Why do diet coke and mentos do that thing?
Hey. I'm Melissa.
Jam:I'm Jam.
Melissa:And I'm a chemist.
Jam:And I'm not.
Melissa:And welcome to chemistry for your life.
Jam:The podcast helps you understand the chemistry of your everyday life. So if you're just now joining us or you've, not listened to very many episodes of our podcast, Melissa really is a chemist. She has her master's in chemistry, and she's getting her PhD, and she teaches. And I am really not a chemist, and I really don't, teach or don't have any chemistry formal training of any kind other than a few classes here or there. And so what you're what's about to unfold in front of you is a real life chemistry lesson to a person who really knows it and a person who really, really, really does not.
Melissa:Really, really, really does not. But you have learned A lot through the course of doing this podcast, actually, I think.
Jam:That's true. I kinda should probably start to adapt how I word that. So I I do have the knowledge of All the other episodes you see in our feed yeah. So I guess yeah. The emphasis on formal.
Jam:Don't have the formal training. Although I am being taught by someone who has the formal Credentials to teach me. So I don't know. You tell me, am I slowly morphing into a more Chemical person?
Melissa:You're becoming a chemist. Yeah. Well, that's true. I am a chemist. But this week, the thing I'm teaching you is something I also learned about.
Jam:Oh, nice.
Melissa:So one thing that we talk about sometimes is even though I'm a chemist, that means I have studied. I've learned. I am an expert in my field, But that doesn't mean I know everything. There's still a lot that there's left for me to learn. And one of the big things that I learned is how to know what sources are legitimate and whatnot And how to think through solving a chemistry problem with all the basics of chemistry that I have.
Jam:Yeah.
Melissa:So that's a big part of what it means to be an expert. It doesn't mean that I'm always right. It doesn't mean that I never make mistakes. It means that I have studied extensively, and I'm using that information to make my best guess or to communicate to you guys. And that's what I did this week.
Melissa:Nice. So are you excited to hear the topic for this week?
Jam:Yes. More than anything in the world, please tell me.
Melissa:This is from a listener. She messaged us on Instagram. She's a listener and real life friend, Katie Jay.
Jam:Real life friend, not just to somebody, But to you.
Melissa:To me. Real life friend to me. Yeah. Katie Jay. And she said, Why does Coke and Mentos do that thing?
Melissa:Which is such a great question. I've just thought she said that thing, and it's like everyone knows what that thing is.
Jam:So True that. And, also, it is much easier to say than try to describe it. Like, what do you even say? It's like, yeah, it foams, but a lot and kind of explodes. I mean, it's like
Melissa:Yeah. Makes a geyser. Yeah. It's way easier just to say that thing. Yeah.
Melissa:I think it's so funny that she said that. So why does Coke and Mentos do that thing? And if you don't know the thing that we're talking about, stop right now. Mhmm. Go buy a 2 liter of Diet Coke, a tuba Mintos.
Melissa:Quickly dump the tuba Mintos Into the 2 liter and step back.
Jam:And do it outside, please. Your
Melissa:outside.
Jam:Your parents or housemates or whoever, spouse will Love you for doing it outside instead.
Melissa:Or if you're really worried, just watch a video. But it's more fun to do it in person.
Jam:Truly is. It really is a lot of fun to do.
Melissa:Mhmm. Okay. So I had never looked into this before, and I honestly thought it was going to be a pH question, which is acid and base. Oh. So I thought soda's kind of acidic and then maybe Mentos are basic.
Melissa:And so it's a very violent reaction with a few other factors is what I assumed.
Jam:Mhmm.
Melissa:We saw another acid base reaction for what's the difference between baking soda and baking powder? That's what makes cake bubbly and light. So I thought it was gonna be the same thing because it releases all these bubbles.
Jam:Oh, yeah. Yeah. Yeah. Gotcha.
Melissa:Well, it's not.
Jam:Oh, really?
Melissa:It isn't an acid based reaction at all.
Jam:Interesting.
Melissa:In fact, It's not even really a reaction in the traditional sense that we're used to at all.
Jam:Okay. Well, now that you don't know anything about anything anymore.
