The Secret of Floppy Paper - Numberphile

Tadashi is back, this time looking at drooping paper (and toilet paper).
More links & stuff in full description below ↓↓↓
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A NOTE ON THIS VIDEO:
A few of our Tadashi videos blur the already blurry line between mathematics and physics... Some people suggest they may be a better fit on Brady's dedicated physics channel (called Sixty Symbols).
In response, the reasons they are on Numberphile are:
1) Tadashi, while certainly a modern polymath, is based in a mathematics department.
2) This sub series (with its animation and extra production work) has been supported by the Mathematical Sciences Research Institute, a Numberphile collaborator.
3) Some of the previous and future Tadashi videos are more math-oriented than physics - and it just makes sense to put them on one channel rather than dividing the series between two channels on an ad hoc basis.
In a multi-disciplinary world, it is challenging to run KZbin channels which people come to associate with just one discipline.
That said, feel free to go over and watch hundreds of physics videos on Sixty Symbols --- / sixtysymbols

[@twalton]

Tadashi is one of my favorite stars of this channel. "I don't know if it's the first time that toilet paper makes an appearance in numberphile..." XD

[@SeleniumGlow]

Agreed. This man has an amazing sense of humor.

[@garbage63]

That toilette paper was terrible.

[@francomiranda706]

+BocoCorwin Rob is being terrible, while the toilet paper is being tearable

[@timothyrades9831]

Number2phile

[@Blackmark52]

I'm very familiar with paper grain, but the insight into their role in toilet paper was absorbing.

[@ObiWanCannoli]

Toilet puns

[@jonahlee8894]

HAHAHAHAHAHAHAAA

[@chucksherron]

👍

[@anantdixit3831]

You win the internet!

[@rparl]

(Pun acknowledged) A recent trend in commercial TP is the use of unperforated paper. This shows why it doesn't work well. (End rant)

[@Amphibiot]

This guy has the magical gift of making any boring subject incredibly interesting. He is absolutely fantastic.

[@SithBowman]

For more info on Gaussian Curvature, find the video numberphile made called "The Remarkable Way We Eat Pizza"

[@numberphile]

yes, it is also linked in the video description of this video. or it is right here: kzbin.info/www/bejne/nZqQhXWinZlnnbs

[@dlee645]

I was thinking the exact same thing.

[@arturmizuno]

KLEIN BOTTLES

[@42scientist]

+Artur Mizuno there is no link but klein bottles are cool

[@Cadrid]

I will never get tired of Tadashi videos. Does he have a superpower to make math interesting? I mean, he just talked about paper rigidity--including toilet paper--and I was riveted. That's not natural!

[@tiuk23]

Im a simple man, no matter what is video about, I see Tadashi, I upvote.

[@JRCSalter]

As an amateur bookbinder, I am fairly chuffed with myself for knowing the solution before he said it.

[@andrewwong200]

Vocab word of the day.

[@ImmaterialDigression]

This man needs to start a mathematical toy shop

[@letoiiatreides2466]

I'd buy his toilet paper.

+

[@QMPhilosophe]

But I'd get it new...even tough used is probably cheaper.

[@slendy9600]

he needs to partner up with Tim from Grand Illusions

[@direc85]

Perhaps he could team up with James Grime ;)

[@bwatspro]

Toilet paper from Mathematical Sciences Research Institute. The feeling when toilet paper has better credentials than you.

[@AlRoderick]

There should be a link to the gaussian curvature video with the pizza slices that you did with the Klein bottle guy. That was the big math thing in this one and he breezed past it pretty quick.

[@numberphile]

Here you go: kzbin.info/www/bejne/nZqQhXWinZlnnbs

[@BhupinderSinghSaini1]

+

[@Sam_on_YouTube]

Having seen that video, I figured out what was happening as soon as he started moving the binder clip.

[@pavphone2616]

"Klein bottle guy" sounds like a fun superhero name

[@Sam_on_YouTube]

+Pav Phone You could get some great supper powers out of that. Able to walk through walls using the 4th dimension. Lock him in a box and he'll always be outside of it.

[@dave5194]

Never thought I'd learn something about the engineering of toilet paper on numberphile, that was pretty cool

[@vasilivanich3842]

Our body has a certain anisotropicity to itself as well. One can easily find it out when trying to use toilet paper in perpendicular fashion to the usual way.

[@gimpdoctor8362]

yes it's also very easy to tear someone in half vertically but much more difficult to tear someone in half horizontally. You can try it at home.

[@MIbra96]

+Ben Nutley I tried it with myself but it hurts a little.

[@Borednesss]

Muscles and bones are anisotropic, I guess

[@samhaberman]

Absolutely incredible. One of the best Numberphile videos for sure.

