The Engineering of a Disposable Diaper

Bill reveals the stunning engineering underlying the design of a diaper. He describes the five layers of a diaper, including the superabsorbent polymer in the diaper's core. He illustrates the action of this polymer with a stunning demonstration using a single bead of polymer: it soaks up enough water to grow from a diameter of 4 mm to nearly a half inch.
You can bundle watch Bill's videos using this playlist:
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If you are interested in mechanical computers you'll likely enjoy his series on Albert Michelson's Harmonic Analyzer -- a 19th century machine that calculates Fourier transforms:
• Albert Michelson's Har...
Creative Commons Images Used in Video
First cotton image is by dotlizard
www.flickr.com/photos/dotliza...
The cotton candy image is from Stefano Mortellaro
www.flickr.com/photos/fazen/7...

[@kyle-silver]

It just struck me that almost none of the mechanics of these diapers rely on gravity, meaning that no matter what the position of the baby (laying down, on an angle) the diaper will be equally effective.

[@engineerguyvideo]

That had not occurred to me, but of course that's true! Good observation.

[@johnnychang4233]

Isn't modern diapers also a result of space exploration and it's associated inventions? Of course they designed it to work under zero gravity.

[@kyle-silver]

Disclaimer: do NOT hold your baby upside down to test this!

[@DarknessLPs]

on the contrary, hold the baby upside down and for added effect, shake it quite vigorously to test the adherence to the child

[@trinhkets]

you need Jesus...

[@PracticalEngineeringChannel]

This is fascinating. Excellent job covering a tricky topic with professionalism ;) In civil engineering we have woven and non-woven geotextiles that serve different purposes as well. Great work as always.

[@lioraselby5328]

Hey look, it's one of my favorite engineering KZbin channels commenting on my other favorite engineering KZbin channel!

[@ttykv]

engineerception

[@Seff2]

youtube is awsome :D

[@zoppp621]

I just subbed to you a couple days back. Keep up the great videos both of you!

[@loucummins7918]

Practical Engineering you might know this. How were the kings pyramids of Egypt built? I'm wondering if either you or engineering guy can help. Love both your channels.

[@FilmmakerIQ]

Not sure if this is my number 1 favorite video on diapers.... or number 2.

[@traxonja]

Haha

[@markfryer9880]

Oh your going to diaper hell for that one! ; )

[@lemonke8132]

Hahahaa

[@tohopes]

Either way, we've got you covered.

[@rafetizer]

lmao

[@BluDog35]

"Stagnant Pool Of Evacuated Urine" The name of my new metal band.

[@kahlzun]

I like it!

[@Scars_House]

ime sorry but ...."explosive liquified bowel movements" is much more catchy

[@hoilst]

Wasn't that a Cannibal Corpse song?

[@operator8014]

Save ink, just go with, "S.P.E.U." ...

[@ewanwilson1974]

BluDog35 I would love to see someone announce that for a concert.

[@MonMalthias]

I wonder what the guy at the patent office thought when he read the sentence, "explosive liquified bowel movements".

[@Tumleren]

"Yeeeup, bad mexican food'll do that to ya"

[@Aelfraed26]

Freaking Chipotle. Why does it have to be so good?

[@BobWidlefish]

"I bet Taco Bell is going to sell these with every order and make billlliiioons!"

[@catfish552]

If he was a dad, probably something like "Oh, thank god for that..."

[@ezekiel0606]

Palider south park?

[@holtek86]

I have been working in this industry for over 30 years so I do get to see the machines that make diapers and similar disposable products every day. When I started, 400 products per minute was considered fast and everything was driven by a lineshaft and belts. Now it's hundreds of servo motors synchronized together with incredible precision and well over 1000 products per minute is a reality. Thanks for explaining the product so well, we do kind of take all this for granted but there is quite a bit of engineering that goes into it!

[@nickkillian]

You know, as a first time father (7 month old child), I have wondered just how the basis of disposable diapers worked. I knew it had to be something far more than meets the eye. Now I know, thank you.