Melissa:Now that you don't know anything, it's what we would call maybe a physical change. So all of the ingredients are there, and there's no molecular rearrangement. There's no, like, new bonds forming or old bonds breaking. It's just a basically, all of the bubbles that were already there are forming super fast and escaping.
Jam:Oh, I see what you're saying.
Melissa:All the ingredients are there. Alright.
Jam:Yeah. It's just kind of changing the timetable of things In a
Melissa:way speeding
Jam:it up, whatever?
Melissa:Yes. So all this has to do with physics or in chemistry, we call This surface chemistry is the interface between liquid and gas. So this is more of a physical, quote, reaction. It's more of a physical event taking place than a chemical one.
Jam:Got it. In this case wait.
Melissa:Would it be, like, a Physical change happening. Would you spell physical f I z z? And, it's a physical change. I can never see those coming. I was like, man, I gotta
Jam:hold onto this and find put it at a good time because she's telling me important stuff. I don't
Melissa:know how you make those connections, but it's very. Your puns are always very good.
Jam:Well, I have a lot of time on hand on my hands just doing the listening part. You're doing the teaching part, so We've got time to think of jokes.
Melissa:That's true. So the basics of this is about bubbles. Bubbles, in general, it can be hard for them to form. They're made up of individual, in this case, carbon dioxide molecules. There's carbon dioxide in the solution In your soda.
Melissa:And the way a bubble forms is it has to fight against all the intermolecular forces of water that we've talked about are really strong. So water is holding on to itself pretty strongly, and then there's, you know, 1 molecule of carbon dioxide that's trying to work and get to other molecules of Carbon dioxide. And those will come together and form a bubble.
Jam:If you
Melissa:can get enough of those carbon dioxide molecules together.
Jam:Got it.
Melissa:So then when all those molecules do find each other and they form a bubble, Eventually, they can escape because they become so buoyant that they are light enough to overcome the strength of the intermolecular forces. So its buoyancy basically Beats down the intermolecular forces, and it allows it to rise up.
Jam:Weird.
Melissa:But usually to make that happen, there needs to be a nucleation site. We've talked about nucleation sites a lot. Yeah. It's a place where a crystal can start forming. Or in this case, it's something that can kinda break up the bonds between the water molecules and themselves, between all the different molecules of the water, and allow the carbon dioxide molecules to break through and find one another
Jam:k.
Melissa:And form a bubble at that nucleation site.
Jam:Okay.
Melissa:Does that make sense?
Jam:Yeah. I think so. I mean, especially because you see, like was it would it count, like, When you see the bubbles forming on the sides of the, bottle or whatever? Like, is
Melissa:that part
Jam:of why they're doing that as well? Like, Mhmm. The nucleation that that is already there?
Melissa:Yes.
Jam:Got it.
Melissa:Or if you put a straw in, that kinda breaks it up. And so bubbles can form along straws. You can see that a lot. You have, like, a clear straw and a clear glass.
Jam:Yeah. Yeah. Yeah.
Melissa:So that's the basics of how bubbles form. You just learned about how bubbles form.
Jam:Nice.
Melissa:Bubble science.
Jam:Are there bubble scientists?
Melissa:I'm sure. What we've learned in this podcast is that there's a scientist for everything.
Jam:Yeah. Yeah. Exactly.
Melissa:So in the case of dropping Mentos into a soda, what happens is that process is pushed into super speed Because there are so many nucleation sites on the Mentos candy.
Jam:Oh.
Melissa:The way we see it, it looks really smooth, but I found 1 paper where it zoomed in and you could see the ridges at a microscopic level.
Jam:Weird.
Melissa:Mhmm. And the act of it dropping through the soda is breaking up those intermolecular forces of between the water and allowing those gas bubbles to move more easily. So it's not only that there's nucleation sites on the Mentos, but it's Dropping, breaking those intermolecular forces.
Jam:Wow.
Melissa:So that's kind of the basics, but I have some more stuff that we can talk about. So do you wanna stop back and kinda explain it back to me to make sure you're tracking with me?
Jam:Yes. Totally. It seems like enough that wanna make sure I'm getting it right, and fully understanding. So we know about we've talked some about carbon dioxide and bubbles a little bit like in baking. We've talked some about, carbonated stuff in the past also, and we've talked about inter nuclear forces.
