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Fizzy science 2 – Coke and Mentos

IMG_2139Last weekend we decided to go back with the girls and continue our fizzy experiments. We bought the wrong kind of Mentos last time and never got the geyser that we were expecting (specifically: the fountains of the Bellagio with Coke and Mentos). Chewing gum Mentos did not do the trick. This time we decided to take a different approach and see if different types of Coke and Mentos had different reactions. We got 2 liter containers of Diet Coke, 3 20 oz. containers of Regular Coke, Coke zero and Diet coke, then we got a smaller version of the Diet coke. And we also bought mint and fruity Mentos.

Coke-Mentos-ExperimentsThe first part of our experiment was to see what would happen by just dropping one mint Mento in the same amount of Diet Coke,  Coke Zero and regular Coke. These were the results:

Coke and Mentos 13-types-Coke-MentosThe most reactive was Coke Zero, but Regular Coke took the longest to stop fizzing.

Next we dropped 4 mint Mentos into 20 oz. bottles of the Coke Zero, Diet Coke and regular Coke. This is what happened:

Coke Zero

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Diet Coke

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Regular Coke

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You can see on the last picture that the girls were very curious about the SMELL of the reaction… even though there really wasn’t one.

The one quantifiable result we did measure was that the amount of liquid remaining in the bottles after the Mento reaction was different, making Coke Zero our frontrunner; unfortunately we only bought one bottle. This is how much was left of each:


Next we tried with a smaller bottle of Diet Coke and 4 fruit Mentos. This is what happened:

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The next experiment was with a 2 liter bottle of Diet Coke and 12 Mint Mentos. This was the result:

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The geyser shot about 6 feet up. The reaction was so big I couldn’t get the top part of the geyser on camera… I wasn’t fast enough!

At this point, Little Miss I and Little Miss Z were not interested in our geysers anymore… so they left for a while and played something else in the concrete covered patio… 

We got their attention back when we rescued the spent Mentos from the bottles, and asked what would happen with the used Mentos (fruit and mint combined) if used in a fresh bottle of Diet Coke.


We got this:

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Finally we tried with a combination of used Mentos and 6 fresh Mint Mentos in 2 lt. of Diet Coke — the girls were very curious to see how tall the geyser would go. Here’s what they saw:

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Once we were out of Coke and Mentos, we wanted to try again with vinegar and baking soda, using the 2 lt. Coke container, as well as the “Mento launcher.”

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The geyser was very small, but the reaction kept going, making the bubbling last a lot longer than with the Coke-Mento blast.

Without a doubt, the funniest things about the experiments of this day was the obsession with the smell… as well as at some point even trying its taste (yuck!!) We think next time we’ll make an experiment that addresses the sense of smell and taste, to cater to their curiosities. Maybe fizzy bath bombs? Or how smell and taste work together? We’ll see… Stay tuned!

About Erika

Worked in film and TV for several years before having my two wonderful children. Now I try to bring that creative input into my home to raise my kids. Hope you enjoy following this journey!
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  1. We love this experiment! My little guy did it when we were homeschooling…and then every time we went to the store after, I’d find Mentos in my cart for the longest time! LOL Love your pictures!

    • Thanks, Donna! Taking the pictures was fun, and there are some really pretty ones of the foamy geysers! We’ll keep doing these science experiments and posting them, so keep visiting!

  2. How fun! Great photos too!

  3. So much fun!! My 8 year old loves this experiment, but I’m not sure my 4 year old has seen it… I know what we’re doing this weekend!! 😉

  4. Hi! I can’t see the pictures for some reason, the ones showing the levels of the small bottles won’t load. Tried on the computer and my phone. Did the small bottles work ok? My son’s birthday is coming up but I can’t afford 2 liters for everyone. Thank you!!

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