A Soda Science Experiment

I’ve always loved science, and both of my girls love doing science experiments. Fortunately, my mother-in-law is a former science teacher and always has really fun and interesting experiments for the kids to do when we have visits (well…dissecting the owl pellets was interesting for sure…but I don’t know if I’d call it fun because it was kind of gross).

Diet soda + certain candy = BOOM!

We just had a really fun family picnic where my mother-in-law decided to have the kids do an experiment involving diet cola and Mentos candy that she saw on Steve Spangler’s website (that site has AWESOME simple science experiments for kids of all ages). Note: this has to be done outdoors in a big, open space! Anyway, you load 9 white Mentos into this “launcher” (a clear cylinder that screws onto the bottle top with a string to pull that releases the candy into the soda), have one of the kids pull the string and…BOOM! It kind of explodes. 


Well the bottle itself doesn’t explode, but the soda shoots out of the top like a geyser.  Check it out in this video:

It shot up more than 20 feet into the air when we did the experiment at the family picnic!

This experiment brought me back to the days of my youth where people used to warn kids not to drink soda after eating Pop Rocks because you’d make your stomach explode or something like that. While we laughed it off as an urban myth, my siblings and I never risked that. Now after seeing the soda/Mentos geyser effect, I’m glad I never took that risk!

More recently, I learned about another chemical reaction that happens with candy and potassium chlorate. Apparently if you mix gummy bears and potassium chlorate (used as a disinfectant, explosive, oxidizing agent, and fertilizer), you get multiple explosions.

What’s this doing to people’s stomachs?

While these are great science experiments that delight both kids and grown-ups, it does make me even more concerned about what these substances are doing to our bodies when we ingest them. Of course the Pop Rocks/soda thing tells us it can cause serious, if not fatal digestive damage…but what about the other candies and sodas that people often consume together and in large quantities? What if you happen to be at the movies, and decide to get a large cola and theater-sized box of Mentos—are you going to be the cause of the special effects at the movie because you ate a handful of the candy and then took too big of a swig of soda to wash it down?

Please don't spoil the movie by adding your own special effects.

Of course Coca Cola didn’t really express any concern about this—not that I would ever expect them to—they simply said rather matter-of-factly that they “would hope people want to drink (Diet Coke) more than try experiments with it.” Um…NO THANK YOU.  The horrible health issues associated with drinking soda were enough to keep me away from it, but now after seeing this happen I could not even imagine putting this into my body. It was also a great way to teach my kids to not drink soda—I simply said “you see that? Now imagine what that can do inside your stomach.”

Many people I encounter who suffer from digestive issues (agita), acid reflux, IBS, and constant gas drink soda regularly. When they reduce or quit drinking it, they miraculously start to feel better—and they usually lose weight and have other noticeable improvements in their health. Now after seeing this experiment I can’t help but think it was no wonder I had agita for so many years. I never had it as a kid (my mom was very strict about soda)—I only developed issues when I started drinking soda as a college student. Once I stopped for good, the agita was gone for good.

How does this happen?

There is a lengthy scientific explanation of how this phenomenon occurs when you mix these particular candies with diet cola. You can read that here, but in short, it has something to do with the rough surface of the coating of the candy creating more surface area for bubbles to form when the gum arabic and gelatin in the candy coating mix with the aspartame (NutraSweet), potassium benzoate, and caffeine in the soda.

So one might think the message here is to not mix Mentos and diet soda and you’ll be fine, right? I’m not so sure. Gum Arabic, caffeine, gelatin, aspartame, potassium benzoate, and many other chemical compounds are found in the majority of candies and sodas on the market, as well as many packaged and processed foods. While not all of them might have the correct surface tension/surface area ratio for a large-scale chemical reaction to occur, I would still be concerned with having that mix of chemicals in my stomach at once—especially when you factor in certain enzymes and acids already present in the body.

So all this is yet another way of recommending that people significantly reduce or eliminate their consumption of soda, candy, and other processed and packaged foods. You don’t see these types of science experiments with whole foods!

The moral of the story: if it explodes in a science experiment, don’t eat it! Even if it is considered by some to be a “food.”