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Ok parents. It's time to explore the chemistry of something we rely on every hour of every day: diapers. What the heck is going on inside there? How do they absorb SO much? Is it magic? Well, settle in and get ready to soak up some chemistry, let's get to the bottom of this mystery. Let's hope it doesn't get messy.
#070
Ok parents. It's time to explore the chemistry of something we rely on every hour of every day: diapers. What the heck is going on inside there? How do they absorb SO much? Is it magic? Well, settle in and get ready to soak up some chemistry, let's get to the bottom of this mystery. Let's hope it doesn't get messy.
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A podcast that helps you understand the fascinating chemistry hidden in your everyday life.
Have you ever wondered why onions make you cry? Or how soap gets your hands clean? What really is margarine, or why do trees change colors in the fall? Melissa is a chemist, and to answer these questions she started a podcast, called Chemistry for your life!
In each episode Melissa explains the chemistry behind one of life’s mysteries to Jam, who is definitely not a chemist, but she explains it in a way that is easy to understand, and totally fascinating.
If you’re someone who loves learning new things, or who wonders about the way the world works, then give us a listen.
Hey. 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 that helps you understand the chemistry of your everyday life.
Melissa:Okay, Jam. Today, I'm going to answer a question that you asked on behalf of all parents everywhere.
Jam:Yes. Yes. I'm so glad.
Melissa:Is how Do diapers work?
Jam:This is so I'm so excited about this episode. I'm so excited.
Melissa:Do you have any guesses?
Jam:I, one thing I wanna say too is that it's funny because my wife asked me this week if we've ever thought about doing an episode about that. And I was like, I don't know when, but I have formally requested this as an episode. So
Melissa:Nice.
Jam:It'll happen soon. And then it here here we are recording it. So I don't really super, super have a guess, except that I when I texted you that one time to ask you to kinda put this on the queue of episodes, I was looking into do you know of something called Orbeez?
Melissa:No.
Jam:Okay. Orbeez are like these little Tiny things that I don't know where they came from. Like, apparently, it's just kids know about them and have played with them, but, basically, they're like these little tiny water balloons, except that apparently they soak the water up.
Melissa:Okay.
Jam:And so
Melissa:Yes. I have heard of this.
Jam:Okay. So I the or it might not be, like, the technical term. It might just be the one of the brands or something. But I was reading a little bit about them, and then someone made a comparison to diapers. And so then I stopped reading immediately and texted you.
Jam:I was like
Melissa:Okay.
Jam:No need to continue reading this whenever we could just talk about it on the show instead, and I could learn it From you instead.
Melissa:Okay. Well, you spoiled a little bit of one of my fun facts, but that is not far off. Nice. Think you're gonna be surprised at this.
Jam:Okay.
Melissa:So just last week, we talked about nail polish. Mhmm. And you said you thought it was a polymer because it fits into a category polymers in your minds.
Jam:Right. Right. Right.
Melissa:Well, guess what?
Jam:Uh-oh. What?
Melissa:The way diapers absorb water is by having a polymer in them.
Jam:Woah. Okay. Interesting.
Melissa:And I figured that doesn't fit in your definition of polymer in your mind.
Jam:Yeah. Not really. It's not really
Melissa:yeah. So here's the nitty gritty. Okay?
Jam:Okay. I'm ready.
Melissa:So diapers have a polymer in them. It's in its crystalline state. It's a cross linked polymer.
Jam:Mhmm.
Melissa:And it has a lot of remember we talked about functional groups?
Jam:Mhmm. Mhmm.
Melissa:That's just a collection of atoms that has a similar arrangement of atoms. Mhmm. The same arrangement of atoms is it will be known as a functional group. Mhmm. So it has a repeating functional group off of it, this polymer, that is negatively charged.
Jam:Okay.
Melissa:So, Naturally, this polymer with its negative charge units on it will collect around, be closely organized around Sodium ions.
Jam:Okay.
Melissa:Let's talk about what an ion is. An atom is neutral.
Jam:Okay.
Melissa:And if it loses an electron, electrons are negatively charged, so what's left behind is positive charge.
Jam:Okay.
Melissa:The absence of electrons leaves you with positive. K. So these sodium ions, like the same one that would be in table salt, which is sodium chloride, are nestled almost inside of this cross link polymer web
Jam:Okay.
Melissa:Organized around the negative charge. So you've got the positive charge from the sodium hanging out nearby the negative charge from the polymer chains.