[@numberphile]

that's kind - cheers for watching

[@nathanielsharabi]

thank you for giving me the wisdom of the structre of toilet paper🙏

[@ricardo.mazeto]

I love when people explain mathematical concepts with easy real life examples.

[@TheFreezeChill]

Nope, thats physics.

[@ricardo.mazeto]

TheFreezeChill Physics is a branch of math.

[@theangrymathematician9121]

+Ricardo Mazeto Or rather should be. If you ever took advanced physics it is mostly statistical simulations used rather than analyitical methods.

[@theangrymathematician9121]

+The Angry Mathematician Then again statistics is also a branch of math. Huh. I am drunk.

[@L3ON360Z]

that's one of the best things about Tadashi. He always does this :)

[@johanng2]

I would freaking love to have Tadashi as a math teacher. It's like these weird brain goosebumps I get every time I watch something of his.

[@zahbaz]

1.) As a researcher who deals with anisotropic materials, I found this to be a very beautiful demonstration. Thank you for sharing. 2.) This Numberphile video was dangerously close to discussing a different sort of "brown paper."

[@villanelo1987]

About the video description... I think it was perfectly fine to put this video (or others from Tadashi) in this chanel. It is true that they show concepts in a different way then others, but in the end, he is talking about mathematical concepts most of the time (gaussian curvatures in this case), the difference is just that he has applied examples of said mathematical concepts instead of the usual theorical explanations. I mean, I know this is just the opinion from some random guy on the Internet, but reading that description made me think that maybe some people is complaining when Tadashi appears, so I just wanted to offer a different opinion. I love his videos, and I think they fit perfectly in here.

[@batfan1939]

I love the applied stuff. It really compliments the theory videos!

[@23Scadu]

I'm not too concerned with whether Tadashi's videos go up here or on Sixty Symbols (I subscribe to both anyway) as long as they keep coming. They're absolutely delightful.

[@chucksherron]

Tadashi said he's becoming SmarterEveryDay.

[@The0x539]

And he introduced some Objectivity into things.

[@Gremlins422]

Its nice to see some PeriodicVideos of Tadashi on Numberphile.

×

[@Gremlins422]

Jan Cillié Louw Now the question is: What is x?

[@itskelvinn]

Destin is borderline a douche. Hes so rude and always interrupts his guests to make his lame jokes. I feel like he tries too hard to make himself seem like a science expert rather than teaching his audience.

[@brianpso]

"Everyday I get a little smarter" This is my way of life and I feel proud to know that it is yours too, master.

[@invaderpopz]

I love tadashi and I loved the connection to the Gaussian curvature! I only understood that part because I had previously watched the pizza video :) now I feel smarter

[@Anolaana]

Hooray, I'm not the only one who remembers Cliff's video about Gaussian pizza curves!

[@Mephistahpheles]

Love that this guy does so much with stuff simply "around". In grade school, I recall the difficulty in science classes when told to "come up with your own experiment". MANY students had no idea WHAT, nor HOW. (Sadly, I didn't have a teacher that inspired. It was nearly all memorization.)

[@JeoshuaCollins]

**Bows deeply** Thank you, Tadashi. That was wonderful. I would love to see more videos from you and your toys.

[@pinkdispatcher]

The straight vs. across tearing works very well with newspapers, which use very anisotropic paper. And it makes for a nice party trick, asking people to tear it in a straight line, and after demonstrating how good you are at it, you hand it to them, but rotated 90 degrees.

[@Ambidextroid]

I love his accent, it's somewhat like "engrish" but at the same time incredibly clear and he pronounces words really nicely. I can hardly say "rigidity" without it sounding like a total mouthful.

[@briandeschene8424]

Ambidextroid He has lived and studied in Japan, France, and U.K. so I believe his accent and vocabulary is a wonderful blend of those very different ingredients. I hear aspects of all three languages when he says certain words and phrases.

[@superj1e2z6]

It's your boy Tadashi TOYkieda!!!!

[@nymalous3428]

I love mathematics, of all kinds, but Tadashi seems to apply mathematical principles to what most people would consider to be non-mathematical circumstances. And he does it in such a way as to be fascinating! He is just wonderful to listen to! (And he is actually the first person I ever saw who did math with his fingers and toes...) Thanks for sharing this!

[@verdatum]

Speaking as a woodworker, and massive fan of composite materials, "anisotropic" is like the best term I've learned in MONTHS!!!!!!!!!!!!!!!!!!!!!!!!!

