Stable Rollers - Numberphile

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  • Опубліковано 28 сер 2024
  • Tadashi Tokieda is back. This time talking about stability, instability and train wheels.
    More Tadashi videos: bit.ly/tadashi_...
    Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): bit.ly/MSRINumb...
    We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science.
    NUMBERPHILE
    Website: www.numberphile...
    Numberphile on Facebook: / numberphile
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    Subscribe: bit.ly/Numberph...
    Videos by Brady Haran
    Editing and animation in the is video by Pete McPartlan
    Patreon: / numberphile
    Brady's videos subreddit: / bradyharan
    Brady's latest videos across all channels: www.bradyharanb...
    Sign up for (occasional) emails: eepurl.com/YdjL9
    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 UA-cam 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

КОМЕНТАРІ • 668

  • @WouterWeggelaar
    @WouterWeggelaar 7 років тому +635

    I love how Brady addressed the elephant in the room about the cups being connected, and he obviously knew the answer but it was the right question to ask. Video Journalism at its best!

    • @numberphile
      @numberphile  7 років тому +257

      ;)

    • @tazzadk8363
      @tazzadk8363 7 років тому +6

      Wasn't it obvious they're connected?

    • @TwaritWaikar
      @TwaritWaikar 7 років тому +13

      Everyone can't see the same things to be obvious as you. That's why journalism is a thing

    • @frechjo
      @frechjo 7 років тому +31

      Ah yes, that was a great touch.
      It takes character to identify yourself with the part of the audience that didn't see it, and resign a chance to look smarter.
      It takes ability to spot a point that might seem obvious to many, but in the hundreds of thousands of views this videos get, many people will benefit from a clarification.

    • @tazzadk8363
      @tazzadk8363 7 років тому +2

      i find this comment to be very true after watching alot more of his videos. i guess i missed the obvious! lol

  • @NothingYouknow96
    @NothingYouknow96 7 років тому +233

    This guy is the king of explaining complicated stuff with simple things.

    • @freshrockpapa-e7799
      @freshrockpapa-e7799 7 років тому +13

      Stability isn't complicated stuff though.

    • @umchoyka
      @umchoyka 7 років тому +40

      +Fresh Rock Papa-E HAHAHAH
      - Me, Control Systems Engineer.

    •  7 років тому +1

      +Fresh Rock Papa-E
      I think that pretty much every engineer or physicist will have a different opinion on that. *A lot* of time in engineering and physics is spent studying stability-related issues, be it turbulence, (self)-resonance, decays, and tons of other stuff that are very relevant to pretty much anything we do.

    • @siblinganon66
      @siblinganon66 7 років тому

      Mikkel Højbak you can add atomic bonds to that list, too. whenever there are two opposing forces linked to the same dimension you got a stabilizing system.

    • @freshrockpapa-e7799
      @freshrockpapa-e7799 7 років тому +2

      Of course it can be very complicated. But the concept and this particular example isn't. You clearly understood what I meant, if you could stop boasting at every opportunity about you being an engineer your profession would have more respect.

  • @RealEngineering
    @RealEngineering 7 років тому +229

    Dihedral and anhedral wings are a really interesting example of this in wings.

    • @RancidPrune
      @RancidPrune 7 років тому +3

      That's true to some extent, but doesn't mean that dihedral = stable and anhedral = unstable. High-wing aircraft like the Airbus A400M or AN-225 use anhedral angle wings due to the relative position from the centre of mass.

