleation sites because they are not as smooth as they appear. When added to Coke, the dissolved gas pushes the liquid out of the container at a super-fast speed in the form of bubbles. The candies simply catalyze the release of gas from the Coke bottle. Therefore, the chemical reaction between Coke and Mentos, in reality, is a physical reaction.

No matter how messy or sticky the experiment is, there are only two ingredients required to make this geyser. One bottle of 2-liter fizzy drink, preferably Diet Coke, and Mentos are needed in an adequate quantity to give a spectacular reaction. For a 2-liter bottle of Coke, at least five Mentos are good enough. Moreover, all Mentos must be added to the drink simultaneously, giving each of them equal time to create an effect. As Mentos candies are dropped into the Coke bottle, there is an explosion seconds later, and a “Mentos Coke Fountain” goes high up in the sky.

Remember growing up with the advice that eating Mentos while drinking soda can burst a person’s stomach? Actually, it’s not that dangerous because most of the carbonation is released as a person drinks the soda. The pressure is lower and carbon dioxide does not nucleate. However, kids are not advised and should not do such a thing, as their stomachs are not powerful enough to absorb this physical reaction.

In easier words, Coke contains carbon dioxide, which gives the drink its fizziness. As a Mentos candy is dropped inside the bottle, the carbon dioxide molecules attach to it. In addition, the tiny pores on a larger surface area of Mentos ultimately speed up the release of the gas, which creates bubbles that rise to the surface and push the drink, eventually resulting in a blast.

The highest recorded explosion has been of Mentos and Diet Coke when the fountain touched up to 10 meters. Most people believe that the more Mentos are added to Coke, the bigger and higher the eruption will be. However, the number of Mentos that will make a difference is limited. Through various investigations, it has been deduced that seven Mentos are the max.

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Mentos and Coke Experiment: Fun Fizzy Science for All Ages

• SuchScience Staff
• August 16, 2024

The Mentos and Coke experiment is a fun and exciting way to explore science.

Kids love watching the massive soda geyser that erupts when Mentos candies are dropped into a bottle of Diet Coke.

This simple experiment demonstrates the principles of nucleation and carbon dioxide release.

It makes a perfect science fair project for students of all ages.

The reaction between Mentos and Coke is not a chemical one, but rather a physical reaction.

When you drop the Mentos into the soda, they act as nucleation sites for the carbon dioxide bubbles in the drink.

This causes a rapid release of the gas, creating a foamy explosion that can shoot several feet into the air.

To try this experiment at home or for a science fair, you’ll need some Diet Coke and Mentos candies .

You can also experiment with different types of soda and candy to see how they affect the reaction.

Remember to do this outdoors and wear old clothes, as it can get messy!

What This Article Will Teach You

The Science Behind the Eruption

The Mentos and Coke eruption involves some fascinating scientific principles .

It’s all about chemical reactions , carbon dioxide , and the unique properties of diet soda.

Understanding the Chemical Reaction

When Mentos candies are dropped into Diet Coke, a dramatic reaction occurs .

The surface of the Mentos is covered in tiny pits and craters.

These act as nucleation sites, giving the carbon dioxide in the soda a place to form bubbles.

The rough texture of Mentos also breaks the surface tension of the liquid.

This allows more carbon dioxide to escape from the soda quickly.

Mentos candies sink rapidly to the bottom of the bottle.

As they fall, they create a trail of bubbles.

This sets off a chain reaction, causing more and more carbon dioxide to be released.

The Role of Carbon Dioxide

Carbon dioxide is the key player in this bubbly show.

In soda, CO2 is dissolved under pressure.

When you open a bottle, some of this gas escapes as fizz.

The Mentos cause this process to happen much faster. Thousands of tiny bubbles form on the candy surface.

These bubbles quickly rise to the top of the bottle.

As the bubbles rise, they pick up more carbon dioxide along the way.

This creates a rapid expansion of gas.

The result? A powerful jet of soda shooting out of the bottle!

The Significance of Diet Soda

Diet soda works best for this experiment.

But why? It’s all about the ingredients.

Diet Coke creates the most impressive eruptions .

This is due to its artificial sweeteners.