[@derickb8713]

I am impressed that at only 7 months old you are already a father. 😆

[@Getyurfactsstrait]

I used to work on diaper machines and what you said at the end is so true. I was amazed at how fast these machines would run. We were a smaller company and the machines ran at 650 dpm. Even at that speed it's was really something to watch. Everything had to be synced up perfectly for the machine to operate properly. One of the most interesting parts of the machine was the vision system which would reject any diaper was out of spec while running at full speed.

[@AlondraSanchez-wl2js]

I work at a diaper plant and our machines run at 800 dpm and it’s spits them diapers out like crazy

[@muntasirnasimtasif5434]

Hi, may I know the origin/supplier of those equipment?

[@randallvoth8810]

I just finished a 33 year career making diapers and pants. Our fastest machine was capable of 1200 dpm!

[@stevesynan3910]

I went in thinking 'what could possibly be that interesting about a diaper?' and now I'm completely blown away by materials science and need to learn more! Great job as always!

[@peterlinddk]

I love videos like this one and the one about aluminum cans - stuff that we think of as simple "throw-away" items, but in fact contain a lot of ingenious engineering solutions! A shame that we can't get to see the manufacturing process.

[@Tunkkis]

I'd wager many of those clever engineering solutions are the reason they've become so disposable, through being so efficient to manufacture.

[@robinlaszlo]

Honestly, SAP is super bad for the environment to throw away and nothing about the science makes it "better" or "easier" to dispose of in the long run.

[@klorn32]

I just discovered Bill and his channel. I could listen to him talk all day. Great voice and presentation.

[@itcamefromabox]

Listen Bill, I don't want to freak you out but we fall asleep to the sound of your voice at night. I'm not saying you're boring because we love your content, i'm just saying you have a soothing voice. KEEP UP THE AWESOME WORK :D

[@superluig164]

We? Speak for yourself.

[@marrs1013]

It Came From A Box Called accidental ASMR.

[@jakobarend4526]

tinylilmatt literally my go to channels

[@bfoot2211]

I’m proud to get my friends to subscribe and Bill from one father to another thank you for getting my three year old to sleep. Doug Demuro could only dream to have a voice and a presentation Elegance such as yours. Keep up the great work it is true fascinating relaxing. I wish more KZbin video producers would relax their attitude and truly research before they open their mouth in front of a camera. If you haven’t heard of the channel “Brooklyn Duo” they are a classy family of musicians that your family might enjoy. I’m looking forward to your next upload.

[@douglasparkinson4123]

i use engineer guy videos as calming for if im panicing for something coming in the future

[@wheeman999]

So glad you're making videos again.

[@DanBillings]

I'm a UIUC engineering alumnus and these videos make me very proud. Always incredibly informative and the production is airtight. Thanks to Bill and your team!

[@DEVILMATE1996]

TIL babies pee at 6 mph.

[@zeroforconduct8008]

They pee faster. The absorption happens at 6 mph, not piss coming out of the dick.

[@Jack-vp6wc]

TIL babies must be moving at more than 6 mph to pee. /s

[@bentleyboy72]

@@zeroforconduct8008 Watch the video again. He clearly says "it (urine) strikes the topsheet at over 6 mph."

[@danielflanard8274]

@@bentleyboy72 "at over 6 miles an hour"

[@jimbo80982]

Depends how fast it's running at you

[@BirdSpyAustralia]

I was not expecting to be learning about diapers tonight, but here I am. :)

[@barrydavid6634]

it's kinda interesting isn't it

[@Fire-in-the-sky]

I fucking love your videos man. keep it up!

[@hacehase]

thumbs up

[@ronshaw80]

Is that language REALLY necessary? Makes you sound really professional.