Jam:Okay.
Melissa:Okay. So that's how it is in its crystalline state. It's nicely closely packed in a nice crystalline polymer state.
Jam:Okay.
Melissa:It's almost like a powder.
Jam:Got it.
Melissa:But then Water, which is the main component in baby pee, hopefully, if you're fully hydrated, gets added Into this polymer, it will wash away almost. It dissolves the sodium ion. So the sodium ions are more free to move. They're not Holding everything freely and tightly, and then the positive charge from water, which has a partial positive charge and a partial negative charge, Almost takes the sodium's place, allowing the polymer to expand without ever breaking its bonds. So it can't fully be dissolved by the water.
Melissa:The bonds aren't broken. It's not fully solvated. So instead, it becomes this big Gel, lumpy mess.
Jam:Oh. What's up?
Melissa:It expands to hold that water without the bonds ever breaking so the water can't just be released back the way it does in a sponge.
Jam:Uh-huh.
Melissa:And that's how diapers hold on to pee.
Jam:Weird.
Melissa:Mhmm. So I try to think about a good, I guess, story for this or a good analogy.
Jam:Okay.
Melissa:And the best thing I could imagine is if your if your 2 fists are the polymer Mhmm. And you interweave your fingers together, you know, And you're holding a really tight thing in there like a pool ball. Yeah. It's hard. Mhmm.
Melissa:Your fists or if someone tries to poke them. It's not really gonna work Yeah. Because they're gonna have a hard ball in the middle of them. Mhmm. But if you put a water balloon in there instead, It's gonna be a lot more loosey goosey wiggly.
Melissa:And if it's a bigger water balloon, your Your naturally, your fist will expand to hold on to it.
Jam:Right. Right.
Melissa:And that's essentially what's happening here with the polymer. When it just has sodium ions, it can get closely packed. It's hard and tight. It doesn't have a lot of the wiggle room. And then the water comes and replaces those sodium ions.
Melissa:Your fists aren't so hard and tight. They're sort of spreading out, and they're a lot more wiggly.
Jam:And that's where the consistency
Melissa:goes from a powder Uh-huh. Since he goes from a powder
Jam:Uh-huh.
Melissa:To a gel.
Jam:Wow. Wow. Interesting. That's a helpful image to have, That analogy.
Melissa:Yeah. I think it's pretty hard to visualize the idea of polymers absorbing and bonding to new things and sort of spreading out, But you can visualize your fist, so that was the only thing I could think of that sort of did something similarly.
Jam:Yeah. Yeah. This is really weird. It is A lot weirder than I would have thought, especially trying to fit it in with What's been so far normal about polymers, the situations that we've seen them in in our everyday life, this one is very much Not the same.
Melissa:Totally different. It threw you for a loop. It's a new application in Polymers for you.
Jam:Gosh. That's crazy. Okay. Did I try to tell it back to you? I don't think I can come up with a better analogy than the fist and water blowing thing.
Melissa:Yeah. Maybe I shouldn't have stolen it from you.
Jam:Well, it's okay. I mean, I need it. I think I kinda needed it to, like, understand.
Melissa:Yeah. Definitely. Lay it on me.
Jam:Okay. Wait. Ions positive? Right?
Melissa:These are positive ions.
Jam:These are. Oh, ions aren't necessarily positive.
Melissa:No. Cations are positive. Anions are negative. Ions are just ions.
Jam:Ions is the overall word. And
Melissa:For charge.
Jam:Got it. Okay. Okay. So in the diaper, in the secret Compartment layers of the diaper in the black box that we call diaper. Mhmm.
Jam:Mhmm. There are there is this granular stuff, this powdery looking kinda stuff.
Melissa:Yep.
Jam:It's a polymer that has a sodium Ion in it.
Melissa:It has a lot of sodium ions in it.
Jam:Lots of sodium ions in it. Mhmm. Okay. And it could almost be like rather than just being all one big Net, it's like each thing could be like it's a tiny little net, that allows things to kinda come in and out of it. Like, obviously, nets have holes in them.
Melissa:Mhmm.
Jam:Whenever baby pee, which I loved how you said earlier, like, baby pee is most made of water. Feels like it's almost as if you're describing any other, like like, chemical or something. Like, Chlorine is mostly about baby pee. So baby, which on the periodic table is number A 199. It's mostly water.