    • @etherealstars5766
      @etherealstars5766 7 років тому

      RoninTuah Lol yeah, AN 225 largest plane in the world

    • @danteregianifreitas6461
      @danteregianifreitas6461 7 років тому +6

      +Real Engineering wow, you around here? what an epic crossover! pls make a vid about those wings

    • @RancidPrune
      @RancidPrune 7 років тому +4

      dothemathright 1111: Yeah I don't know where you got that from, you certainly weren't in my aero engineering courses at uni. Just a quick search on wikipedia and I found this:
      "Anhedral angles are also seen on aircraft with a high mounted wing, such as the very large Antonov An-124 and Lockheed Galaxy cargo aircraft. In such designs, the high mounted wing is above the aircraft's center of gravity which confers extra dihedral effect due to the pendulum effect (also called the keel effect) and so additional dihedral angle is often not required. Such designs can have excessive dihedral effect and so be excessively stable in the spiral mode, so anhedral angle on the wing is added to cancel out some of the dihedral effect so that the aircraft can be more easily maneuvered."
      So yes, centre of mass is sometimes a primary concern, especially for larger aircraft.

    • @RealEngineering
      @RealEngineering 7 років тому +11

      RoninTuah true, but it's not a true comparison. Low wing with anhedral would absolutely be unstable. High wing planes like the AN-255 need anhedral wings, as the lower centre of gravity makes rolling more difficult (more stable). The anhedral wing introduces instability to allow roll with less effort.

  • @Lornda
    @Lornda 7 років тому +131

    this episode was off the rails!

    • @OrangeC7
      @OrangeC7 3 роки тому +3

      Actually, only half of it was. The other half was a stable mechanism. ;)

  • @jonahlee8894
    @jonahlee8894 7 років тому +659

    7:12 it is near impossible to get it to roll all the way down *does it first try.
    Kendama
    without spinning the ball, it is near impossible to get the ball on the spike *does it first try

    • @OrangeC7
      @OrangeC7 7 років тому +75

      ...there seems to be something special about Tadashi. ;D

    • @teeds88
      @teeds88 7 років тому +56

      this guy's skill is insane. WAY over 9000 actually

    • @balthasarrasahtlab8872
      @balthasarrasahtlab8872 7 років тому +23

      Asians.

    • @alephnull4044
      @alephnull4044 7 років тому

      Balthasar's right lol.

    • @fishyeverything8530
      @fishyeverything8530 7 років тому +10

      Aleph Null I have a question?
      How big are you

  • @KalebPeters99
    @KalebPeters99 7 років тому +388

    I can't help but notice the go-pro that was set up, but from which we didn't get any footage... 🤔

    • @numberphile
      @numberphile  7 років тому +172

      +Kaleb Peters didn't end up needing it.

    • @baquirsayed4135
      @baquirsayed4135 7 років тому +30

      Legend says that numberphile responds if a person commented soon enough.

    • @TheVMDC
      @TheVMDC 7 років тому +1

      +Sphagetti Or try to forage a couple cups for yourself.

    • @fossilfighters101
      @fossilfighters101 7 років тому +2

      +

    • @KalebPeters99
      @KalebPeters99 7 років тому

      Numberphile Thought that would've been the case

  • @JafarChou
    @JafarChou 7 років тому +599

    Brady's gotten better at his animation :D

    • @JBergmansson
      @JBergmansson 7 років тому +25

      I'm not sure, but I think there's a studio that does Numberphile's animations, and not Brady all by himself.

    • @moritzgeusen3818
      @moritzgeusen3818 7 років тому +122

      i think the animation is by Pete McPartlan - at least it says so in the description

    • @TheHuntermj
      @TheHuntermj 7 років тому +314

      AbuJafar Choudhury
      I know, Tadashi looks so real...

    • @vincentpelletier57
      @vincentpelletier57 7 років тому +7

      Better than Tarkin did!

    • @etherealstars5766
      @etherealstars5766 7 років тому +2

      Matt Hunter Lol!

  • @Propulus
    @Propulus 7 років тому +35

    Tadashi is probably my favourite person here. I actually binge watch all the episodes with him from time to time. No video is sub par.

  • @almondtart
    @almondtart 7 років тому +8

    This guy, James Grime, Matt Parker, and the Klein bottle guy are my favourite presenters of all time.