These chemicals lower the surface tension of the liquid more than regular sugar does.

Lower surface tension means bubbles can form more easily.

It also allows the carbon dioxide to be released faster.

The lack of sugar in diet soda also plays a role.

Sugar makes the liquid more viscous.

In diet soda, the lower viscosity lets the bubbles rise more quickly.

Preparation and Materials

Getting ready for the Mentos and Coke experiment is fun and easy.

Let’s look at what you need and how to stay safe.

Gathering Necessary Items

To do this cool experiment, you’ll need a few things:

• A 2-liter bottle of Diet Coke (or regular Coke)
• A pack of Mentos candy
• A large open space outside
• A measuring tape
• Paper towels for cleanup

It’s best to use Diet Coke because it makes a bigger splash.

Make sure the soda is at room temperature for the best results.

You might also want a geyser tube to drop the Mentos in quickly.

If you don’t have one, you can make a paper tube at home.

Safety First: Protecting Yourself

Safety is super important when doing any experiment.

Here’s how to stay safe:

• Wear safety goggles to protect your eyes.
• Do the experiment outside in an open area.
• Have an adult help you and watch.
• Keep a safe distance after dropping in the Mentos.

The Diet Coke and Mentos reaction can shoot up several feet high.

Make sure there’s nothing nearby that could get wet or sticky.

It’s also a good idea to have water nearby to wash off any soda that might get on you.

Remember, have fun but always put safety first!

Conducting the Experiment

Let’s dive into the fun part – doing the Mentos and Coke experiment! We’ll go through the steps, measure the results, and record what we see.

Step-By-Step Instructions

Find a flat outdoor space away from people and objects.

Place a 2-liter bottle of Diet Coke on the ground. Make sure it’s at room temperature.

Create a Mentos stack using 5-7 candies. You can use a paper tube or geyser tube to hold them.

Open the Diet Coke bottle quickly.

Drop the Mentos stack into the bottle and step back fast!

Watch the soda erupt into a foamy geyser.

Stay safe by wearing old clothes and eye protection.

Have a friend ready with a camera to capture the action!

Measuring the Effect

To turn this into a real experiment, we need to measure our results.

Use a tape measure to mark heights on a nearby wall before starting.

Set up a video camera to record each eruption.

After each try, measure how high the soda shot up.

Count how long the reaction lasted using a stopwatch.

Try changing one thing at a time, like using different sodas or Mentos flavors.

This helps see what affects the eruption most.

Recording Your Observations

Keep track of what happens in each test:

• Write down the type of soda and Mentos used.
• Note the eruption height and duration.
• Describe how the geyser looked – was it thin or wide? Foamy or bubbly?
• Record any variables you changed, like soda temperature or number of Mentos.
• Take photos or draw pictures of each eruption.

Use a simple table to organize your data.

This makes it easy to compare results later.

Exploring Variables

The Mentos and Coke experiment has many factors that can change the results.

Let’s look at how temperature, the number of Mentos, and different sodas affect the reaction.

Temperature’s Impact on the Reaction

Temperature plays a big role in how the Mentos and Coke react. Cold Diet Coke usually makes a bigger splash than warm soda.

This is because cold liquid can hold more dissolved gas.

When the soda is cold, it has more carbon dioxide bubbles trapped inside.

These bubbles are what create the fun eruption.

Warm Diet Coke, on the other hand, has less gas and might not make as big of a mess.

Try this: Get two bottles of Diet Coke.

Put one in the fridge and leave one out.

Then, drop Mentos in each and watch the difference!

Adjusting Quantity of Mentos

The number of Mentos used can change how high the soda shoots up.

More Mentos usually means a bigger reaction.

Each Mentos candy has tiny bumps on its surface.

These bumps give the carbon dioxide bubbles places to form.

More Mentos means more places for bubbles, which leads to a bigger eruption.

Here’s a fun experiment:

• Try 1 Mentos in one bottle
• Use 3 Mentos in another bottle
• Drop 5 Mentos in a third bottle

Watch how the height of the spray changes with each test!

Type of Soda Used

Not all sodas react the same way with Mentos. Diet Coke often works best , but other sodas can be fun too.