Jam:And so when the Water goes and fills up The diaper starts going into the polymer and sodium ions. It dissolves the sodium ions into it Mhmm. Which basically freeze up the middle of these, all these tiny nets.
Melissa:Mhmm.
Jam:It gets in there. And what's crazy, which doesn't quite work exactly in the analogy, is that somehow when it gets into all these nets, it stays in there somehow. The Yeah. Polymer can get bigger a little bit and stay connected like a net would, and it can hold all this Water is coming in. And rather than just being like a balloon where there's, like, a free flowing liquid in there, it's like Tons of this going on at a really small scale, so it's, like, not like all these water balloons.
Jam:It's more like just now it's gel. Like a
Melissa:Yes.
Jam:Just like we'd have with something like aloe vera or whatever where it's like a really thick, like, gel kind of substance rather than being tons of These tons of, like, water balloons or something.
Melissa:Yes. Exactly. And the way it stays in there, this is different from a net, but the way Stays in there is water also has is made up of oxygen and 2 hydrogens. Mhmm. And it's not evenly distributed all around that.
Melissa:Mhmm. The oxygen pulls some more electrons towards it
Jam:Okay.
Melissa:Leaving the hydrogens slightly positive. So they fit into the same spaces that the sodium ion does with the positive part of the water molecule. So that's how it gets trapped is it basically just dissolves the sodium. Mhmm. So sodium likes to be in water.
Melissa:Mhmm. And then the water that's left will bind back to where the sodium had been bound before.
Jam:So it's bind it's binding, which is why it changes the consistency a little bit, what the end product is. Instead of just being like like a water droplet, kinda nestled in with all of these powdered grains or whatever, it changes the consistency of it because it's, what I would say, linking Up with the palmar?
Melissa:Or It's I'm not sure if it's a a technical chemical bond or if it's intermolecular forces, but there is a An attraction for sure between the water molecules and the polymer.
Jam:Got it. Got it. Okay. And, dude, this is just a it's, like, a little bit hard to wrap The head around?
Melissa:It is. Another good way you could think about it would be maybe the nets have If nets had something in them just laying if if you had a net laying on the deck of a boat and they had some stuff in there. Well, but nets don't hold water. It's it's tough. Yeah.
Melissa:Yeah. It's tough.
Jam:Dang it. Gosh, dude.
Melissa:You if you fill the net up with water balloons. There we go.
Jam:Okay. Okay.
Melissa:It would expand. Mhmm.
Jam:It
Melissa:would still be a net.
Jam:So it's
Melissa:not like the water balloons would just be everywhere. Mhmm. It expand and have a different overall feel.
Jam:Mhmm. Mhmm. Mhmm.
Melissa:But it still has that jelly Water like consistency, sort
Jam:of. Mhmm.
Melissa:But it's not as if water is just freely flying in and out of the net. Yeah. Comes into the net and gets trapped. Yeah. Maybe that's a good one.
Jam:And it likes to be there.
Melissa:And it likes to be there. Mhmm. Okay. So that is the basics Okay. Of how a diaper absorbs water.
Melissa:But I have some fun facts for you
Jam:Yes, please.
Melissa:Now that you've explained it back to me. So I forgot to mention the name of this polymer super absorbent is called sodium polyacrylate. Okay. Sodium for the sodium ions. Polyacrylate is the is the negative part of the polymer.
Jam:Okay.
Melissa:And sodium polyacrylate can absorb 300 times its weight in tap water.
Jam:Woah.
Melissa:Tap water has some other salt ions in it. Mhmm. So it has some things that are competing for those negative charges. So if you get deionized water with absolutely no Salt in it? Mhmm.
Melissa:Sodium polyacrylate can absorb 800 times its
Jam:heat my gosh.
Melissa:In water.
Jam:Dude, that is I so crazy.
Melissa:And this is part of a class of compounds known as super absorbent polymers.
Jam:Mhmm. Interesting. Gosh, dude.
Melissa:Mhmm.
Jam:Let's cut some diapers open. You know?
Melissa:Well, it's funny that you should say that because I'm thinking that is going to be Our next activity for chemistry for your life at home.
Jam:Nice.
Melissa:Yeah. What can I say? Also, this same technology is used for those absorbable toys, the ones that can grow when you put them in water. So you called them Orbeez, but I had little tiny Martian men that we would soak in water, and they would grow Several size bigger? Oh,
Jam:yeah. I think we actually had some of those 2 as kids. Like, the consistency is kinda different because Orbeez
Melissa:Right.