Jam:There's a few things here that are things we've talked about. So there is already the, c o two in the liquid, in the that Coke or whatever That sorta works, but I think that Coke's, like, the strongest one for some reason.
Melissa:Well, we're gonna talk about that. Don't worry.
Jam:Oh, okay. Sweet. It's already there, and it's already Being released on its own time where the The molecules of carbon dioxide are trying to find each other and almost like like with more numbers, They're able to get to a point where they can form a bubble and kind of, like, successfully push against the the, animal, like, forces of the liquid Right. To kind of form a bubble together. Kinda like if you and your friends are, like, at a concert or something.
Jam:If you're together, you can kind of, like, bunched together and pushed to the crowd or something like that more successful than just trying to be 1 individual fighting against a whole Proud. It's not like a perfect analogy, but just the idea that with more people, you can have a stronger presence in something.
Melissa:One analogy that I have thought of is when, I think it's in Finding Nemo and all the fish decide to collectively push against the net at the Same time?
Jam:Oh, yeah.
Melissa:Is that Finding Nemo? And then they can overcome the force of whatever is pulling the net in. It's kind of like that. You get enough bubbles? You get enough
Jam:Yeah. I like that.
Melissa:Enough c o two molecules together, and it forms a big enough bubble that it can Rise up due to its buoyancy.
Jam:Yeah. It can form a bubble in the 1st place and then get to a point where it rises up and can be released.
Melissa:That's right.
Jam:Interesting. Okay. So that's what it's doing. It's trying to get its friends together. Come.
Jam:We can do this, guys. We we can fight this oppressive liquid that we're all trapped in. So they're trying to overcome that and be released all the time anyway. And what helps to be able to do that is having a gathering place or a nucleation site.
Melissa:A gathering place. That's a good way to put it.
Jam:Hey, everybody. Let's go meet at the pier or whatever. Mhmm. Everybody knows where the pier is, obviously. Makes it way easier to get everybody together instead of just wandering around Hoping you'll find other people.
Jam:There's gotta be like a funnier it's like, hey, everybody. Let's meet at the soda parlor, and then we'll go, You know, paint the town red. So just like with crystals and some other reactions we've talked about, having a nucleation site like that Let's either some reaction begin or, in this case, more molecules kinda find each other and Linked together or something? Or
Melissa:Yeah. They collect together, and the reason they're able to join together is because the intermolecular force Between water is broken up usually at that nucleation site.
Jam:Yeah. Yeah.
Melissa:It's already in full mouth. There's lots of water molecules holding hands, and then something pokes out and breaks them up A little bit.
Jam:Right.
Melissa:And so they just can't form as well in that area, so then the c o two molecules can come together in that area.
Jam:Got it. Got it. Or, like, on the inside of a straw or glass or something. It's Right. It's something about the surface of that thing that's Not the water.
Jam:That's not the other liquid. It allows them to to kinda break through that surface tension Mhmm. In a relative air force stuff. Okay. So that's already happening all the time
Melissa:Yes.
Jam:In the average soda. And then You drop a Minto. What's the singular? Memento and
Melissa:I don't know. I would think it'd be Mentos. You drop 1 mint because it's like the candy is Mentos.
Jam:You dropped the mentee.
Melissa:Reese's.
Jam:Oh, yeah? Well, Reese's, what's weird about that is it's plural. Is Mentos plural? I mean, not not some plural. Reese's is possessive.
Jam:It's a family name. So I wonder if Mentos is a family name or if it's Unrelated to that.
Melissa:I have no idea.
Jam:Man, the Minto scientists need to tell us what's going on there. So You drop one of those in there, and not only is it just the act of an object entering the the liquid Gonna start disrupting some of those intermolecular forces because just kind of pushing stuff out of the way while it drops down in there.
Melissa:Right.
Jam:But, also, surprisingly, the Minto Mentos has tons of ridges and sphincter all over it that We don't really see, but on the microscopic level are significant enough to where it's just like a bunch of Gathering places all on 1 Minto. A bunch of soda parlors all on one little thing being
Melissa:Mhmm.
