World's Roundest Object!

  • Опубликовано: 25 мар 2013
  • The world's roundest object helps solve the longest running problem in measurement -- how to define the kilogram.
    Support Veritasium on Patreon:
    A kilogram isn't what it used to be. Literally. The original name for it was the 'grave', proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK.
    But the problem with this definition has long been apparent. The IPK doesn't seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram's dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance.
    The Avogadro project aims to redefine Avogadro's constant (currently defined by the kilogram -- the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro's constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro's constant.
    Special thanks to Katie Green, Dr. David Farrant, the CSIRO, and the National Measurment Institute for their help. Thanks also to Nessy Hill for filming and reviewing earlier drafts of this video.
    There is debate as to whether this is truly the roundest object ever created. The Gravity Probe-B rotors are also spherical with very low tolerances such that they may in fact be rounder.
    Music by Kevin McLeod ( Decision, Danse Macabre, Scissors

Комментарии • 33 092

  • Jacob Pedersen
    Jacob Pedersen 2 часа назад

    why is his face so close to the screen

  • dhruv jain
    dhruv jain День назад

    Its 2018 and the definition still hasn't changed.

  • Jacob Bobst
    Jacob Bobst День назад

    your face is too close to the cam. zoom out or step back. its abrasive.

  • Heipit
    Heipit День назад

    have that same for 10€ from china ;^^

  • Noor Khan
    Noor Khan День назад

    Animation is the best way to promote your business, check out best animator here #Whiteboard_animations #Hand_Drawn #Professional_animation #Fiverr #fiverr_gigs #High_quality #Animation_video

  • Sultan Elshirazi
    Sultan Elshirazi 2 дня назад

    I am tired watching a video about kilogram

  • flashkraft
    flashkraft 2 дня назад

    A Palantir is a dangerous tool. The seeing stones are not all accounted for, you don't know who else is watching.

  • Blockistic
    Blockistic 2 дня назад

    it's 2018... and apparently this isn't put into practice yet? Why?

  • Ram Karmur
    Ram Karmur 3 дня назад

    Lol.. yesterday i throwed it away because I didn't know the actual price

  • thematthewchannel
    thematthewchannel 3 дня назад’s round?

  • The Dude
    The Dude 3 дня назад

    You most have never seen Kendra Lusts ass. 🤤🤤🍆

  • Camelworks
    Camelworks 4 дня назад

    Roundest object in the world? What about Karl Pilkington's head?

  • yoyohe2006
    yoyohe2006 4 дня назад

    Oh wow omg it’s a sphere wow

  • Crepper G
    Crepper G 4 дня назад

    She got some big ones

  • Crepper G
    Crepper G 4 дня назад

    *drops it*

  • Markus g
    Markus g 4 дня назад

    The mass was greater because the earth gains mass daily therefor creating stronger gravity. The sphere will also become heavier. Or a change in plate tectonics.

  • Pietro Tettamanti
    Pietro Tettamanti 4 дня назад

    Awesome! Thank you!

  • s a d b o i 。
    s a d b o i 。 4 дня назад +1

    What if it's the device they used to measure the weight of the kilogram is at fault? The kilogram was preserved and untouched for years, what about the device used to measure it? It has to be literally the same with the one they used years ago too. I mean it was only a one fingerprint difference...that kind of change close to nothing.

  • Blair Myers
    Blair Myers 5 дней назад

    Cool cannonball

  • Mr. 2006
    Mr. 2006 5 дней назад

    Video ends at 1:22. You're welcome.

  • Cedaelic VR
    Cedaelic VR 5 дней назад

    wow a ball

  • WonderfulFilms
    WonderfulFilms 5 дней назад

    Milligrams, anyone?

  • Tomas Robinson
    Tomas Robinson 5 дней назад

    The Ultimate Fushigi Ball.

  • Yasiru Ranaweera
    Yasiru Ranaweera 6 дней назад

    Is it feel like 10kg ? 😂😂😂


    The way they laugh to each other. Oh god that's awkward.

