Does Diet Coke Really Produce the Best Results?

Believe it or not, research scientists have actually concluded that Diet Coke produces the best stream of flying soda (much to the joy of the Mentos Experiment enthusiasts). I received an email from Dr. Joe Maglaty, Director of Education Outreach from the Merck Institute for Science Education with this information:

I recently came across an article that you may, or may not, be aware of. In the April issue of the Journal of Chemical Education, a chemistry professor from Illinois State Univ. took on the analytical process for showing gas solubility in aqueous solution – that is, how much carbon dioxide (CO2) is released from soda (pop) using ultrasonic energy. Since ultrasonic waves provide millions of nucleation sites at the wave nodes inside the soda bottle, this technique is much more effective in releasing CO2 than any physical substance, such as Mentos or Lifesavers. The quantitative results are quite impressive, with the bottom line being that Diet Coke at room temperature is the best way to eject most of the soda into a fountain.

The Journal of Chemical Education article probably gives you more information that you’d ever want on the topic. A PDF of the full text is also at this location. With this phenomena of releasing carbon dioxide quickly from a gas/liquid mixture, more teachers should take advantage of this opportunity to explore this science with their students. Everyone should share in this excitement and be involved with inquiry based, hands-on and minds-on science activities that helps us understand and learn from the world around us.

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Comments (28)

  • Daray Reply

    I am a Pre-K teacher putting on a Science camp in Texas this week. Let me assure you, clear diet drinks only produce a gurgling stream of about 3-4″. I was so disappointed not to have the 8″ shoot I was expecting. It was a real let down for the kids. I promised them we would try it again in two days with diet COKE this time. I used the clear soda hoping it would not stain their clothes when it sprayed out … my bad for not tryng the experiment ahead of time with the clear soda!

    June 21, 2006 at 2:08 pm
  • Margaret Newsom Reply

    I taught a science camp for 3 & 4 year olds in Houston and we tried pretty much every soda out there over the course of a week…it became a daily ritual. We concluded that diet Coke does indeed soar the higest (one student wanted to know if that’s what makes rockets go…). Diet Sprite came in second, with orange soda performing at the lowest height – only about two feet. We tried funneling the Mentos in, using a test tube, and on string – the test tube worked the best for us.

    We had a lot of fun, but the best part was how excited the children were about these activities and how thrilled they were to move on to related activities. I teach at a school where the children come in very prepared academically, but many missing the joy of discovery and a desire to experiment with materials. Thanks for so many wonderful ideas shared here.

    June 25, 2006 at 8:24 pm
  • Amy Beaman Reply

    And it’s true! Our scientific research……outside my parent’s home on Mother’s Day with many friends, family and curious neighbors watching, proved the same thing.
    Most were betting on whether we’d be able to drop in the Mentos w/o being completely drenched! And we also found that if you don’t get all the Mentos in, that does affect the quality of the “plume”!

    Thanks Steve! Another example of if you get it to the dinner table, you’ve won!

    June 26, 2006 at 6:57 am
  • Steve Reply

    I received an email with this information…

    I have some additional information on this experiment. I’m pretty sure the reason that Diet Coke works better than regular is because the diet sodas contain more carbonation than regular sodas. I’ve worked in several fast food places, and the diet beverage syrups are always mixed with a higher carbonated water to syrup ratio than the regular sodas. For example, Coke is mixed at 5:1, and Diet Coke is mixed at 5.2:1

    Dustin Oliver

    September 14, 2006 at 9:51 pm
  • Amber♥ Reply

    Hi.Ice it really Coke or Deit coke??

    May 28, 2008 at 9:02 pm
  • JGoodwin Reply

    Hey, Amber! It’s Diet Coke, not regular Coke. the Diet Coke works best because regular cola doesn’t have as much carbonation as the diet colas have. Thanks for asking!

    May 29, 2008 at 12:17 am
  • Amanda Smith Reply

    Does it work better if the pop is room temperature or cold???

    October 7, 2008 at 7:56 am
  • Steve Spangler Reply

    Hi Amanda,

    The experiment definitely works better with room temperature soda. If you use cold soda the geyser will be much smaller. Good luck and have fun!