[@CaalamusTube]

They're just words man. Stop trying to police people. It's not as though he was abusive or derogatory! On the contrary, his use of the word "fucking" served to convey positive regard. ...or, at least if you *ARE* going to insist on trying to police people ( in KZbin comments of all places :P ) Stop being passive aggressive! 1st Amendment... *FUCK YEAH!*

[@Fire-in-the-sky]

+Ron Shaw what gives you the idea i was trying to be professional? we are in KZbin not a a FUCKING job application. +Bilb Ono oh what a great insult. 10/10 man

[@Fire-in-the-sky]

+Caalamus thanks man, some people just like to bitch about everything.

[@unlokia]

The engineering in this invention is INCREDIBLE. God bless you, Bill, and thank you for all your hard work and effort. Matthew.

[@HPerrin]

I love how passionate this guy is about any engineering advancement. We could make a device to better fling shit at a wall, and Engineer Guy would love it as long as it was engineered well. That's the kind of spirit and wonder we need to teach children. Keep making these awesome videos!

[@rym6060]

I don't even know what's happening in half of his videos, but it's very soothing and interesting to watch/listen to so I get completely lost learning about diapers and coffeemakers ...

[@fat_boy_slim]

The only man who can make diaper engineering sound interesting, love this channel

[@DIYTyler]

My mind just exploded! Need to make that many a minute to keep the cost down.....might be a neat place to work.

[@SubhomMitra]

This is just so impossibly fascinating! Thanks for making such great content; can't wait for the videos on Faraday.

[@harrisonbalduf3290]

This man could narrate anything and I'd watch it.

[@NewMetallica]

Bill your videos really make my day! I am always amazed at some of those things that are so self-evident in life have such interesting engineering stories. You rock!

[@IUNFE]

I am not an engineer, but you make me want to be one. Thank you for the informative video.

[@jayweb702]

Well Bill thank you very much for making this informative video. I used to work for Paragon Trade Brands years ago as a machine operator who made these diapers and I'm still fascinated by the production process as I never never operated any machine like it since.

[@RealBenAnderson]

Explosive Liquified Bowel Movements

[@dineshkumar-qs6sy]

This video should be an example of how concepts should be explained, perfectly done. Excellent work. Thanks for the details.

[@CentralNintendo1]

At 3:00 the millimeter numbers are mixed up, it's supposed to say "2" "1.5" "1" "0.5"

[@tommythai1043]

3:04 Shouldn't the labels for 1mm and 1.5 mm be swapped?

[@MichelPASTOR]

Good catch

[@pyotrleflegin7255]

That is truly amazing! I would never have thought it was anywhere near this complex a system. Thank you for a marvellous channel!

[@Dimaz42]

I’ve never thought that I would enjoy watching how diaper works.. great explanations, Sir! 👍

[@jesutherland]

I"m really enjoying the longer form videos. Thanks!

[@MaxVelez]

Beautiful explanation of such an important modern technology. Love you Bill!

[@sjcea0512]

Your videos absolutely amaze me! You are making me look at things totally different than I ever have before

[@abdullahsagheer6543]

These videos are always a pleasure to watch!

[@AMULET72]

as the daddy of a nine month old baby boy this is very interesting and I am glad that I can buy them and get the benefit of their creation. I can still see my own mom washing cotton nappies by the dozen and drying them on a line outside in the air. hard work and a lot of waste water, heat, detergent etc.. but still, over four million nappies a day disposed of in the UK makes me wonder about the effect of this manufacturing process and their disposal. either way, hats off to the people who made this possible. necessity being the mother of invention and all that.....

[@RonJohn63]

Diapers are a tiny fraction of the waste stream that winds up in landfills.

[@dimesonhiseyes9134]

Pro tip : you can use diapers to help a wound to stop bleeding. The inner 2 layers do a great job of promoting coagulation.

[@skenzyme81]

Stunning video. Your series is like nothing else. When you and your team get picked up by a network, please strive to maintain your excellent standards.