  • @dancoulson6579
    @dancoulson6579 7 років тому +9

    I think Tadashi is my favorite guy from all numberphile presenters.
    Something about his personality, and way of explaining things is brilliant. I really want to see more and more of him.
    I like his voice too. Easy on the ears.

  • @anon8857
    @anon8857 7 років тому +64

    ma boi tadashi is back !!!

  • @timothymckane6362
    @timothymckane6362 7 років тому +33

    Tadashi is the Bob Ross of tinkering math toys.

  • @AngryArmadillo
    @AngryArmadillo 7 років тому +14

    This is also why many pulleys are "crowned" meaning they have a convex shape to allow the belt to automatically center itself.

    • @fahrenheit2101
      @fahrenheit2101 2 роки тому

      Ah, I've seen Steve Mould do a video on that phenomenon - I guess they are similar.

  • @papershark6266
    @papershark6266 7 років тому +2

    Tadashi is my favorite guest on numberphile. He explains things so clearly.

  • @xystem4701
    @xystem4701 7 років тому +21

    I already need more Tadashi!

  • @user10476
    @user10476 7 років тому +2018

    1 guy 4 cups is so much better than 2 girls 1 cup.

    • @pengin6035
      @pengin6035 7 років тому +22

      user10476 This will be topcomment

    • @KalebPeters99
      @KalebPeters99 7 років тому +69

      user10476 To be fair, almost all things are better than 2 girls 1 cup...

    • @bisantianr9405
      @bisantianr9405 7 років тому +5

      user10476 notice me, top comment guy !

    • @skydragon3857
      @skydragon3857 7 років тому +2

      I am a new guy who noticed you !

    • @user10476
      @user10476 7 років тому +2

      Ryz Random I notice you, regular comment guy!

  • @puupipo
    @puupipo 7 років тому +1

    I still remember when I learned about this concept of stability and instability in school in terms of negative and positive feedback loops. It didn't seem like much back then, but later on I've noticed that understanding that there are some systems where change creates more change and others that return to normal after a change is actually quite useful in everyday life.

  • @SandyBathwater
    @SandyBathwater 4 роки тому +2

    I "discovered" this a few years ago, I had an axle (stick) with wheels on the ends (plywood rectangles) and I was rolling it down 2 beams like in this video. I was using a very slight incline and a 1/8" axle with 6" wheels, rolling on the axle. (a very cool effect, btw). It tended to wander to one side or the other, and in a leap of genius (not really) I wrapped electrical tape around the axle inside of where it contacted the rails... My intention was just to block it from moving that far. What ended up happening was what happens in this video, when the tape went on the rail, the radius of the axle there was larger so covered more ground because the rotation speed was constant for the whole assembly, which turned it back on track. I must say it was fun puzzling out what was happening and very gratifying to have accidentally discovered it, knowing it was nothing new. The first guy to roll an old wine barrel down two rails probably felt the same way.

  • @Jet-Pack
    @Jet-Pack 7 років тому +158

    The X-Ray was funny haha

  • @superj1e2z6
    @superj1e2z6 7 років тому +117

    7:02
    Tadashi should have said _"Tadaaaa!"_

  • @IvanEedle
    @IvanEedle 7 років тому +3

    Love the animations, they have really improved over the last 6 months and become a great learning tool.

  • @anomalocaris540
    @anomalocaris540 7 років тому +3

    Tadashi, please publish a book with those activities. I would buy it in a heartbeat.

  • @DorthLous
    @DorthLous 7 років тому +1

    I love all people shown in this channel, but Tadashi Tokieda is pure gold.

  • @Edvardius
    @Edvardius 7 років тому +5

    I love how mr Tadashi translates how the world works in so simple words. :)

  • @YingwuUsagiri
    @YingwuUsagiri 7 років тому +2

    I love his playful approach at explaining things that you never think about like the trains.

