sand 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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Diet Coke and Mentos Soda Geyser

The Diet Coke and Mentos soda geyser, also known as the soda and candy fountain or volcano, is a physical reaction between candy and carbon dioxide that instantaneously releases the gas so it shoots into the air. There is a lot of science behind this deceptively simple project! Here are instructions for performing the original project, tips for getting the tallest eruption, options for material substitutions, and a look at how the Diet Coke and Mentos geyser works.

All you need is a packet of Mentos candies and a 2-liter bottle of Diet Coke:

Roll of Mentos candies
2-liter bottle of Diet Coke

Make sure the candy is fresh and the bottle of soda is unopened. Freshness matters!

You also need a way of delivering the candies into the soda. One method is just dropping the column from your hand, but rolling them into a paper or index card tube is more reliable. Stacking them into a test tube is another option.

Substitutions

While Mentos and Diet Coke work best, you have other options:

Any carbonated beverage
Any candy that stacks neatly into a column
Coins, shot, or other small items that fit through the bottle opening
Sand or salt instead of candy (which work quite well)

In general, diet carbonated beverages produce higher fountains than sugary ones. Also, they don’t produce a sticky mess. Uncarbonated beverages, like juice or water, do not work at all. Objects with smooth, flat surfaces (like coins) do not work nearly as well as other options.

How to Make the Diet Coke and Mentos Soda Geyser Erupt

The project is messy. You might want to step outdoors.

Open the Mentos candies and stack them into a single column.
Open the bottle of soda.
Drop the column of candy into the bottle, all at once.

If you have more candy, you can repeat the eruption using the same bottle of soda. It won’t be quite as dramatic, but still works.

Tips for Getting the Biggest Eruption

Diet Coke or other diet colas outperform any other drinks. There are a lot of potential reasons for this, mainly involving the effects of aspartame, potassium benzoate, and other ingredients on the surface tension and foaming capacity of the beverage. The worst carbonated beverages for this project are carbonated water and sparkling alcoholic drinks.
The blue Mentos candies work better than other flavors. The fruity Mentos are reportedly the worst flavor. Freshly unwrapped candies are best. Old candy is not very effective, probably because humidity changes the candy surface.
A 2-liter plastic bottle works better than any smaller bottle, whether it is plastic or glass.
You get a better eruption at high altitude or low atmospheric pressure compared with sea level or other high pressure situation.
Warm soda produces a higher fountain than cold soda.

How the Diet Coke and Mentos Experiment Works

The Diet Coke and Mentos eruption is a physical process more than a chemical reaction. The candy surface has many tiny imperfections and cavities, each only a micron or so in size. When you drop the Mentos into the soda there are numerous minute air bubbles stuck onto them. These little bubbles act as nucleation sites for rapid de-gassing of the soda:

CO 2 (aq) → CO 2 (g)

Because the nucleation sites lower the activation energy for bubble formation, you can say they catalyze the reaction.

The candies are dense enough that they sink to the bottom of the soda bottle, interacting with dissolved carbon dioxide as they fall. As carbon dioxide bubbles form, the gas is lighter than the liquid and the bubbles rise. As they rise, they expand. The pressure of the gas results in a quick release of pressure, making a geyser out of the soda. Ingredients in the partially-dissolved candy help the bubbles keep their shape and form a foam as the liquid ejects from the bottle.

Numerous investigations into why diet soda (especially cola) works better than sweetened soda or why Mentos works better than other candies answer some questions, but not all of them. The ingredients in the soda make a difference. However, which ones enhance bubble formation and which suppress it are unclear. The chemical composition of the candies likely contributes to bubble formation, but it’s really their surface structure that matters the most.

Turn the Science Project Into an Experiment

Performing the Diet Coke and Mentos project is easy, but turning the project into an experiment is also simple. Just find a variable under your control, predict the outcome from changing it, conduct an experiment that tests this hypothesis , and then analyze your results and see if your prediction was correct. Here are some ideas of variables you can explore:

Is there an optimal number of candies for the best eruption?
Compare different types of carbonated beverages. Do you think, for example, that Coke Zero performs as well as Diet Coke? Do other brands of diet cola perform as well?
Explore the effect of soda temperature on fountain formation. If you see a difference, comparing chilled and warm soda, can you explain it ?
Are there any candies that work as well as Mentos? In general, is there a way of predicting whether or not a particular kind of candy produces an eruption?
What effect do you expect, if you add a bit of bubble solution or dishwashing liquid to the soda before adding the candy?
Design different “candy delivery” systems. What are the pros and cons of each of them?
Can you make a nozzle that reduces the diameter of the bottle? If so, what effect does this have on the height of the eruption?

Fun Facts About the Diet Coke and Mentos Project

The original soda and candy fountain project, circa 1910, used Wint-O-Green Lifesaver candies (which as also great for the “spark in the dark” triboluminescence project ). However, the company changed the candy diameter in the 1990s and it no longer fits into most bottles.
Scientists estimate the eruption releases between 2.4 and 14 million bubbles per liter of Diet Coke. Regular Coke produces a lot less bubbles.
A single Mentos candy contains 50,000 to 300,000 nucleation sites, although the reaction does not utilize every one of them.
Coffey, Tonya Shea (2008). “Diet Coke and Mentos: What is really behind this physical reaction?”. American Journal of Physics . 76 (6): 551–557. doi: 10.1119/1.2888546
Kuntzleman, Thomas S.; Imhoff, Amanda M. (2021). “How Many Bubbles Are in the Foam Produced during the Candy-Cola Soda Geyser?”. Journal of Chemical Education . 98 (12): 3915–3920. doi: 10.1021/acs.jchemed.1c01001
Kuntzleman, Thomas S.; Annis, Jezrielle; Anderson, Hazel; Kenney, Joshua B.; Doctor, Ninad (2020). “Kinetic Modeling of and Effect of Candy Additives on the Candy–Cola Soda Geyser: Experiments for Elementary School Science through Physical Chemistry”. Journal of Chemical Education . 97 (1): 283–288. doi: 10.1021/acs.jchemed.9b00796
Kuntzleman, Thomas S.; Johnson, Ryan (2020). “Probing the Mechanism of Bubble Nucleation in and the Effect of Atmospheric Pressure on the Candy–Cola Soda Geyser”. Journal of Chemical Education . 97 (4): 980–985. doi: 10.1021/acs.jchemed.9b01177