Mentos Geyser Hits the Classroom… But Some Teachers Don’t Get It

It has the potential of being the most popular science fair project of all time. The Mentos Geyser is definitely fun to watch, but some teachers are missing the opportunity to use the activity to teach science. Over the last few weeks, I’ve received emails from students explaining that their teachers are forbidding them from doing the Mentos Geyser as a science project. Why? The common response is… “there’s no science to blowing up pop.”

What? How did these teachers miss the rich science content that oozes from the bottle with every eruption? Combine the strong science with the student’s motivation to want to use the scientific method and you’ve got an amazing activity.

Brian Rice, a math teacher at Gwinn Middle School in Michigan, recently used the Mentos Geyser as a great teaching opportunity. As one of the experiments, the middle schoolers measured how high pop would spray when a Mentos candy is dropped into the pop bottle. In one day, eighth-grade classes and some seventh-grade classes conducted the Mentos and pop experiment with the objective to see whether different types of pops have greater eruptions. They ended up testing a total of 44 different varieties, ranging from Diet Coke to root beer.

This is a great example of science in action. Here’s to Brian Rice – a great teacher who gets it! Instead of forbidding the activity, Mr. Rice uses the Internet sensation to grab his students’ attention and put the scientific method to the test.

20 replies
  1. ayon
    ayon says:

    Steve can you tell me an interesting 5th grade experiment thaat my friends and i can do? Oh by the way your blog is pretty cool.

  2. shana curtis
    shana curtis says:

    I wanted to thank you for your website as a homeschooler of 4 children your website has proved to be very valuable. I plan on doing this mentos experiement the minute we get a warm day, i have also bought a video that explains why the reaction between the mentos and soda is so explosive, i think this will be a wonderful learning lesson and i am looking forward to doing it. Thank you for the wonderful experiment ideas.

  3. Brian Priesman
    Brian Priesman says:

    I would love to know what video Shana Curtis bought. I was unner the impression that no one has been able to prove WHY the experiment works. I know there are lots of theorys, from the Cocunut Oil and Gum Arabic to the who knows what else… I keep telling students in my workshops and demos that, if they really want to become rich and famous, they need to work on figuring out why this works…

  4. Steve
    Steve says:

    I think that Shana Curtis is referring to the videos from our show on the NBC affiliate KUSA 9NEWS. It’s well established that this is a physical reaction and not a chemical reaction. There is no evidence that the gum arabic or coconut oil has anything do to with the reaction. For a full explanation, check out this link:


    You’ll also find a great discussion thread on this blog at the address below:


  5. Rhina Briceno
    Rhina Briceno says:

    I’m a teacher in Honduras Central America and I would like to thank you for the experiment of the torando in a bottle. My students were amazed and excited to do it.

  6. JoAnna Nichols
    JoAnna Nichols says:

    Hey Steve,

    I use the Mentos Geyser to show propulsion. Following the demonstration, I ask the kids if we could have gotten the Mentos into the bottle and turned the bottle upside down, what direction would the bottle go. (They always answer UP!), I explain that is how rockets work, to push the “fuel” into a small area. (If I’m wrong in doing it this way, I would love some feedback!!)



  7. Steve
    Steve says:

    JoAnna – I really like your example for propulsion. You can also show what happens if the top of the bottle has a smaller opening. Take a look at the LifeSavers Trigger Method.
    You can also do something similar with Mentos. Our new Geyser Tube toy will be available in stores in a few weeks and this will also let you change the opening on top of the bottle.

    Keep up the great work.

  8. Marilyn Jones
    Marilyn Jones says:

    I’m a student in the education field and I like to look for future experiments to do with my students. This sounds like an exciting experiment to do with students of all age.



  9. Joe
    Joe says:

    Seen at mentos.com:
    Why does dropping a Mentos into a bottle of soda create a reaction?
    The reaction occurs because of a simple rule of physics. It is not a chemical reaction. Soda drinks contain a certain amount of CO2 (carbon dioxide) dissolved in water in the form of tiny bubbles. This combination of water and CO2 molecules is in a permanent instable state. When Mentos dragées fall into this liquid, this state is disturbed. The more Mentos are dropped into the liquid the more this state is aggravated. The reason for this lies in the surface of a Mentos which looks smooth but is actually very rough! Within the nooks and crannies of the microscopic rough surface, bubbles form, which are in turn transformed into foam, which can lead to very impressive foam fountains. (See: http://www.eepybird.com)

  10. Anna Williams
    Anna Williams says:

    I am doing a college project where we have to build a vehicle (car, rocket,…)whose sole propulsion comes from coke and mentos. last years winners vehicle went several hundred feet and of course, our team is looking to beat the record. Any suggestions? we cannot use batteries, solar panels,….etc. to help propel it, only the coke and mentos. We are trying to work out a hovercraft but are having trouble with the weight load. anything ideas will help.

  11. Julie Gintzler
    Julie Gintzler says:

    The most basic concept you want to keep in mind is that you want to make the hole where the soda will exit as constricted as possible. If you take a look at the geyser tube toy (https://www.stevespanglerscience.com/product/2072) you will see that the main reason the geyser goes 30 feet in the air is because the hole at the top is so much smaller on the toy than on the standard opening of a pop bottle. As for your hover craft idea, I would suggest finding a material that will not break the surface tension of the soda as it exits the bottle. One more thing to keep in mind is that warm soda will create a much higher geyser than cold soda. Good Luck with your project and please share your invention with us when you finish. I can’t wait to see how it turns out!

  12. Danielle=)
    Danielle=) says:

    Hello Steve! Your website is very nice! I have a question for you to ask and I hope I get the answer A.S.A.P!
    I am in 5th grade.
    My school is doing a science project.
    And I, obioviously, have chosen this topic.
    My question was ( for the science project.)
    “Which brand of mints will make the soda explode higher, Mentos or _______.
    I am still working on that last word.
    Do you know if there is a brand of mints that will make the soda explode? ( at least a little bit?)
    If not can you also tell me what other possible question that I could do? Ect. How high does the mentos “mint flavor explode? (By average)
    I dont know a-lot though because I am in 5th grade.
    That question i told you for an exsample might even work.
    I don’t know
    I hope you can help me with all the Questions,
    Though I find them very,very hard.

    Waiting,and hoping for an answer,

    • Susan Wells
      Susan Wells says:

      Hi Danielle – First, I want you to know that I am positive you know a lot, BECAUSE you are in 5th grade. Don’t sell yourself short. You have a great start with your question. The best part about this project, is you get to go out and try and find the answers. Science is all about testing and finding the answer. Start in the candy aisle at the grocery store and pick a few different candies that YOU think may work. Pick them based on what you already know – something that will fit into the soda bottle, something that has a lot of surface area like Mentos. There isn’t a wrong answer. To save a little money, pick a few candies and one bottle of soda. Pour some soda into a cup and drop one candy in. Watch for any reaction. Then, test the best one or two against the Mentos with full bottles of soda. I don’t want to give you all of the answers, but I will give you a hint – before Mentos, teachers used Wintergreen Lifesavers to do the erupting soda experiment. Good luck!


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