Jam:Being plunged into there. And so All these c o twos can get together really fast, which would have taken them, like, maybe an hour or so to all find each other and Form a bubble and get released. But now they can find each other really fast, and then all go crazy, make bubbles, and Paint the town red and and escape all at once.
Melissa:That's exactly right, and that's why Coke and Mentos does the thing.
Jam:Dang. That's way weird. Like
Melissa:Isn't it so weird?
Jam:I thought for sure it'd be like I mean, I just didn't have any even though maybe I should start Being able to have some better hypotheses now that I've learned more chemistry stuff, but I thought for sure it'd be like, oh, yeah. The makeup of this Thing is a chemical that reacts with this chemical that, like, either to change the pH or I just I just didn't know. I just had no idea.
Melissa:But it's I thought it was gonna be an acid and base reaction. No problem.
Jam:And there's so many bubbles that it doesn't to me, I just didn't think, oh, these are the bubbles that are already in there that could be formed and they, like, sort of come out over time, and they're just happening all at once. Like, that just never would've crossed my mind.
Melissa:I know. It really is kinda surprising that that's what's happening, but I feel like it's so cool that it's Yeah. You can almost get a visual of how many bubbles actually were in there all along that we just didn't know about kind of. Okay. So all that is really cool, I think.
Melissa:Yeah. So if you're not interested in it anymore, that can be your main takeaway, but there is more. So I found that a physicist had her class do an experiment on soda and Mentos To sort of give them an opportunity to do an experiment that didn't already have a solution. You know? It was a real research project.
Melissa:There wasn't This information wasn't already out there.
Jam:Mhmm.
Melissa:And she designed it as that, and it got way more complicated than she initially thought. And it She ended up publishing a paper on it, which I think is so
Jam:fun. Wow.
Melissa:And that's what I did most of this based off of. But they went into details. It's not as rigorous as it would be in a research lab, but it is pretty rigorous in terms of an experiment on a Classroom. Mhmm. So they went into all this detail.
Melissa:They tested if anything could cause a nucleation site, and they found that pretty much Anything would. You know? You could do a lot of stuff in there, and you would get the same kind of reaction.
Jam:Mhmm.
Melissa:But they found that Mentos worked best. And the two reasons they think is because they may have they have the nucleation sites available on them, but They also may contribute something chemically that helps break up the intermolecular forces between the water. Like, there may be a little bit
Jam:Mhmm.
Melissa:Of that going on that dissolves in it, although that would happen really quickly.
Jam:Yeah. It's, like, so instant.
Melissa:So it'd be pretty minimal, but also the density versus porosity is good. It plummets down to the bottom when you put that in there instead of gently floating down. You know? And they found something that had a a good density that would would plummet down to the bottom, plus having good nucleation sites is gonna be the most effective.
Jam:Wow.
Melissa:So you could drop some regular mints or something in there, but they kinda float slowly. You know, the ones that have the open center like a lifesaver's mitt?
Jam:Right. It's
Melissa:not gonna be effective. But they even had a graph of Which ones, you know, which ones went the best and all the different things that they tried. They tried Mentos and Mini Mentos and all these different things. It was really fun. And then they also tested why does it seem like Diet Coke works so well?
Jam:Yeah. That's what I've wondered a lot.
Melissa:So Diet Coke has artificial sweeteners like aspartame,
Jam:but
Melissa:they also have a preservative in there. And both of those things together Also break up intermolecular forces between water that is or between the soda that's already going on.
Jam:Oh.
Melissa:So the diet soda seems to be more effective because those things make it easier for those sodas to bubble anyway. What? So bubbles can form more easily with those weaker intermolecular forces, and that's why they react Stronger.
Jam:Right. And it wasn't wouldn't really seem like that to us just from, you know, drinking them or whatever because I know. We're not thinking about, this is so hard to drink. It's got so much inter like, there are horses in it, or it's got so little or whatever.
Melissa:But Right.
Jam:Interesting. It kinda just primes this the Environment for Mentos to to go crazy in there.
Melissa:I know. Isn't it crazy?
Jam:Yeah. Seriously. Weird.
Melissa:So that's everything. That's what I have for you to learn today. It's that Diet Coke in Mentos is just, Not even a real reaction. It's just a rapid release of gas bubbles that were already present in the soda.