[@jwoodCAD]

Man, you sure know how to convey your fascination; if someone had told me yesterday I'd be enthralled by a video on the workings of diapers, I never would have believed it!

[@CatherineLu]

This was so cool. I'd never thought that much about how these things work. Modern technology is astounding. Also, great presentation on a topic that could easily become unnecessarily funny.

[@2kimports]

Excellent video Sir! , Please do not stop making these! They are fantastic!

[@LifeOfPabs]

this takes how its made to a whole new more interesting level! thanks for sharing this knowledge

[@SaznizamSazmee]

As a new dad, I can now appreciate the beauty in the engineering of a diaper.

[@DGFig]

Amazing video, as usual. Thank you very much!

[@mikestoneadfjgs]

I clicked on this video thinking it would be boring, but boy was I wrong. I had no idea that something as common as a diaper had such fascinating engineering. Excellent video as always.

[@xenon9887]

Great as always, love your videos.

[@IceyJunior]

You should make more videos and upload them frequently ! So knowledgable !

[@spikeman4pres]

Great Vid, Love seeing different types of Engineering

[@mainemail528]

My favorite channel and my number one favorite video of this channel!!! Long live "The Engineer Guy"

[@rei_cirith]

Amazing... This was actually really cool to watch. Thanks!

[@thomasdarby6084]

I've worn adult diapers for over 20 years since two strokes left me partially incontinent. The ones I use don't have the plastic outer barrier, but they work the same as a toddler's pull-ups. Thankfully I have not had to test their capacity!

[@McRocket]

Wow...I have seen possibly all of your videos and enjoyed all of them. But I thought this one would be different. I was wrong...I am surprised at how fascinating a diaper is.

[@SeaOfMadness]

As the parent of a 1 month old boy who shits like a seagull, and therefore gets through hundreds of these things, I found this both interesting and reassuring. Another awesome vid - Thanks !

[@lukezelechoski4504]

Great video, as always. Thank you

[@Alexaflohr]

This is incredible, man. You just earned yourself a subscriber.

[@ChristopherWlezien]

Another tremendous video from The Engineer Guy!

[@EngineerNick]

That was an awesome explanation

[@wannabepvm]

Your videos are absolutely great. Originally had no interest in the subject and stumbled across the videos. Love the way you present your subject. Would love to see similar videos about electrical parts as its my trade.

[@BibekBasnet0]

what a well-researched, well-made video. kudos.

[@ToolTimeTyler]

Wonderful as always

[@hadireg]

Amazing reaction of those polymeres indeed! wonder how many out there know about it! :) Thanks for this channel!

[@JoelReid]

The top layer resisting water transfer is why nappies are not very good at mopping up spills. When wiped across a spill the nappy will take some of the liquid, but leave behind many trails of liquid. To absorb all the liquid in a spill one is required to press down firmly on the spill, but this risks pushing out the absorbed liquid in when there is excess, and is inefficient when compared to something like a paper towel. Nappies will not float on water if placed inner side down (which is difficult), when tried then it will absorb fluid from the sides and then become full and sink. Nappies however do not leak from the sides unless it becomes full.

[@GoodDayFarm]

Love your videos! Great job! Thanks!

[@kheffah]

I love your videos! So informative

[@ScrewThisGlueThat]

Great Documentary... I am stunned at your knowledge and professionalism.

[@Nipplehook]

Im a new parent and for the past 6 months Ive used those exact diapers and at more than one occasion I thought about how amazing those things are, they really do hold so much liquid, yet keep the baby dry at the same time. Its so ingeniously designed and so much thought went in yet a single diaper costs almost nothing and we use and dispose thousands of them without giving any thought.

[@skyfeelan]

not planning to have a kid in the near future, but I really love the engineering principle behind it!

[@josefdawson5284]

this was much more interesting than I anticipated!

[@CheeseWithMold]

Can't wait to see what other normal everyday object you dissect next. It's amazing what type of stuff we take for granted.

[@821Drifter128]

Thanks for making this piss easy to understand ;)!

