Kiwi Crate Crafts, Part Deux
Saturday 9: Welcome To My Nightmare

LAB: The Diet Coke And Mentos Experiment!

Intrigued by this drawing of Sophia's from last week:


and the subsequent comments after sharing it on Facebook, we decided to conduct our own such experiment.


But first, we picked up Victoria and went to the beach at nearby Biscayne National Park - free for military members and retirees! The kids had a great time, and we saw lots of fishes. Sophie swore up and down that there was a barracuda in the water, so I got up off my duff and ran into the water to see. Well, sure enough, there was a 2'-long narrow-bodied, slowly-hanging-'round fish, but I could not get a good enough eyeball of it to verify its cuda-ness. 

Also, I had asked Chlo to take a bath the night before we went, but Sophia reminded her that not bathing would grant her a chance at a remora cleaning. Our first time there, 18 months ago, a remora came over and cleaned me. No such luck this time, but she did take that bath, so... Anyway.


On the way home from Remora Beach (our nickname for the park), we picked up some Dominos Pizza and headed home for lunch. When everyone was done, I set up the lab: I had two different kinds of Mentos, "Mint," with a blue wrapper, and Spearmint with green. I had seven different drinks, including two bottles of Diet Coke - one for each type of Mentos.

I asked the Hubs to step up and deposit the first round of blue Mint Mentos into the first bottle of Diet Coke, with the kids standing nearby wearing sunglasses for in lieu of safety goggles. He was happy to oblige.


Hee. He got about five of the eight or 10 mints I gave him into the bottle before it whooshed up into his face, giving him a thorough soaking. Fortunately, he wasn't hurt and laughed it off. The kids, whom I hadn't told anything about what to expect, were in hysterics.

I had asked them for hypotheses beforehand, and their guesses ranged from "nothing" to "the bottle will fall over" to the correct "there will be an explosion, and it will splash all over the place."


Chloe bravely stepped up to insert the Spearmint candies into the second bottle of Diet Coke, but not before I asked for a second round of hypotheses. Everyone thought that the Spearmint would produce an even stronger reaction than the Mint, but they were wrong. It was still pretty impressive, but the plain "Mint" flavor produced a stronger reaction.

{If you're going to replicate this test, I would suggest just sticking with Mint and trying the Fruit flavors as well. They're supposed to work similarly, which I was surprised to read.}


Sophie stepped up to dump the next round of blue Mint Mentos into a bottle of Sierra Mist.

Hypotheses: "No reaction" to "even stronger yet" because of the acidity in the lemon-lime soda (my interpretation of their guesses).


Results: Same reaction as the Diet Coke. Why? My four students guessed it was because of a mix of the sugar in the soda and sugar in the mints. Huh. Interesting.


Sophia, that crazy kook of a kid, ran in to the reaction to get a drink of Sierra Mist. That goose is just like her zany (we'll call it that for today, m'kay?) mother!


Jack was up next. The kids predicted that the green mentos would react in a manner identical to the blue mentos in the Sierra Mist. 

They were wrong! The reaction was much weaker. Why? They guessed it was because there was less sugar. Hmm... Onwards.


Sophia, again, ran into the explosion for a taste. That girl! She got a little scolding for that. Hey, it was ruining my shot! ;)


Finally, it was Victoria's turn to drop some blue Mentos into our next victim: a 2-L bottle of Diet Mountain Dew. (Oh, the sacrifices I'll make for their education.)

Hypotheses: "We have no idea," was the collective response to my query!


Results: There was less reaction than with the Diet Coke, but we used fewer mints. SO we decided more mints might make a stronger reaction, and I privately decided that the controls were all over the map on this "scientific experiment"! Since this was mainly for fun, and I didn't make them do a write-up on it, I cast the concern out of my head and decided to proceed.

The kids thought that maybe the lemon-lime flavors over cola flavors were a factor, but they weren't ready to put a name to the reason.


Chloe stepped up to the plate again, to drop some Spearmint Mentos into the Dr. Pepper.

Hypotheses: "It has the most sugar, so this will be the strongest reaction yet."

Results: Nope, Diet Coke was much stronger. They started to theorize that the fake sugar in the Diet Coke had something to do with the reaction. Interesting.


Seventh, we mixed Mint Mentos with full-sugar Coca-Cola. 

Hypotheses: "This will be stronger than Diet Coke, because it has more sugar."

Hm. Apparently the Dr. Pepper taught us not so much?

Results: A good strong reaction, but much, much weaker than Diet Coke with Mint Mentos. We decided fake sugar must definitely have something to do with this reaction.


Last up, Victoria stepped up to the plate to deposit some Spearmint Mentos into a bottle of Hawaiian Punch - but not before I asked for one last round of guesses.

The kids talked amongst themselves before coming to the unanimous decision that there would be NO reaction. They cast aside the sugar/fake sugar thought for a moment and decided that carbonation would be key here, and since there wasn't any, there couldn't be a reaction.


Victoria stood by as... nothing happened. Nothing at all.

They were right, by golly!

So, in the end, though we didn't look up and talk about the science behind the Mentos-and-Diet Coke reaction, the kids decided it had something to do with the kind of sugar or sugar substitute that was in the liquid, and the fact that it was carbonated. 

They're right on both counts.

But there is a bit more to it than that. You can read up on the science here, and/or watch the video with which I opened this post. 

The kids want to try again with carbonated water, with Splenda or some other sugar sub added. I think it will be interesting to see what happens.


Poor, lonely, non-reactive Hawaiian Punch

In the end, the kids had a real blast (pun maybe intended?!) and had a good time getting to know each other better, before Victoria joins us full-time on Monday. What a great way to get started!

Thanks for stopping by.


P.S. Kudos to Gus, our property manager, for stopping by after he "saw some kids playing outside during school hours." I quickly explained what we were doing, and that we were homeschoolers. He nodded, said, "Good for you. Go ahead, then," and drove away...