  • Luke Tremble
    Luke Tremble 6 дней назад

    Kilogram hahaha,changing mass hahaha fake news

  • GalactiNaut
    GalactiNaut 6 дней назад

    Ok, the quick fact that water is most dense at 4 C is really baking my noodle.....yay hydrogen bonding :D

  • Nightmare Fuel
    Nightmare Fuel 7 дней назад +2

    My left ear is enlightened

  • Future II GSU
    Future II GSU 7 дней назад

    Did they wash them with deionised water or just tap water?

  • VegetaPixel
    VegetaPixel 7 дней назад

    6:50 sick roast.

  • GD SmashBEAST
    GD SmashBEAST 7 дней назад

    That shiny ball doesn’t look to smooth...
    Oh wait that’s cause i had 144p nevermind.

  • Splarff
    Splarff 7 дней назад +1

    my left ear loved it

  • Touche
    Touche 7 дней назад

    The earth is more round than you would expect. If the earth was in the scale of that ball, you would not even be able to feel mount everest

  • acridPaladin
    acridPaladin 8 дней назад

    That was..... unexpectedly interesting to watch.

  • AbelMoua
    AbelMoua 8 дней назад

    People say there balls are rounder than that.

  • Tian Wang
    Tian Wang 8 дней назад

    th3 earth isnt round, its a eggish potato shape.... ish...

  • Richard Gates
    Richard Gates 8 дней назад

    Well, the machinery used to measure the sphere isn't perfectly round.

  • noah hernandez
    noah hernandez 8 дней назад

    Who in 2018

  • DGalacticMan
    DGalacticMan 8 дней назад

    Why the actual f*ck does this exist? What's it's purpose?

  • Sharp Tube JIM
    Sharp Tube JIM 9 дней назад

    That's what she said .

  • this channel has been terminated.
    this channel has been terminated. 9 дней назад

    I thought it was Winnie the Pooh..

  • Beckett Whidden
    Beckett Whidden 9 дней назад

    put it on 144p not round!

  • okay okay
    okay okay 9 дней назад

    People see me: EEWW
    People see the ball: I SHOULD MARRY THIS!

  • okay okay
    okay okay 9 дней назад

    Shipper: BUT WE'VE ALREADY GOT 3.1415926535897932384626433832795028841!!!!

  • TheRandomVideo Maker
    TheRandomVideo Maker 10 дней назад

    *C I R C L E S*

  • Trickspace
    Trickspace 10 дней назад

    I would love to kick it and lick it

  • Trickspace
    Trickspace 10 дней назад

    Nuts are rounder lol

  • 김도원
    김도원 10 дней назад

    Lol. How different could it feel from a regular non-perfect spheres that we see everyday? Humans are not sensitive enough to notice the difference.

  • Yarwin
    Yarwin 11 дней назад

    The mass of these kg units are not necessarily changed, but their electric charge is.

  • Flicky32
    Flicky32 11 дней назад

    That would be really funny to have taken a chip off of all of them.

  • epicpolyphony
    epicpolyphony 11 дней назад

    Any update on this?

  • digitalradiohacker
    digitalradiohacker 11 дней назад +1

    Velcome to the hydraulic press channel,
    Here we have a m'etul balle, it is extremely dangerous, and could attack at any time.
    So.. ve must deal vith it.


  • Bombastus
    Bombastus 11 дней назад

    isn't huge planets rounder

  • Jyothi Padakanti
    Jyothi Padakanti 12 дней назад

    it's just dumb
    everyone would accept that

  • Jyothi Padakanti
    Jyothi Padakanti 12 дней назад

    it's just dumb
    everyone would accept that

  • the classic lover
    the classic lover 12 дней назад

    Perfectly explained

  • Jason C.
    Jason C. 12 дней назад

    This is metrology. A science most people have never even heard of.

  • Lee
    Lee 12 дней назад

    can we please shoot some lasers into it, hit it with the full spectrum, lol

  • awsomeguy305
    awsomeguy305 12 дней назад

    its 2018 and i still dont know if this is a thing

  • rat soup
    rat soup 12 дней назад

    *accidental scratch*

  • Pseudo Nym
    Pseudo Nym 12 дней назад

    I need to investigate her orbs

  • Pseudo Nym
    Pseudo Nym 12 дней назад

    Weight changes of the mass where the mass is on earth too since the earth is an oblate spheroid.

  • King Levaithan
    King Levaithan 12 дней назад

    How round can it get?