[@naikshibabrat]

I agree with the above response. A scientist once said "Mathematics is the language of physics", or in this case mechanics of solids or deformable bodies. In applied mechanics and mathematics, these problems are studied using PDEs and experiments. When mathematics is done for the sake of it, as in pure/abstract, we always find some new applications/physical problems that use those tools. For example, Hardy's work on number theory that is used in cryptography.

[@SocksWithSandals]

I just understood anisotrppy and Gaussian curvature but watching a bloke play with bog roll for five minutes. Great teacher

[@platinummyrr]

this man is an excellent teacher! He really makes things feel exciting and ensures that the listener wants to go learn more on their own!

[@nassar8]

i love the videos you do with Tadashi. effortlessly entertaining and often intellectually challenging at the same time, a winning combo!

[@ExhaustedElox]

Tadashi-sensei breaks down why mundane things work the way they do so cleverly and clearly. He is a great educator.

[@darkmage07070777]

2:00 - "And we shall call him...Mini-Todashi."

[@maldoran9150]

What a great teacher!

[@Teth47]

I'm at 1:20, here's my guess: Paper is stored on large cylindrical reams before it's cut, it retains some of this curvature as a bias to bending in one direction over the other. You flipped the squares after cutting them so that when laying on one side, gravity plus the top paper's bias overloads the bottom paper, which would want to curl upward. When you flip, the bottom paper is biased downward, and the upper paper is biased upward, so they separate. You also rotated the original bottom square 90 degrees to produce the same effect when you precess to the next edge. Let's see if I'm right. 3:43 I overthought it. At least I was close!

[@sitearm]

nice! also explains why it's hard to tear out articles from the newspaper - up and down tears easily by hand but horizontally have to crease hard or use scissors : )

[@SaveSoilSaveSoil]

I have been interacting with paper for decades but never noticed these hidden secrets! Love Tadashi!

[@chrisbell8207]

I want him to read me bedtime stories

[@jbrowsingj]

Truly amazing. I could listen to this man explain anything for hours. Such a talented teacher!

[@SquirrelASMR]

Wow awesome! I wasn't expecting that, I was expecting a trick like him sliding the paper slightly. Awesome

[@RodeyMcG]

The Tadashi videos are such standout highlights in this channel. Just excellent

[@danielgrala7538]

"would Mr.tadashi please return the toilet paper to the bathroom for its intended purpose."

[@HerrLavett]

Relaxing video. It is now clear that I will watch and listen to anything Tadashi says about anything, anytime.

[@40GallonTophat]

This dude always has the best videos. He finds the most fascinating properties about everything!

[@astrielmaahes1116]

I discovered this property of paper when i was 10. I did origami all the time and realized folds going in one direction would be easier to make and less rigid than the other perpendicular direction.

[@andsunds]

The grain orientation in toilet paper is more of a consequence of how the paper is manufactured. You want to be able to roll up the paper into the toilet paper roll as it's manufacture, so it's produced by spraying paper pulp onto a conveyor belt where it dries and is afterwards rolled onto the roll. This makes the fibers line up along the length of the toilet paper.

[@brigadierliane]

I love the animation when Tadashi is the one lecturing

[@TheGreatRepertoire]

Very interesting. Thank you for your great videos.

[@egalomon]

Drawing a tree on the "right" paper, but only the japanese (or rather, chinese) character for "tree" on the "bad" paper. Nice detail!

[@TheShnitzel]

Tadashi is so fun to watch! He explains very cool things in a really understandable way!

[@oogalook]

The most comforting voice I've ever heard. Like a mattress of butter.

[@ricodelta1]

I watch Tadashi's videos primarily to listen to his voice. It's quite soothing

[@mrninjadude100]

As a Materials Science Major, this is actually really awesome to see.

[@RedellaStrada47]

5:51 "I found (stole) this" XDAnyway, this is the difference between normal people and reflective people: we find something interesting in ANYTHING!

[@RalphDratman]

What a great teacher. Thank you Tadashi and of course Brady (who is silent in this one).

[@closair]

Tadashi has a very interesting way of thinking, and I learn cool stuff from these videos!

[@theatheistpaladin]

I love Tadashi. Turn math concepts into practical yet rarely known factoids.

[@Veptis]

We work with paper and cardboard in school. Right now we do book binding, so I knew the answer really quick.

[@alexanderschestag3247]

Tadashi is great. Even I understand everything he explain.

[@Chowder0o]

This is the only man who can make me watch a seven minute video about paper.

[@florianju5638]

So cool to watch Tadashis Videos :) Really basic stuff with a strong relation to everyday life. That makes it so interesting for me. More please!

[@ceruchi2084]

Tadashi and Stoll are the best for bringing math into everyday life

[@nathanjxaxson]

Tadashi-sensei is awesome. (Actually, most of the personalities on this channel are.)