    October 8, 2008 at 8:47 am
  • jake rizner Reply

    hey, im doing a science fair project. I want to use three different types of diet soda and see which one shoots the highest. How can i measure this and is this a good experiment for the coke in mentos combination?

    January 8, 2009 at 8:35 am
  • Steve Reply

    Hi Jake,

    That is a great idea for a science fair experiment. Here is the link to the page where we list all of our science fair tips for the Mentos Geyser
    Hope that helps and good luck!

    January 8, 2009 at 5:44 pm
  • Cassie Reply

    hi, I am doing a science fair project. Is it better to test the temperatures of different sodas – hot, room temperature or cold or to measure the explosion or different types?

    What is the best way to measure the explosions and record them?

    March 17, 2009 at 1:53 pm
  • shay Reply

    yeah i just did this project yesterday and diet coke shoots way higher then regular coke because of the caffaine and more…but i had a blast and apparently so did the diet coke was fun i ate the extra mentos left over also ….yay you should try it yourself and see how funn it really is and you learn a lot from this experimentt.

    November 25, 2009 at 8:56 pm
  • lars Reply

    I am doing a science project, and i think adding dry ice to the mentos and diet coke combination might exceed average heights. I don’t know what would happen.

    January 21, 2010 at 9:23 pm
  • any Reply

    does the mentos work with regular coke

    January 30, 2010 at 2:33 pm
  • juliegintzler Reply

    It sure does! Just about any carbonated beverage will work to make a mentos geyser.

    January 31, 2010 at 1:52 pm
  • juliegintzler Reply

    The mentos geyser will work with any carbonated beverage. Many choose diet because it is less sticky

    February 4, 2010 at 9:51 pm
  • Steve Spangler Reply

    Works great… but it’s better with Diet. Diet Coke contains aspertame and potassium benzoate, chemicals that help bubbles form easily. However, the best reason for using any diet soda is because there’s no sugar – it’s not sticky. When we do a huge geyser demo at a conference, we’ve found that Diet Coke with Splenda shoots the highest.

    February 11, 2010 at 4:54 pm
  • juliegintzler Reply

    The mentos geyser will work with any carbonated beverage.

    February 15, 2010 at 4:55 pm
  • Julie Reply

    Does Coco Cola Have more Carbon Dioxide Then Sprite?

    November 29, 2011 at 8:50 pm
  • Julia Reply

    Does coca-cola have more carbon dioxide then sprite?

    November 29, 2011 at 9:13 pm
    • Susan Reply

      I’m not sure about that one. You should try experimenting to see if you can find the answer.

      November 30, 2011 at 11:33 am
  • Ryan Reply

    best with mint or fruit mentos? Trying to make a mentos and coke rocket. Also, I’ve already bought a bottle of regular coke. Is that still any good or should I just buy diet?

    April 5, 2012 at 11:28 am
    • Susan Wells Reply

      We’ve always used the mint Mentos due to their porous surface. Trying the fruit Mentos would be an interesting experiment. Diet Coke has the best track record, but yes, regular Coke will work too. Good luck!

      April 5, 2012 at 1:29 pm
  • noah Reply

    hi this is noah, 6th grade,will u answer question about the science fare that i have concerning to the geyser of soda. For instance:

    How do i measure how hi the soda goes and which size of soda can can i use

    January 26, 2013 at 10:42 pm
    • Susan Wells Reply

      Hi Noah – The best way to measure the height of the geyser is to place measurements on a wall. Measure every foot and mark it 1′, 2′, etc to about 6′. Then launch your geysers and watch how high they go. It’s good to work with a partner so you can launch the geysers and have someone to note the height. They go fast! As for size, you choose the size. Our favorite size is the 2 liter bottles, but you will get a great eruption with any size. Just make sure all of the sodas that you test are all the same size and you use the same amount of Mentos so you can correctly compare the height between each one. Good luck!

      January 28, 2013 at 10:02 am
  • Reyna Reply

    I found out that Diet Dr.Pepper goes higher than Diet Coke.

    November 16, 2013 at 7:14 pm
  • sheeps Reply

    Thanks everyone! your comments proved helpful for my 7th grade science fair project. Glad it is a fun easy project to do!

    April 19, 2017 at 1:39 pm

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