  • Adrian Contreras
    Adrian Contreras 12 дней назад

    5 years later

  • Mirklav Hendrix
    Mirklav Hendrix 12 дней назад

    am i the only one who's seeing dimples and bumps on the "roundest" object in the world ? :D

    OÄKTA DOPBOK 12 дней назад

    "I promise I'll be careful." Immediately giggles and is not careful.

  • Dani Paunov
    Dani Paunov 12 дней назад

    If a pound is precisely 0.45359237 kilograms, then it is defined by a physical object, because the kilogram is

  • Aru • dev
    Aru • dev 12 дней назад

    Did you know?
    A sphere is round.

  • Just some satanist.
    Just some satanist. 13 дней назад

    Roundest object? You mean nicki minaj's ass?

  • Captain Yoshi
    Captain Yoshi 13 дней назад

    Aren't you that corespondent Derek muller guy from bill nye?

  • Kelly Pagano
    Kelly Pagano 13 дней назад

    So they made that thing with a bowling ball spinner?

  • AsianTastic
    AsianTastic 13 дней назад +1

    World's squarest object?

  • Roy
    Roy 13 дней назад

    Ur face is too close to the camera

  • David Panić
    David Panić 13 дней назад

    What's wrong with the definition of 1kg = 1l of water at 0°C in a vacuum? That's the original definition, why is it being changed?

  • Phoenix xox
    Phoenix xox 13 дней назад +1

    I wanna throw it into a wall

  • Arch Solphire
    Arch Solphire 13 дней назад

    Correction, conversion defines it as 0.45359237 kilograms. The same could be used in reverse. Your insult attempt is invalid, thanks to perspective.

  • Tatboy31 Schwartz
    Tatboy31 Schwartz 14 дней назад +1

    I have two very round balls

  • Gabriël van Dijk
    Gabriël van Dijk 14 дней назад

    why would you spend so much for something like that? its a freakin round baal. get a marble if it facinates you so much you wont notice the difference

  • Mirza Shanawaz
    Mirza Shanawaz 14 дней назад

    Mind blown

  • Dominik Černý
    Dominik Černý 14 дней назад

    Oooooooooooooooh the ball

  • Julian Hans
    Julian Hans 14 дней назад

    Hey! vsauce: michael here

  • Live with kittys Kittys are cool
    Live with kittys Kittys are cool 14 дней назад +1

    The main English units are the pound and ounce for weight.

  • cough cough
    cough cough 14 дней назад


  • StormzSR
    StormzSR 14 дней назад

    Republican governments are always coming up with the best inventions!

  • TomatoTime
    TomatoTime 14 дней назад

    Bitch it aint happening

  • Songs and Stuff
    Songs and Stuff 14 дней назад

    So, it’s a ball of metal?

  • StefannoTheConqueror
    StefannoTheConqueror 14 дней назад

    N = n x Na

  • Pat Westerman
    Pat Westerman 14 дней назад


  • Valtteri Laiho
    Valtteri Laiho 14 дней назад

    this video was way deeper than i was expecting damn

  • waleed khan
    waleed khan 14 дней назад

    good shot broh

  • capsaicin
    capsaicin 14 дней назад

    Careful. It's also a dormant palantír awaiting Sauron's return.

  • Ryan J
    Ryan J 14 дней назад +1

    1:06 dude whaaat

  • LexBlack1983
    LexBlack1983 15 дней назад

    She wants the D, man, she wants the D

  • TheDeeTV
    TheDeeTV 15 дней назад

    So basically a kilogram is a liter of water in 4 degrees plus a grain of rice

  • Pierre The Hypebeast
    Pierre The Hypebeast 15 дней назад +2

    0:35 "It feels...


  • Galactic Wolf
    Galactic Wolf 15 дней назад

    1:23 Imagine if the video just ends right there

  • Hunter Irby
    Hunter Irby 15 дней назад


  • samuelsson sanchez
    samuelsson sanchez 15 дней назад

    you look sleepy

  • UnluckyGuy
    UnluckyGuy 15 дней назад +1


  • onzkicg
    onzkicg 15 дней назад

    Lol.. coming from series of prank clips.. i don’t know why i stayed until end but thanks anyway, at least I found something interesting & sensible in RUclip. ;)