  • @BobWestIsDead
    @BobWestIsDead 7 років тому +2

    Tadashi's videos are always my favorite

  • @TheDeetster
    @TheDeetster 7 років тому +1

    This guy is wonderful at explaining things to make them easy to understand

  • @Goryus
    @Goryus 7 років тому +1

    Tadashi's Toys is the best Numberphile series.

  • @yopyopyop77
    @yopyopyop77 7 років тому

    Mr. Tadashi Tokieda's videos are always my favorite Numberphile videos. Very clear, articulate and tangible !

  • @williamiannucci2740
    @williamiannucci2740 4 роки тому +1

    You are amazing !!! Thank you from Bill in the USA.

  • @Luxalpa
    @Luxalpa 7 років тому +1

    I was asking myself this question with the train wheels 15 years ago when I was a child and had model trains. Thanks for finally giving me an answer to it!!

  • @Terrados1337
    @Terrados1337 7 років тому

    Nothing brightens the day more than a nice cup of coffee and learning something new

  • @russabraira6979
    @russabraira6979 7 років тому +2

    The quickest I ever move is when spotting a new Tadashi video and clicking it

  • @brian122812
    @brian122812 7 років тому +3

    his laugh at the end of the video is so pure

  • @geckoman1011
    @geckoman1011 10 місяців тому +1

    We did this in high school physics. One of the many things I remember from that class

  • @NuclearRoll
    @NuclearRoll 7 років тому +1

    those lil numberphile guys in the animations are so adorable

  • @HeavyboxesDIYMaster
    @HeavyboxesDIYMaster 7 років тому +33

    As usual, he says it's almost impossible to roll it all the way down, then he does it.

    • @mathiasrryba
      @mathiasrryba 7 років тому +1

      That's the worst thing ever

    • @chriswebster24
      @chriswebster24 2 роки тому +1

      Yeah, he’s a liar and a show off. That’s why no one likes him and he has no friends.

  • @ProGangstaShit
    @ProGangstaShit 7 років тому +1

    Tadashi, togehter with Matt Parker, are my absolute fav vids

  • @SaveSoilSaveSoil
    @SaveSoilSaveSoil 3 роки тому

    Mind blowing! I am amazed by Prof. Tokieda's ability to find magical phenomena in seemingly mundane objects!

  • @maldoran9150
    @maldoran9150 7 років тому +1

    Mr. Tokieda videos are my absolute favorites, also great editing as always!

  • @GamersBar
    @GamersBar 7 років тому

    I really like Tadashi Tokieda , its clear he loves this stuff and its just small interesting stuff that most people would never think about.

  • @FalconBass
    @FalconBass 7 років тому +1

    His videos are so much fun! Thanks dr. Tokieda!

  • @cookiemonster3147
    @cookiemonster3147 7 років тому

    Allways a joy to watch this man.

  • @7markhunter
    @7markhunter 7 років тому

    this explains very nicely why the cogs on belt drives have a carefully chosen convex profile, the belt self corrects its alignment. very cool

  • @whitepointstarproductions8905
    @whitepointstarproductions8905 7 років тому

    Tadashi's videos are some of the most interesting on the channel

  • @beachboardfan9544
    @beachboardfan9544 7 років тому

    Graphic that starts at 3:50 is awesome, great sense of humor whoever is responsible for that!

  • @PromptedHawk
    @PromptedHawk 7 років тому

    Tadashi and Matt are definitely my favourites.

  • @kuronosan
    @kuronosan 7 років тому +1

    I can't double like this, can I? The mind-reading part was ... wow.

  • @archfiendize
    @archfiendize 7 років тому

    I seriously wish I had a teacher like this. So simple and so sublime! More of Tadashi please!!

  • @pedroscoponi4905
    @pedroscoponi4905 7 років тому +1

    That ending was the best! Clearly Tadashi's skills are not limited to Kendama, hehe XD

  • @orbik_fin
    @orbik_fin 7 років тому +5

    7:00 Tadashi: "I can do it anyway."

