Rookie Science: How Does a Diaper Work?

Kids Club
Video Transcript:

Hi there. I’m Larisa. I’m a children’s staff member at Charlotte Mecklenburg Library. And today we are going to dissect a diaper. A clean diaper, just for the record. So, if you have little brothers and sisters, or if you just know some babies, or even if you don’t, you might be wondering—how do diapers work? How do diapers keep little kids clean? Well, let’s take a look.

We’re going to start with just a regular ordinary diaper. And I have cut a hole in it. What we’re going to do today is take a Ziploc bag—an ordinary Ziploc bag, and we’re going to take the stuffings out of a diaper. You might have noticed that diapers feel like they’ve got a little something in them—like cotton or something. Well, would cotton keep the baby dry? Let’s see. We’re going to take that stuffing out and just drop it in. So just go into that clean diaper, and pull out that stuffing. You might notice as you do this that you’re getting some white powder on your hands and some stuff that looks like a lot like cotton. But is it? Let’s find out. We’re going to take a whole lot. And you’ll notice that even though it seems like we’re pulling a whole lot out of this, there’s still going to be a lot left inside the diaper. So, this should be a good start. What we’re going to do, we’re going to seal up the bag. That’s why a zipper bag is important. We want to make sure that the seal is done completely tightly so that we don’t lose any of this stuff out of the bag. And then we’re going to shake this up a little bit. I like to shake! As you shake, you might make some observations.

You might notice that there are some white—not quite powder, but not like the cotton stuffing bouncing around in there. Like little tiny balls almost. It’s separating out from the cotton. So, shake it a little bit more. And pull it towards the corner. Going to open up the bag again. Because what you’ll find—if you take all that cotton out. Take the cottony stuff out. And we’re going to put it in one cup and set it aside. We have this white powdery stuff. It’s not, it’s not powdery like flour would be, but it’s still a powder tucked into the corner. We’re going to take that small amount of substance, and we’re going to shake it from that corner of the bag into a cup of its own because we want to see what happens when we get it wet. Kind of like would happen in a diaper, right? So we’ve got—we’ve got a little bit of cotton it looks like in here; I’m going to take that cotton out. And notice we’ve got a little white powdery stuff in here.

Next, I’m going to take a dropper. And I’m going to count my drops as I go because we’re going to do the same thing to the cotton. We’re going to count how many drops of water we’re going to put in there and see what absorbs better—the cotton or this little powder. Let’s see. One, two, three drops of water. So we’ve got some water in there. And we’ll put the same over here. One, two, three. And I wanted to use the dropper just so that I knew that I was getting about the same amount of water into each cup. So we’re just going to give it a moment to see what happens to the white powder. So the white powder is actually what’s called a hydrogel. And hydrogels are these little tiny objects that are—they’re a type of material called a polymer. And a polymer is made of lots of molecules that like to absorb a lot of water, or in this case, with a diaper, a lot of liquid. And so, when they absorb the liquid, they expand—they get bigger. And so they’re teeny tiny at first, and they get much bigger. So we’re going to look and see what happened and how well we absorbed the water.

So, if you look, that little amount of white powder has changed completely. It’s now this clear kind of crystal looking substance—a gel substance. We’re going to try testing it. We’re going to touch it with our fingers. And our finger comes away, and it’s not wet. It doesn’t feel as wet as it would it if you were sticking your finger into water. It just feels like a gel; whereas, if we pick up our cotton and we squeeze, you’re going to get wet. It’s going to have some water. And you can see the water in the cup too where it’s dripped off of the– off of the cotton, too. So, this is a hydrogel—that’s the magic ingredient in a diaper. That’s the ingredient that makes the diaper absorb liquid.

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