Jam:End up looking a lot like little water balloons, but
Melissa:Mhmm. The
Jam:oh, yeah. I didn't think about that. Mhmm. Those little dudes.
Melissa:So those are the same. But I did read an article in the journal pediatrics that those are pretty dangerous to have around kids because they can swallow the small orbeez and in your body absorb Water. Oh. And so, actually, there's a scary story of a little kid who had to have surgery because of the of the it wasn't Orbeez brand, but it was a Small marble like ball that absorbed to a much larger ball, and it had to be surgically removed.
Jam:Yikes. Dang, dude. That is Mhmm. Scary. Yikes.
Melissa:So PSA to parents out there. And it's also this technology is also used to release water into soil. That's originally how they developed These was looking into how to have something that could give water back in the soil, like soak it in, hold on to it, and then give it back. Uh-huh. Uh-huh.
Melissa:And it's used in cosmetic properties like hair gels.
Jam:Oh, interesting.
Melissa:So all over the place.
Jam:Yeah. Seriously. That's crazy.
Melissa:And that's how diapers work.
Jam:Dude, thank you. Now I know. I have changed
Melissa:Now every time.
Jam:So many diapers.
Melissa:Every time you change those diapers, you're gonna say thank you, chemistry, for absorbing all this baby pee.
Jam:I'm sure I'm sure that My kid will love hearing that every single time multiple times a day.
Melissa:Yeah. I think as a child, I'd be happy to hear that 6 or 7 times a day.
Jam:Yeah. And there's definitely times where I've been impressed at how much The diaper has held, so, like, maybe, like, his diaper he wore overnight thing. And I'm like, dude, this thing is packed with some baby.
Melissa:Yeah. And it theoretically could hold even more If the pea has a higher component of water and a lower component of salt and other things present, then it will be competing.
Jam:Right.
Melissa:So that's crazy to think about.
Jam:Dude's for real. Very impressive.
Melissa:Don't wait. Don't worry. We're gonna cut into some some diapers and do some experiments with them just as soon as we possibly can.
Jam:Okay. Sweet. Dude, I'm ready. I'm definitely interested in doing that.
Melissa:I will say too, I looked up the safety of this molecule, this polymer on a safety data sheet, so not on a bias source. Mhmm.
Jam:And
Melissa:it said it can really irritate your mucous membranes, which is anything like your eyes or your mouth that has a high water content. That makes sense because it can absorb the water. So that is gonna irritate it because it'll soak up the water. So you don't want this to come into contact with your eyes or your mouth or your nose.
Jam:Okay.
Melissa:And try not to inhale it or anything like that.
Jam:Got it.
Melissa:And it can be a mild skin irritant, but usually just soap and water wash with soap and water, if it comes into contact with skin, will take care of it if it's if it's irritated. So it is a nontoxic substance.
Jam:Interesting. Good to know.
Melissa:Yeah. So it's safe should be safe to use on babies, should be safe to use in Whatever context it's currently being used.
Jam:Got it.
Melissa:As long as you're not breathing it in or rubbing it in your eyeballs.
Jam:Got it. Got it.
Melissa:Okay. So now we're at the part where we talk about our weeks, and what I'm gonna talk about instead is my next 6 weeks.
Jam:Okay. That's cheating. Okay. So means you can't share 1 for the next 6 weeks of episodes.
Melissa:So what I decided to do was Look at my next 6 weeks, which ends up being around December 17th, and figure out everything, every major task I need to do between now and December 17th thinking I would be really overwhelmed, but I actually think I will be able to Get all of my work done
Jam:Uh-huh.
Melissa:In that time. Jim and I are gonna be able to don't worry. We're gonna still put episodes out, but we're gonna take a 2 week break from recording. Mhmm. And I think I'll get at least a week and a half off from work in between This semester is before the new semester starts.
Jam:Nice. I'm
Melissa:very excited. I need to work a lot and get a bunch of stuff done. I may still work a little bit, But I will not have any urgent tasks over my break, which I'm very, very excited about.
Jam:Yeah. That is awesome, dude. Very cool.
Melissa:And things were a lot closer than I realized. So I only have 2 more chapters to teach in the class I'm teaching, which We get through 2 chapters in 2 class periods, so that's pretty quick.
Jam:Mhmm.
Melissa:And I only have Two class periods per chapter. And I only have about 3 more assignments in the course I'm taking, which is a lot less than I thought. Yeah. Yeah. So it's just things when I laid it all out, when it was feeling overwhelming and, like, I had a lot to do, When I laid it all out, it didn't seem as bad.
