World's Roundest Object!

The world's roundest object helps solve the longest running problem in measurement -- how to define the kilogram.
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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

Видео загрузил: Veritasium

Просмотров: 20445153
Добавлено: 4 года назад
Длительность: 11:44
Комментарии: 29729

Тэги для этого Видео:veritasium  science  physics  Perfect  sphere  kilogram  avogadro  avogadro project  redefining the kilogram  kilo  metric system  silicon  silicon sphere  silicon-28  silicon 28  watt balance  bipm  history of the kilogram  grave  units  SI units  definition  gram  mass  quantity  weight  weights  kilograms  csiro  kilogram of the archives  kilogramme  definition of the kilogram  unit  perfect sphere  roundest object  world's roundest object  kilogram definition  

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Steve PantsSteve Pants (36 минут назад)
From a round object
To SI Units
To Kilograms
To Water
To platinum stuff

Munjee SyedMunjee Syed (4 часа назад)
still no change to the kilogram definition but we are on the cusp of change

i_meow_sometimes GD - Guides - And more!i_meow_sometimes GD - Guides - And more! (14 часов назад)
Looks like you aren't even turning it!

Bogdan-Laurentiu BaltaretuBogdan-Laurentiu Baltaretu (16 часов назад)
Good thing the French didn't patented the SIU, otherwise it would have been SId'U, haha :D just kidding, love you all

Juma sayehJuma sayeh (17 часов назад)
just return to the original 1 liter of water at 4C degrees, here problem solved , now hand me my $1M.

SN1PERyanSN1PERyan (18 часов назад)
i would drop it like it's hot

Simon RileySimon Riley (1 день назад)
Well that makes it 3 roundest spheres in the world. The other 2 are in my pants

Is the kilogram unity already defined?

Carlos SotoCarlos Soto (1 день назад)
her body language was very obvious. lol

Nikhil SharmaNikhil Sharma (1 день назад)
1 million Euros! Could have been spent on saving millions of starving animals around the world.

Vedika BhatnagarVedika Bhatnagar (2 дня назад)
lol iMovie sound effects at grave

joe564338joe564338 (2 дня назад)

HotelPapa100HotelPapa100 (2 дня назад)

DemiTapDemiTap (2 дня назад)
the ftl soundtrack <3

Gamester 187Gamester 187 (2 дня назад)
Who else is watching this on Saturday, May 20, 2017

absolute madmanabsolute madman (2 дня назад)
Guy is overreacting. Sure, it's the roundest object in the world, but you wouldn't actually feel the difference between that and a regular object that was made to be round without the most scientific procedures in the world.

Radek PavlůRadek Pavlů (3 дня назад)
smoke weed everyday :-)

Radek PavlůRadek Pavlů (3 дня назад)
4:20 man :-) totaly stoned

clark hallclark hall (3 дня назад)
Can I hold it. That what's she said!

Zane RaymondZane Raymond (3 дня назад)
is he holding 1 of the big k's?

Gentel NooberGentel Noober (3 дня назад)
a sphere with r = x is rounder

I_Am_ ClickBate_I_Am_ ClickBate_ (3 дня назад)
That's pretty round.

Abbe ChannelAbbe Channel (3 дня назад)
I don't want it I don't wan't it...I WANT IT!!!!

eric311eric311 (3 дня назад)
You can cut the sexual tension with a knife

TWOW BookTWOW Book (4 дня назад)
That ball... I WANT IT

Jared LetoJared Leto (4 дня назад)
Why ?
Because they can :P
Basic answer for every science stuff ;)

Dracowhalelizard ShundarethornDracowhalelizard Shundarethorn (4 дня назад)
it's spherical, SPHERICAL

antibadism 4antibadism 4 (4 дня назад)
close ur eyes at start.

James StephensonJames Stephenson (4 дня назад)
still have no idea why people dislike these videos...

*Dragonhearted**Dragonhearted* (4 дня назад)

Ali SyedAli Syed (4 дня назад)
The guardian of the round object was flirting with Derek

G. LegendG. Legend (5 дней назад)
Veritasium - Active version of Vsauces

Bozidar DimitrijevicBozidar Dimitrijevic (5 дней назад)
wait how is the kilogram the only unit with a prefix?
there is microgram, nanogram and dekagram too.
please explain.