Regular soda has sugar, which can slow down the reaction.

Diet sodas don’t have this problem, so they usually create bigger eruptions.

The amount of carbonation in the soda also matters.

More carbonation means more bubbles and a bigger reaction.

Try these sodas to see the differences:

• Regular Coke

Remember to do this experiment outside.

It can get very messy!

Physical vs Chemical Reactions

The Mentos and Coke experiment shows how fizzy reactions can happen without changing what things are made of.

It’s all about bubbles and how they form quickly.

The Physics of Fizz

When Mentos drop into Diet Coke, they don’t mix or change chemically.

Instead, they cause a physical reaction .

The candy’s rough surface has tiny spaces that act as nucleation sites.

These spots let carbon dioxide bubbles form super fast.

Diet Coke already has lots of CO2 dissolved in it.

The Mentos just give those bubbles a place to start growing.

It’s like when you shake a soda can – the bubbles were there all along, but now they have a reason to come out.

This reaction happens so quickly because there are so many bubble-starting spots on each Mentos candy.

The more candies you add, the bigger the eruption!

Busting Myths with Science

Some people think Mentos and Diet Coke mix chemically, but that’s not true.

No new substances form in this experiment.

The ingredients don’t change .

It’s all about rearranging what’s already there.

Here’s what really happens:

• CO2 breaks away from water molecules
• Bubbles form on Mentos surfaces
• Bubbles grow and rise quickly
• Pressure builds up
• Soda sprays out of the bottle

This isn’t like baking soda and vinegar, which do react chemically.

With Mentos and Coke, it’s just physics at play.

The candy could be replaced with other rough items and still cause a similar effect.

Science Experiment Tips

Good science experiments need planning and careful steps.

They also need to be done more than once to make sure the results are right.

Creating a Hypothesis

A hypothesis is a guess about what will happen in an experiment.

It’s based on what you already know.

For the Mentos and Coke experiment, a student might guess how high the soda will shoot up.

To make a good hypothesis:

• Think about what you know about Coke and Mentos
• Ask questions like “What will happen when they mix?”
• Write down your best guess

A clear hypothesis helps focus the experiment.

It gives a clear idea of what to look for when doing the test.

The Importance of Replication

Doing an experiment once is not enough.

Scientists repeat their tests many times.

This is called replication.

It helps make sure the results are real and not just by chance.

For the Mentos and Coke experiment:

• Do the test at least three times
• Keep everything the same each time
• Record the results carefully

Replication can show if the results are the same each time.

If they are, it means the experiment is more likely to be correct.

This is a key part of the scientific method used in STEM fields.

Fun with Mentos and Coke

The Mentos and Coke experiment is a blast for kids and adults alike.

It combines science with excitement, creating memorable experiences for everyone involved.

Interactive Activities for Kids

Kids love the Mentos and Coke experiment .

It’s a great way to get them excited about science.

They can make predictions about how high the foam will shoot up.

To make it more interactive, kids can build a Mentos tower to drop all the candies at once.

This adds an engineering element to the experiment.

For a science fair project, children can test different variables.

They might try different soda brands or Mentos flavors.

Measuring the height of the fountain adds a math component.

Safety is key.

Adults should supervise and help kids wear safety goggles.

It’s best to do this experiment in an outdoor area with a flat surface.

Hosting a Mentos and Coke Party

A Mentos and Coke party is a fun way to celebrate science.

Guests can take turns setting off the reaction.

It’s sure to create lots of laughs and excitement.

Set up different stations with various soda types.

Diet sodas often create the biggest reaction.

Provide a variety of Mentos flavors for guests to try.

Create a competition for the highest fountain.

Use a measuring tape or mark heights on a wall.

Give prizes for the most impressive eruptions.

For decorations, use soda bottles and Mentos-themed items.

Serve snacks that complement the theme, like fizzy drinks and candy.

Remember to have cleaning supplies ready.

The foam can get messy, but that’s part of the fun!

Physics in Action

The Mentos and Coke experiment shows some cool physics at work.

It’s all about pressure, tiny bubbles, and the special surface of Mentos candy.

