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...

[@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

[@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...

[@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?

[@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.

[@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.

[@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!

[@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!

[@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

[@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

[@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!

[@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.

[@klorn32]

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

[@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.

[@wheeman999]

So glad you're making videos again.

[@harrisonbalduf3290]

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

[@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!

[@BirdSpyAustralia]

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

[@barrydavid6634]

it's kinda interesting isn't it

[@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 ...

[@IUNFE]

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

[@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!

[@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.

[@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.

[@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.

[@skyfeelan]

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

[@RealBenAnderson]

Explosive Liquified Bowel Movements

[@tommythai1043]

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

[@MichelPASTOR]

Good catch

[@CentralNintendo1]

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

[@dineshkumar-qs6sy]

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

[@SubhomMitra]

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

[@unlokia]

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

[@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!

[@jesutherland]

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

[@2kimports]

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

[@SaznizamSazmee]

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

[@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?

[@ScrewThisGlueThat]

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

[@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!

[@MaxVelez]

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

[@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.

[@Dimaz42]

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

[@pyotrleflegin7255]

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

[@originalscottfree]

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

[@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.

[@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.

[@mainemail528]

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

[@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.

[@BibekBasnet0]

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

[@IceyJunior]

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

[@abdullahsagheer6543]

These videos are always a pleasure to watch!

[@sjcea0512]

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

[@821Drifter128]

Thanks for making this piss easy to understand ;)!

[@firstnamelastname4752]

Sometimes KZbin's recommendations are spot on. Subscribed.

[@LifeOfPabs]

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

[@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!

[@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 !

[@phorth]

Always a wonderful lecture

[@rei_cirith]

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

[@Alexaflohr]

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

[@spikeman4pres]

Great Vid, Love seeing different types of Engineering

[@ChristopherWlezien]

Another tremendous video from The Engineer Guy!

[@lukezelechoski4504]

Great video, as always. Thank you

[@xenon9887]

Great as always, love your videos.

[@jeffreywillis9313]

Amazing explanation.

[@ToolTimeTyler]

Wonderful as always

[@dancollins4755]

Amazing! Thank you you are a great teacher.

[@DGFig]

Amazing video, as usual. Thank you very much!

[@LeFerret335]

Truly amazing video!

[@jamesshepherd5222]

I used to operate a diaper making machine. Complex and precise.

[@josefdawson5284]

this was much more interesting than I anticipated!

[@LifeHoThoAaisi]

Very good and important information shared. Thank you.

[@duckzor]

This was amazing, thank you!

[@unitedstatessc]

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

[@jmorv8866]

This is an excellent video to illustrate the internal dynamics of scientific engineering that goes into something as simple as a diaper. Furthermore, it can either prove or disprove claims made in advertising, so in essence, Bill proved that super absorbent diapers actually work. It's the 'how' though, that to me as well, is super fascinating. If I had gone into chemistry when I was younger, I sure wish I would have had Bill as a teacher.

[@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.

[@kheffah]

I love your videos! So informative

[@MH5XXXX]

Thank you sir.VERY INFORMATIVE.

[@FaizanAli-op2xe]

Awesome. Thank you for the video.

[@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.

[@TheProcessMan]

Never thought I would find a diaper so interesting

[@MrChangCJ]

absolutely intriguing!

[@Samuel126891]

well presented!

[@GoodDayFarm]

Love your videos! Great job! Thanks!

[@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?

[@Alphonse57]

love these videos. they are so interesting!

[@cashmiller2999]

Fascinating. Thanks!

[@Vitorruy1]

really cool video, thank you.

[@davidshi451]

Great video!

[@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.

[@jr52990]

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

[@naushilb]

Your videos are awesome!

[@dedede5586]

How does this guy make everything so interesting??

[@ChrisSmith-st8of]

Love your videos very informative thank you!

[@bosapiutsa3829]

Great work, fascinating engineering!

[@BGTech1]

Hi there

[@lyleblue6739]

This was cool and interesting to learn. Thanks :3

[@MihirrPanchaal]

fascinating video.

[@_RiseAgainst]

Great video.

[@TheRednaxela12]

this channel is amazing