Jam:Wow.
Melissa:Isn't that crazy?
Jam:Dang, dude. That's crazy. That's a serious curveball.
Melissa:And this is serious curveball. It's not what I expected at all.
Jam:Already a cool reaction. So, like, almost any explanation was gonna be cool, but this was definitely cooler than I expected.
Melissa:And It's fun that that physicist went so in-depth and learned all this stuff and tested all these things.
Jam:Yeah. That is fun.
Melissa:You can tell it was a scientist doing it, and she's like, We're gonna really dig in here. Yeah.
Jam:I've seen so many videos. Sometimes I'll just get, like, really crave this kinda thing. So many videos where people Just try to scale up experiments like this, like, to the crazy degree. So they're not scientists. They're just people who are, like, curious.
Melissa:Mhmm.
Jam:And so they get, you know, a huge bottle that they can find that still has, like, the a kind of bodily shape to it, then they create a little thing so they can put a lot of Mentos in and then pull a, like, platform out so they all fall in at once. And I not, maybe 2 or 3 weeks ago, went and watched one of those crazy videos just just for fun. I was like
Melissa:How funny that that happened to coincide.
Jam:Yeah. Really. It's like, I just really wanted to see something, like, erupt in a pretty harmless way. I don't know.
Melissa:That's all I have for you in terms of chemistry for this week. But is there something fun that happened in your week that you wanna tell me about?
Jam:Yeah. I'm I'm kinda Gonna double dip on talking about him and I celebrating our 5th anniversary. He kinda, like, nailed it, overdid it on the anniversary gift. We Don't have parameters about gifts like that. Part of the reason why is because our anniversary is super close to Em's birthday.
Jam:And so we typically don't really try to get stuff for each other for our anniversary. It's more like emphasis on spending time together, fancy dinner, some sort of really important quality time that we give. But this year, in a room
Melissa:That's sweet.
Jam:More fun than stuff. You know?
Melissa:Yeah. People are are better than Steph for sure.
Jam:In a rule breaking move, this year, Em got me a new coffee kettle, Which I think, like, partly just because I'd been complaining about my other one a lot more and kept, like, deliberating me, like, oh, should I create that part of my coffee thing next. We should upgrade this other part. And I, like, well, you know, subject her to all these rants about, like, what I should do next coffee wise and stuff. And so I didn't think about it, but I was like, oh, yeah. She's had to listen to a lot of that.
Jam:And so she, very, very sweetly got me a new Coffee kettle, which is awesome. It works a lot better than my other one, which I had for, like, 5 years. So it was it was working. I mean, it was it was Dependable for a long time. It put its time in.
Jam:So it's good to have a new one that's kinda more updated and and, just a little bit more reliable. So For some people, that might seem pretty boring. But for me, it was, like, every day when I make coffee about 4 times a day, I'm like, oh, man. This is awesome. So
Melissa:That's sweet. What a good story. Way to go, Emily. Way to break rules and get Some GIF.
Jam:Yeah. She yeah. She's like, you can't rules can't hold me down. Sorry. I don't care about your rules.
Melissa:She's a quiet rule breaker, though. You know? It's, like, never expected. She's not like Yeah. Yeah.
Melissa:You know? Did you have
Jam:a lot
Melissa:of ranting and raving about rules?
Jam:Totally. She's able to come across pretty innocently. It's like, oh, I just wanted to get you something. It's like, I can't be mad about that, but you did break the rule. That's me.
Jam:What about you? How was your week?
Melissa:Well, my week was good, but I have recently discovered Something that is life changing to me.
Jam:What's that?
Melissa:It's hats. Okay. Hats. And that doesn't hats. And that doesn't seem like a big deal, but I hate the sun.
Melissa:Mhmm. The sun and I don't get along. It hurts my eyes. It burns my skin. I would rather be cold than hot a 100% of the time.
Melissa:Other people wake up on rainy days and are a little bummed Yeah. And I'm Overjoyed. And when I wake up and it's sunny outside, I get the a little bummed feeling. Yeah. It's like somebody switched the wires in my programming.
Melissa:Yeah.