Pressure and Explosions

When Mentos drop into a bottle of Coke, it creates a big reaction.

The soda is full of carbon dioxide gas under pressure.

This gas wants to escape.

Mentos give the gas lots of places to form bubbles.

As bubbles form fast, pressure builds up.

The bottle can’t hold it all in.

This leads to a big eruption of fizzy soda .

It can shoot up several feet high! The more Mentos used, the bigger the explosion.

Mentos Textures and Gas Bubbles

Mentos have a unique surface that helps make bubbles.

Under a microscope, you can see tiny bumps all over the candy.

These bumps are perfect spots for gas bubbles to form.

Scientists call this process nucleation.

It’s like giving the carbon dioxide a helping hand to turn into bubbles.

The rough texture of Mentos breaks the bonds between gas and liquid in the soda.

This makes it easy for lots of bubbles to form very quickly.

As bubbles rise, they make more bubbles.

This chain reaction is what causes the big, foamy explosion we see.

Personalizing the Experiment

The Mentos and Coke experiment can be customized in fun ways.

Changing up the ingredients and methods can lead to surprising results and higher eruptions.

Creative Variations to Try

Try using different soda flavors like cherry or vanilla Coke.

The taste difference might affect the reaction.

Swap out Mentos for other candies like Skittles or Lifesavers.

These can create unique eruption patterns .

Experiment with soda temperature.

Warm soda tends to fizz more than cold.

For a colorful twist, add a few drops of food coloring to the bottle before dropping in the Mentos.

Make it a competition! Set up multiple bottles and see which combination creates the biggest geyser .

This can be a fun activity for science fairs or backyard parties.

Tweaking for Maximum Height

To reach new heights, focus on the Mentos. Crushed Mentos can create a faster, more explosive reaction than whole ones.

Try different shapes too – flat Mentos might sink faster.

The way Mentos are dropped matters.

Using a paper tube can help get more Mentos in quickly.

This increases the reaction speed and potential height.

Bottle shape affects the eruption.

Narrower openings can create more pressure, leading to higher geysers.

Some experimenters use specially designed caps to control the flow.

For measuring, set up a marked wall behind the bottle.

This helps track the maximum height reached by each eruption.

Cleanup and Environment

The Mentos and Coke experiment can create quite a mess.

It’s important to plan for cleanup and think about the impact on the environment .

A little preparation goes a long way in making the aftermath easier to handle.

Managing the Mess

Doing the experiment outdoors is the best way to minimize cleanup.

If that’s not possible, use a large plastic tub to contain the eruption.

Have plenty of towels or rags ready.

Wet wipes are great for sticky surfaces.

Put down a tarp or garbage bags to protect the ground.

Wear old clothes you don’t mind getting dirty.

Safety goggles are a good idea to protect eyes from splashes.

After the fun, rinse the area with water to wash away sticky residue.

Pick up any Mentos wrappers or other trash.

A squeegee can help remove liquid from hard surfaces quickly.

Environmental Considerations

While fun, this experiment uses up resources.

To be more eco-friendly, try these tips:

• Use the smallest bottle size needed for your demonstration.
• Collect the liquid aftermath in a bucket. Then, use it to water plants (when diluted) or clean outdoor areas.
• Recycle the empty Coke bottle and Mentos container.
• Choose a grassy area for the eruption. The soil will absorb the liquid, reducing runoff.

Consider explaining the environmental impact to participants.

It’s a good chance to talk about responsible science and conservation.

The Secrets of the Coke and Mentos Fountain

It’s one of the most popular science demonstrations: Pop a handful of Mentos candies into a bottle of Coke, and a fountain of bubbles rapidly spurts from the open bottle, often over a metre into the air. Originally the explanation for the effect was thought to be quite simple. However, scientists are finding that there’s more to this spectacular demonstration than meets the eye.

The basic science of the Coke and Mentos reaction is fairly straightforward. In fact, it’s not really a reaction at all – or at least it’s a physical reaction rather than a chemical one. Carbonated drinks get their fizz from dissolved carbon dioxide, which is pumped into the bottles at high pressure to make it dissolve. Your average two litre bottle of Coke will contain about fifteen grams of dissolved carbon dioxide.