[@PlanetRockJesus]

That was totally cool!

[@nelsondisalvatore9812]

the only bad thing is that it is practically unrecyclable

[@honestytoafault]

not so. the absorbent layer is great for retaining moisture in soil.

[@lyrimetacurl0]

@@honestytoafault would that be good for the Chinese tree planting project in the desert?

[@Visitor2Earth]

I have read several environmental studies over the years comparing the effect on the world of a disposable diaper vs the effect of a cloth diaper that needs water and chemicals and energy to be cleaned/dried. Surprisingly, cloth diapers had more of a negative impact than single use cloth diapers on our environment...very surprising results!

[@nelsondisalvatore9812]

@@Visitor2Earth realy you have read so, even you are a 12 years old ginger?

[@letsmakegadgets6899]

@@nelsondisalvatore9812 What does that change? Is he not allowed to do research because you believe he shouldn't?

[@LeFerret335]

Truly amazing video!

[@phorth]

Always a wonderful lecture

[@MrChangCJ]

absolutely intriguing!

[@duckzor]

This was amazing, thank you!

[@LifeHoThoAaisi]

Very good and important information shared. Thank you.

[@jr52990]

I agree, it's often the simplest things that are the most amazing.

[@Alphonse57]

love these videos. they are so interesting!

[@lyleblue6739]

This was cool and interesting to learn. Thanks :3

[@floridarealestate5715]

Great work, Subscribed! Very informative. You made diapers interesting for me.

Wow, amazing how such a common thing can be such advanced.

[@FaizanAli-op2xe]

Awesome. Thank you for the video.

[@jeffreywillis9313]

Amazing explanation.

[@originalscottfree]

I never gave much thought to diapers however after watching this video... Wow, I am amazed.

[@DekuStickGamer]

I really love learning the everyday engineering that goes into things I use. They're so hiddenly complex, it astonishes me that thought actually went into it in the first place.

[@aegisfate117]

Makes me wonder if everything is actually man-made and man-thought. An alien race could be inserting this knowledge secretly into the human consciousness to speed our technological development.

[@aegisfate117]

Imagine trying to make a toaster by yourself (there's a Ted talk about this). You could never do it because it requires too many specialties coming together. With all that knowledge out there that you do not need to understand and could never understand creates the perfect backdrop for physically possible things to be secretly revealed to humans through their "chance experiments."

[@DekuStickGamer]

Wow...there's some truth to that. That's really interesting. Have you got a link to the ted talk?

[@DekuStickGamer]

Though I'd have to refute the alien statement. I think it's perfectly possible that the creation of these complex devices came to be. A need arose, demand was high, great minds created ideas and collected and a product that we use now was developed over time. A new ideas continue to come. Or are you reffering to something else entirely that I've misunderstood?

[@unitedstatessc]

I'll get you some video of a diaper assembly line. It really amazing, they use these really complicated

[@orchdork775]

It's incredible how much science and effort goes into perfecting the seemingly mundane items of every day life.

[@linguine4500]

Anything to cut down on costs

[@davidshi451]

Great video!

[@wizardOfRobots]

really opened my eyes to how a diaper could contain so much precision engineering!

[@nerdheroes]

Hello, Glad so see two new videos back to back. I wish you would have touched on the negative environmental impacts of so many plastic diapers. They are definitely cool tech though.

[@cashmiller2999]

Fascinating. Thanks!

[@firstnamelastname4752]

Sometimes KZbin's recommendations are spot on. Subscribed.

[@dancollins4755]

Amazing! Thank you you are a great teacher.

[@GranVlog]

I love this guy

[@TheProcessMan]

Never thought I would find a diaper so interesting

[@MoeRubenzahl]

Definitely the first time an engineering lecture has included the words, "explosive liquefied..." well, you know. Nicely done.

[@bosapiutsa3829]

Great work, fascinating engineering!

[@BGTech1]

Hi there