  • @zarporiko
    @zarporiko 7 років тому +1

    wow, I never knew trains were made in such a way, that's some incredible designing

  • @1n5uff1c13n7
    @1n5uff1c13n7 7 років тому

    That's a really smart solution to the skipping in corner issue for trains. I've never thought about it!

  • @YaStasDavydov
    @YaStasDavydov 7 років тому +1

    Whoever made those animations is a very nice person

  • @AnitaSV
    @AnitaSV 7 років тому +5

    I finally understood how trains work. Tadashi's videos must be mandatory educational material.

  • @deanc9195
    @deanc9195 7 років тому

    Tadashi is the best part of this channel

  • @realcygnus
    @realcygnus 7 років тому

    Love this Guy........he always demos such simple yet subtle & interesting ideas........Richard Feynman once mentioned in an interview.........that this was a question asked by his fraternity

  • @nO_d3N1AL
    @nO_d3N1AL 7 років тому

    It's amazing how this guy manages to make so many interesting observations primitive everyday objects; without even doing naything complicated. Great stuff

  • @adityaphanindra
    @adityaphanindra 7 років тому

    I love Tadashi's videos. Simple concepts very well explained. Keep them coming.

  • @0MVR_0
    @0MVR_0 7 років тому +1

    Whoever makes the 3D animations deserves so attention.

  • @JupitersDancer
    @JupitersDancer 7 років тому +2

    6:31 That 3D animation was soo smooth :D

  • @ErikOosterwal
    @ErikOosterwal 6 років тому

    This same principle is used on traction pulleys that used to be used on machinery. Instead of using V-groove pulleys they use pulleys that have a slight crown in the center of the track. When the belt that's stretched between two of these pulleys gets off center the crown pulls the belt back towards the center. This very important during the early industrial revolution because it was nearly impossible to make belts that were straight. They were usually made of one or more long leather straps sewn together; later they were sewn with a single twist, like a mobius strip, so that the belt would wear evenly across "both" sides.

  • @user-st6en6sh8q
    @user-st6en6sh8q 6 років тому

    Such a simple thing but when it's explained in such a nice way you realise it's not as simple as first thought

  • @mattarchbell
    @mattarchbell 5 років тому

    Tadashi makes my fav vids on this channel

  • @ikkylovesbass
    @ikkylovesbass 7 років тому

    Yay! Tadashi's videos are my favourite!

  • @dampierre99
    @dampierre99 7 років тому

    Learn something new everytime I watch your videos. Really great

  • @SapientPearwood
    @SapientPearwood 7 років тому

    I'm taking a stability class, and I really like my professor, but Tadashi is just excellent at teaching.

    • @mathiasrryba
      @mathiasrryba 7 років тому

      "I'm taking a stability class" I'm sorry but to me this sounds like if you had psychological problems lol ( I know what you mean, that's just the 1st thing that came up to my mind when I read your comment)

  • @JackPoint
    @JackPoint 7 років тому

    Such a wonderful explanation for a wonderful effect

  • @vinny142
    @vinny142 7 років тому

    I can listen to this man for Hours!

  • @TTaylor
    @TTaylor 7 років тому

    I used to do construction layout. Curves were no problem on roadways, but on railways they use spiral curves which I knew very little about. Now I understand why the spiral curve is necessary.

  • @Owl90
    @Owl90 7 років тому +1

    My mind was expanded.
    Thank you!

  • @tomlynd8836
    @tomlynd8836 7 років тому +1

    Thanks for such wonderful videos

  • @adnenmez
    @adnenmez 7 років тому

    The animation though.. I don't see people appreciating this amazing animtion

  • @lxathu
    @lxathu 7 років тому

    You just gotta love numberphile teachers. There's no escape, resistance is futile.