When you open a bottle of a carbonated drink, you release the pressure. As the carbon dioxide is less soluble at lower pressures, it starts to leave the drink in the form of small bubbles. When you add Mentos to the bottle, you’re drastically speeding up this process. Though the surface of a Mentos candy may look smooth, at a microscopic level it’s full of pits, peaks, and craters, like a miniature version of the surface of the moon. These pits, peaks, and craters are referred to as nucleation sites. They provide a surface for the carbon dioxide bubbles to form on, and allow them to form much more rapidly.

That paltry fifteen grams of carbon dioxide in the bottle might not sound like much, but as it comes out of solution in the bottle it can expand to take up up to 8 litres in volume. This explains why the drastically increased formation of bubbles after adding Mentos to the bottle leads to the geyser of Coke shooting out of the top moments later – there’s nowhere else for the bubbly liquid to go but up!

Science teachers are well aware that some types of carbonated drinks work better than others for this demonstration; for example, Diet Coke usually gives a higher fountain than regular Coke. Previously, scientists have tried to investigate why this is , and they suggest that the artificial sweeteners in diet forms of carbonated drinks, specifically aspartame and benzoate, might be responsible. Their suggestion was that these compounds lower the surface tension of the liquid, which allows bubbles to form quicker. Sugar-sweetened drinks tend to be more viscous, which likely slows bubble formation, leading to smaller fountains than for their diet counterparts.

More recently, chemists at Spring Arbor University in the United States tested a range of different carbonated drinks and found that the height of fountains varied between different products. Generally, they found that carbonated water gave the smallest geysers, with sugar-sweetened beverages giving better results, and diet beverages better still. They suspected other compounds dissolved in the drinks might be affecting fountain height, so they carried out further tests on these compounds in isolation.

By dissolving quantities of the compounds in carbonated water, they were able to test each compound individually. Five common compounds in carbonated beverages were tested: aspartame, benzoate, linalool, citral, and citric acid. Their results showed that increasing the levels of all of these compounds increased the heights of the fountains obtained by as much as six times when Mentos were added, and at quantities usually found dissolved in commercial carbonated drinks. The exception was citric acid, which did increase fountain height too, but which required slightly more than usually used in drinks.

The results aren’t fully explained by the previous theory relating to surface tension. This is because some of the compounds tested actually increase surface tension when they are dissolved in water. The proposed explanation for this is that the dissolved compounds may actually be affecting how the bubbles themselves behave, and it is this combined with factors relating to surface tension that influences fountain height.

Investigating further, it was found that when the substances were dissolved in water, the bubbles produced were smaller. Bubble size, it turns out, is inversely proportional to the height of the Coke geyser; the smaller the bubbles, the greater the height achieved. The dissolved substances in the drink were stopping the smaller bubbles combining into bigger bubbles. When the bubbles are smaller, there is a greater surface area for the carbon dioxide still dissolved in the solution to escape into, so the degassing of the carbonated drink happens faster – giving a higher fountain.

Of course, the different substances dissolved in carbonated drinks don’t act in isolation, and they may also interact with one another to increase or decrease the height of the coke fountain. This may be the focus for further experiments. For now, it’s clear that there’s still plenty to learn about the best way to make the biggest Coke and Mentos fountain!

This graphic is based on the following paper:  New demonstrations and new insights on the mechanism of the Candy-Cola soda geyser   – T S Kuntzleman, L S Davenport, V I Cothran, J T Kuntzleman, D J Campbell; J Chem Educ; Link :  http://dx.doi.org/10.1021/acs.jchemed.6b00862

This is a commissioned Chemunicate graphic. Chemunicate creates commissioned graphics for chemistry researchers and institutions. If you’re interested in having a graphic made based on your research or some other topic, find out more here .

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John Kelley

really cool seeing a systematic experiment on this. I wonder how a nitrogenated beverage would compare, since nitrogen bubbles are inherently smaller? (Guinness was my inspiration on this thought :] )

also made me think of another experiment designed for guys doing dumb things: take a mouthful of soda and drop in a Mentos. How many Mentos can you drop in while being able to keep the soda from spewing out of your mouth (i.e., how strong is your mouth vs the pressure released)? (kids, this is rhetorical – do not actually try this)

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Mentos and Coke Experiment: How-To Plus Free Worksheet

This explosive experiment teaches kids about physical reactions.