[@Aleph_Null_Audio]

I always get excited when a new video with Tadashi comes out.

[@charlesfudge2]

Awesome, more Tadashi. Keep the videos coming!

[@Srinamamuduli]

This Guy A Genious.Always Out Of World Thing.

[@paulbentley2709]

Brilliant. What a demonstrator.

[@GoldenBoyz2000]

I have now watched every tadashi video.. I need more!

[@andriypredmyrskyy7791]

I do shodou too! Tadashi just keeps getting cooler.

[@gogyoo]

The ideogram for "tree" mutating into the picture of an actual tree was a nice touch!

[@giorgigogashvili2549]

One more usage of directional strength is in plastic bags, the long polymer molecules are aligned from the handles to the bottom.

[@AxeManAnthony]

Only Numberphile can manage make an educational video about toilet paper construction this damn interesting.

[@MindCraft4You]

This guy has the best videos. Keep up the good work guys :)

[@ColorNerdChris]

1. Tadashi-san rocks. 2. Printers are intimately aware of the grain direction of grain of paper, so much so that if you buy larger format paper (in the US) you may see some listed as 11x17 while some listed as 17x11. The difference is the direction of the grain. 3. The dimensions of paper are very humidity dependant. Paper fibers used to be a living thing and still act like living things: when they absorb water, it expands mostly against the grain direction. It's like a guy drinking beer: he doesn't get taller by drinking beer, only faster. Same thing with paper fibers. 4. Tadashi-san rocks.

[@FlumenSanctiViti]

Toilet paper - humanity's greatest invention! Could you just imagine a world without it?

[@neropatti1504]

Tadashi and James Grime rock my world. More, plz!

[@DrRiq]

I watch this guy before I go to parties so I can do cool party tricks jk i have no friends 😢

[@dusandusan4611]

Tadashi kills it every time!

[@vancewade6251]

This is more material science than anything but I don't mind one bit because Tadashi is the best.

[@sigurjonmyrdal3873]

Tadashi - absolutely brilliant and entertaining.

[@fenderify1592]

I totally relate to the bit at the end where he tears the toilet paper in a specific direction, i do that every time i have to pop a pimple :D

[@shawnsmith1865]

I like how he takes the simplest things and make them Einsteinishly interesting!!

[@Pengochan]

The reason toilet paper is easier to rip lengthwise is because that's the direction it runs in the paper machine, to have it the other way the machines width would have to be the length of the unrolled roll of paper.

[@HotelPapa100]

The direction of anisotropy of toilet paper actually is not deliberately chosen. It is a result of the manufacturing process which produces a sheet of virtually endless length and limited width. So if you want to produce a roll you are not free which direction of "grain" to use. The grain of paper always runs along the direction of manufacturing. Single sheets are normally cut so the grain runs along the long edge.

[@TimJohnson69]

excellent explanation and demonstration

[@chillsahoy2640]

So you're getting...Smarter Every Day? Anyway, I'd never thought this much about paper before but it really is quite a fascinating material once you look into its properties. We take it for granted that it works the way we want it to.

[@manrajdhanda]

Absolutely wonderful video! One of my favourites

[@mcsoloo]

tadashi rules! more videos plz!!

[@BillM1960]

He never ceases to amaze me.

[@SecretofTerra]

Really enjoyed it, especially the bit with calligraphy!

[@fattyzhang1995]

my mind is so blown right now.... I may never recover from this

[@CristiNeagu]

Learning solutions to problems we never knew we had. Engineering...

[@42scientist]

Exactly...

[@amyloriley]

Well, it was a problem once in history. Then they solved it. Now they pass on the knowledge to you, should you want to make your own brand of toilet paper.

[@urble]

man i love maths and science

[@macazu75]

imteresante...otro punto bastante interesante de Numberphile...les agradezco compartir estos "poco observables pero muy matematicos detalles cotidianos" . Muchas gracias.

[@davidmyers5224]

tadashi is awesome. I love videos with him

[@TheTombot]

Tadashi, you impress me all the time!

[@dermaniac5205]

*talks about tearing toilet paper* - "Every day I become a little smarter" He's so cute :-D

[@OriginalPiMan]

I think that toilet paper thing was explained backwards. I suspect that perforations were originally added to toilet paper to allow straight tears, rather than straight tears being prevented to encourage it to tear along the perforations. That toilet paper almost always goes that direction makes sense, once you connect that information to the earlier statement that the direction is caused by the manufacturing process (specifically the rolling).

[@drummer265]

I love every video with him.

[@JustinKoenigSilica]

well done and well animated! Neat trick.