Melissa:It seemed a lot more manageable.
Jam:Dude, yeah. That's a great idea. Really, like, helps zoom out and Not feel a little bit, like, you know, daunted by the unknown, but it's like, oh, hey. I just mapped it out, and it's doable.
Melissa:And if I'm working on one of these tasks at any given time, then I'm being productive. So Yeah. It's nice. Yeah.
Jam:That's great.
Melissa:What about you? What's your what's your week shaping up like? Oh.
Jam:So for me, I I thought I kinda hit an interesting point in terms of work stuff where for a long time, and I'm sure many, many freelance type Folks out there know exactly what I'm dealing with too, but have basically been saying yes to everything. It's like Mhmm. Anyone who will hire me for stuff, it's like, just take the much on as I can because especially starting out, you know, it's like you're trying to fill up your schedule and to have more to do and obviously make more. And, I'm at a point now where I think I need to start saying no to stuff and to even taking some things off my plate. Yeah.
Jam:Because I have a little bit of an idea of, like, okay. I like some some of these things more than others or have an easier time kind of meshing these things with my schedule than other things. And I think I'm realizing that just a little late to a point where I have more on my plate A lot of times, a lot of weeks than I wish I did.
Melissa:You're a little over books.
Jam:Yeah. In fact, September wasn't quite that way. And then late in September, Then pretty much all of October was was like that. And so I'm making some decisions about how to remove some stuff because, just you just saying that you're gonna have, like, a week and a half off, in December from work, I was like, Oh, man. I don't know when, if ever, I would get any time off.
Melissa:You know? Oh, no.
Jam:And, Obviously, that's the downside of freelancing.
Melissa:Some time off.
Jam:Yeah. And that's one of the downside of of freelancing is that you have to give it to yourself and know that that means you're not making anything during that time Right. Unless you, like, took on more stuff before that or played catch up afterwards. So that's just you know, comes with the territory. But That's one of the things I'm trying to think through now and make some decisions about.
Jam:So not a happy thing. It's just sort of a state of the Just the state of JAMS Union address.
Melissa:Well, that's really exciting that you're getting A lot of work that you get to be choosy. That is a much better situation than feeling as if you're not making ends meet and you're not getting enough work.
Jam:Yeah. Yeah. And yeah. Yeah. For sure.
Jam:It's definitely a better place to be than being like, okay. I'm twiddling my thumbs. Well, someone please pay me to do something. So definitely better place to be.
Melissa:So, hopefully, you can figure out how to manage that a little bit better. And your update in A month or two is that you took a bunch of time off, and you are just somehow making all the dough. Yeah. Yeah. Well, that's exciting that you have a lot of interest in your business, but, also, I know it can be overwhelming to have so much work.
Melissa:So Thanks for taking time out of your workday
Jam:and
Melissa:out of your freelance to, and record our podcast and edit and make it sound incredible. We have the best quality. Thanks to you, Jim. And thanks for learning about and asking about how diapers work. You are responsible for so much of this episode, That's thank you so much.
Jam:Anytime, and thank you for teaching me and us. And on behalf of all the parents out there who have Scratch their heads about diapers. We we salute you.
Melissa:Well, maybe not me, but maybe Chemist who made the diapers.
Jam:Chemist. That's true. You did, like yeah. Remove the Shroud of Mystery for from it. So it does feel like we owe you thanks.
Jam:But, also, thanks for people who invented For sure. That you guys are the real MVPs.
Melissa:Yay. Chemistry for making parents' lives easier.
Jam:Absolutely. So, Melissa, I have a lot of ideas for topics chemistry in everyday life, but we wanna hear from you ideas like this, something like that. It's diapers every day. Parents are dealing with diapers. If you have ideas or questions like that, please reach out to us on Gmail, Twitter, Instagram, Facebook at chem for your life.
Jam:That's chem, f o r, your life to share your thoughts and ideas. If you like to help us keep our show going and contribute to cover the cost of making it, go to kodashfi.com slash chem for your life and donate the cost of a cup of coffee. If you're not able to donate, you can still help us by subscribing in your favorite podcast app and reading and writing our review on Apple Podcasts. That also helps us to be able to share chemistry with even more people.
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. Jam Robinson is our producer, and we'd like to give a special thanks to v Garza and a Colini who reviewed this episode.