  • @eideticex
    @eideticex 7 років тому

    I now understand why certain bushings on cars are so prone to failure and it's directly a result of the rollers stability issue. It also occurs to me that a slight hammering to the brackets is all that's needed to extend the longevity of the bushings. Particularly with control arms where bushings aren't always a cylinder shape but more conical like the rollers. The reason I'm drawing this equivalence is the rolling motion that requires the bushing to be there is throwing it slightly off stability but with a ton or so of weight shoving down on it.

  • @donkeyfacekilla1
    @donkeyfacekilla1 7 років тому

    Love this guy. His videos are so interesting !

  • @shadrack1701
    @shadrack1701 7 років тому

    More Tadashi, love that guy.

  • @muizzsiddique
    @muizzsiddique 7 років тому

    I will always enjoy a Tadashi's Toys video.

  • @15october91
    @15october91 7 років тому +2

    I love this guy.

  • @squaremarco
    @squaremarco 5 років тому

    He even got the perfect roll with the unstable system at the end. What a man

  • @LegendaryKenneth
    @LegendaryKenneth 7 років тому

    Remember watching Feynman's talk on train wheels many years ago. Great stuff

  • @Fiddlesticks86
    @Fiddlesticks86 6 років тому

    Tadashi is so entertaining to watch! ✌

  • @erwanmoreau6357
    @erwanmoreau6357 5 років тому

    Thanks for this wonderful talk Prf. Tadashi !

  • @LeonardoAngel3000
    @LeonardoAngel3000 4 роки тому +1

    Awesome explanation, thanks

  • @harpalvaghela2798
    @harpalvaghela2798 2 роки тому

    Only Dr tadashi from numberphile team brings art to physics

  • @justanorang916
    @justanorang916 7 років тому

    Prof. Tokieda is a great teacher!

  • @Unknowngamer1138
    @Unknowngamer1138 7 років тому

    I remember seeing an interview with Feynman about this exact problem and I've gotta say, Tadashi does a much better job of explaining it.

  • @Scanlaid
    @Scanlaid 7 років тому

    I love Tadashi. I'd watch a whole TV series of him just explaining odd things.

  • @ArnavBarbaad
    @ArnavBarbaad 7 років тому +179

    Tadashi didn't use his foot in explanation. Unsubscribe

    • @MrRabix007
      @MrRabix007 7 років тому +3

      may be the part with his foot censured from youtube

  • @selmtron
    @selmtron 4 роки тому

    This is how a train takes turns, and self corrects. Also, when you lean a bike over, the radius in the middle of the tire is larger than the side knobs, creating a stabilizing turn.

  • @KieranGarland
    @KieranGarland 7 років тому

    A truly fascinating video. Thanks for sharing.

  • @CalvinHikes
    @CalvinHikes 7 років тому

    Man, this video was off the rails.

  • @quantumnaught
    @quantumnaught 7 років тому

    this is perfect for visual learners! love this guy!

  • @HaloInverse
    @HaloInverse 7 років тому

    This feels like it's connected to chaos theory - systems like double-rod pendulums where tiny deviations in initial conditions turn into huge deviations over time. The indication seems to be that, in general, chaotic systems could be stabilized by finding the element(s) that tend to amplify initial deviations and finding a way to "reverse their sign" or feed them back opposite to the deviation.

  • @pstrap1311
    @pstrap1311 6 років тому

    I had no idea that train wheels were rigidly affixed to their axle. Thanks for the knowledge!

  • @DeconvertedMan
    @DeconvertedMan 7 років тому

    I watched him give a talk with lots of toys with these included - want more! MORE toys!

  • @EdM66410
    @EdM66410 7 років тому

    I feel like tadashi spoke shorthand the whole video but I understood everything. Wild.

  • @ignaciot
    @ignaciot 7 років тому

    You´ve made my day with this vid.

  • @joshl90
    @joshl90 7 років тому +1

    A Tadashi video where his shoes and socks stay on? Mind blown

  • @prawtism
    @prawtism 7 років тому

    that rollercoaster animation was way too nice :D