Jam:That's kinda weird. Although really intense sun and heat can be pretty rough. So Depending on the season, I feel like there's a lot of people that might agree with you.
Melissa:Well, my threshold, I feel like, is lower. I'm already tired of it being hot, And it's May. So Yeah. My roommate often sports a straw hat with a little black ribbon around it that's super cute. And I had been wearing a baseball cap.
Melissa:I didn't even wear those until this summer.
Jam:Mhmm.
Melissa:And I realized I could wear them with my hair braided, and It covered up my messy hair, and it protected me from the sun. And I was like, wow. This is amazing. But it really only looked good with my athletic clothes. And then I noticed this straw hat that my roommate was wearing, and I was like, I have to have one of those.
Melissa:And I saw a picture of 1 at Target. Was kinda trying to decide something and sent me a picture, and I thought about the hat that I saw for a whole week. And then I was like, okay. If I still want it this bad after a week, I'm going back and getting it. Yeah.
Melissa:And I went back, and it was there, and I got it. And I was so excited. It's such a cute hat. So I actually got a big floppy hat and then a less big straw hat that I can wear At more normal events, the big floppy hat is more like a pool beachy type hat.
Jam:Got it. Got it.
Melissa:And I absolutely love both of them. And I've Worn a hat every single day since I got these hats, and I never wanna stop wearing hats. I don't know how it took me 29 years to figure it out, but It's like cats were made for me. Yeah. I don't understand.
Jam:Well and what's in what's worth noting, if maybe you already said this, but, your skin is pretty reactive to the sun. But at the same time, all of us should be doing whatever we can to to keep our skin from, you know, just straight up UV exposure. And so
Melissa:That's so true.
Jam:So protecting your skin is cool. Hats are cool for two reasons. They look cool, and they protect your skin. That's very in. Kids.
Melissa:So in. That's so in. So I'll post a cute picture of me in one of my hats that I'm so excited about.
Jam:Sweet. That's awesome. I also like hats. I don't wear the big, short ones or whatever, but I I get the the excitement around hat. New hat or, like I don't know.
Melissa:Oh, yeah. You had your cryptozoology hat Mhmm. For to to support small businesses.
Jam:Yep. Yep. Yep. And I also had, like, a similar time, I got a hat that were just a lot more durable, for specifically, like, you know, being outside or something or going Mhmm. On a trip or something like that.
Jam:I was like, this is so nice. Like, it's so nice to have a hat I'm not gonna be worried about. Like, it's water resistant too. And I was just like, still a baseball cap, but it's like, This is great. This is fits more environments, fits more situations.
Jam:It's, like, weird to get excited about, but I totally totally get your excitement.
Melissa:Well, okay, listeners. If you guys have a hat that you love and that you're so excited about, post a picture of you wearing your Q hat and tag us in it, And we'll retweet it or add it to our story or whatever.
Jam:Absolutely.
Melissa:Because we we love hats, apparently, here at Chemistry For Your Life.
Jam:Yep. If you love hats, then you're among friends here.
Melissa:Well, thanks so much for coming to learn about why Cook and Mentos do that thing. Thanks, Katie j, for your suggestion. What a great Great idea. Great question. I loved the wording of it.
Melissa:It's perfect.
Jam:Me too.
Melissa:Thanks to all you listeners for coming and learning about how we love hats and How Cocamentos do that thing?
Jam:Mohsen and I have a lot of ideas for topics of chemistry in everyday life, but I wanna hear from you. So look around. Look around at the world, at your life. What are the things you wonder about that coco mentos? About something, you do every week or every day?
Jam:And send us your questions and ideas. You can reach us on Instagram, Facebook, email, Twitter at kem for your life. That's kem, f o r, your life to share thoughts and ideas. If you enjoy this podcast, you can subscribe on your favorite podcast app. And if you really like it, you can write our review on Apple Podcasts.
Jam:That helps us to be able to share chemistry with even more people. If and donate the cost of a cup of coffee.
Melissa:This episode of Chemistry For Your Life was created by Melissa Colini and Jam Robinson. References for this episode can be found in our show notes or on our website. Jim Robinson is our producer, and we'd like to give a special thanks to s Flint and v Garza who reviewed this