Adding Mentos candy to Coke is the stuff of legend. Every kid has heard the rumors about the explosive combination that results, but how many have actually tried it? While science teachers have been performing this experiment for years, it was first popularized in September of 2005 thanks to a viral video from Steve Spangler Science . The several-foot-high geyser that shoots from the soda bottle is a fun and awe-inspiring hands-on activity that any scientist in the making can perform. Be forewarned though: You’ll probably want to perform this experiment outside.

Read on to learn more about the Mentos and Coke experiment, and fill out the form on this page to grab your free recording sheet for the experiment.

How does the Mentos and Coke experiment work?

In this experiment, you drop Mentos mints into a 2-liter bottle of Coke. Make sure your bottle of soda is on a flat surface in a location where it is OK to make a mess. You then load the Mentos into your paper roll or geyser tube . Once the Mentos are dropped into the soda, they sink to the bottom, which causes the gas to expand and pushes the soda out of the bottle. This creates an exploding geyser effect.

What does the Mentos and Coke experiment teach?

Although you can’t see it, dissolved carbon dioxide is the invisible substance that makes soda bubbly and fizzy. As long as the soda remains in the bottle, the gas is kept in place through the pressurized conditions. When you shake a bottle of soda, some of that gas is released and the bubbles stick to nucleation sites or tiny defects on the inside of the container. If you open the shaken bottle, the bubbles will rapidly rise and push the liquid up and out of the bottle.

Aside from shaking the soda, another way to help the carbon dioxide escape is to drop an object into the bottle. Mentos are the perfect objects, since each candy has many little pits on its surface that serve as nucleation sites. Once the Mentos are dropped into the soda, the bubbles stick to those sites and quickly rise to the surface. The weight of the Mentos drives them to the bottom of the bottle. Then, the gas that is released by the Mentos forces the soda to shoot out of the bottle in a powerful geyser.

Is there a Mentos and Coke video?

This video shows how to do the Mentos and Coke experiment using just a few simple ingredients and supplies.

Materials Needed

To do the Mentos and Coke experiment, you will need:

• A roll or box of mint-flavored Mentos
• 2-liter bottle of Coca-Cola (aka Coke)
• Sheet of paper to roll into a tube OR pre-made geyser tube

Our free recording sheet is also helpful—fill out the form on this page to get it.

Mentos and Coke Experiment Steps

1. make a paper tube by taking a piece of paper and wrapping it around a roll of mentos, then taping it in place. pull the mentos out. alternatively, you can use a premade geyser tube available from amazon or other retailers..

2. If using a geyser tube, load the Mentos. If using a homemade paper roll, drop the Mentos into the roll while holding the bottom closed with your finger.

3. Placing a 2-liter bottle of Coke on a flat surface, remove the cap, and drop the Mentos into the open Coke bottle.

Grab our free Mentos and Coke experiment worksheet!

Fill out the form on this page to get your worksheet. The worksheet asks kids to guess the correct order of the steps in the experiment. Next, kids must make a prediction about what they think will happen. They can use the provided spaces to draw what happens before and after they add the Mentos. Did their predictions come true?

Additional Reflection Questions

• What happened when we added the Mentos to the Coke?
• What difference do you think the temperature of the Coke makes?
• What do you think would happen if we used different-flavored Mentos, like fruit?
• What do you think would happen if we used a different soda other than Coke?
• What do you think would happen if you use Diet Coke?

Can the Mentos and Coke experiment be used for a science fair?

Yes! If you want to do the Mentos and Coke experiment for a science fair, we recommend switching up some of the variables. For example: Does the temperature of the Coke matter? Does the brand of soda matter? Will generic soda produce the same results as the brand-name soda? What happens if you use fruit-flavored Mentos? What happens if you use Diet Coke instead of regular? Form a hypothesis about how changing the variables will impact the experiment. Good luck!

Looking for more experiment ideas? Check out our  big list of experiment ideas here.

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