Mriganka Shekhar SarmahMriganka Shekhar Sarmah (5 дней назад)
That sphere deserves to be touched with the naked hands

SuperCityGamersSuperCityGamers (5 дней назад)
how can something be the roundest thing

ShakeITyEAShakeITyEA (6 дней назад)
"it contains only 1 atom and taht explains why it was so expensive!" no it doesnt, I still dont know

Pfod TakemPfod Takem (6 дней назад)
2:15 : The painting (Liberty leading the People by Delacroix) depicts the July Revolution of 1830, not the "French Revolution" of 1789

Crea SiryCrea Siry (6 дней назад)

Nenad BogoevskiNenad Bogoevski (6 дней назад)
Im trying to imagine the processing power that's needed for making 3D model replica... I mean... This can't be done on home computer? @Veritasium ?

Keven GilKeven Gil (6 дней назад)
I don't get it. If the highest point and the lowest valley would be 14 meters apart

Keven GilKeven Gil (6 дней назад)
I don't get it. If the highest point and the lowest valley would be 14 meters apart

Keven GilKeven Gil (6 дней назад)
I don't get it. If the highest point and the lowest valley would be 14 meters apart

fas.hfas.h (6 дней назад)
Veritasium : "by using a Watt Balance."

Me : "a what?"

SoraSora (7 дней назад)
Her: "Be careful!"
Me: Don't worry, I've got this.
*Drops sphere*

hemendrabhardwajhemendrabhardwaj (7 дней назад)
wouldn't redefining Avogadro number make the chemistry calculations difficult?

Kyo AniKyo Ani (7 дней назад)
would ufgg the hell outta that big titted milf

Dave The DuckDave The Duck (7 дней назад)
So you're telling me I can sharpen a pencil, say it way exactly a "ducktron" and I've basically got the only thing in the world to way a ducktron? Doesn't this whole thing rule out the weight system?

Mike S.Mike S. (7 дней назад)
after watching the new video with the soon to be defunct cylinders, DEREK ARE YOU HUNGOVER IN THIS HOLY SHI LOOK AT YOUR EYES

GMD DeathAngelGMD DeathAngel (7 дней назад)
The roundest object in the world is Vsauce's head.

Kevin ChenKevin Chen (8 дней назад)
is this video 18+? because I believe I saw boobs and nipples

DRS PresentsDRS Presents (8 дней назад)
Why do they assume the weight of Si atoms to be same forever?

DRS PresentsDRS Presents (8 дней назад)
Why don't they measure the weight of a 10kg Dumbbell and then divide it by 10.

Ayushman RanaAyushman Rana (2 дня назад)
DRS Presents r u retarded

Fast ErFast Er (8 дней назад)

Phillip AdamsPhillip Adams (8 дней назад)
Water is the proper choice of substances on earth. it is earth. it is you. and me.

josip bačanekjosip bačanek (8 дней назад)
would her touch my moshroom heded organ? :)

victorthegroovervictorthegroover (8 дней назад)
I like her :/

OnlyLogicOnlyLogic (8 дней назад)
"As early as 2014."
*Releases a new video*
"As of 2018..."
What took them so long?

D.Carlos FernadoD.Carlos Fernado (9 дней назад)
not in minecraft

HesseJamezHesseJamez (9 дней назад)
Germans use to say "Kilo" instead of "kilogramm(e), but that's for weight only!
A kilo-meter remains a kilometer.

Three LuiThree Lui (9 дней назад)
Lol people are shipping him and the sphere lady ahahahaha 😂😂😂😂

Gabriel HerreraGabriel Herrera (9 дней назад)
I found my next shift knob.

Water BuffaloWater Buffalo (9 дней назад)
1:23 cus y not?

Merlin PenderagonMerlin Penderagon (10 дней назад)
Let's see what happens if he drops it

Anwar RazinAnwar Razin (10 дней назад)
that thing is more perfect than my life

HDXFHHDXFH (11 дней назад)
Aussie dollars, why euros

HDXFHHDXFH (11 дней назад)

Lucas Castro OliveiraLucas Castro Oliveira (11 дней назад)
I got a little bit confused though. By using a sphere and using it's volume to calculate the atoms wouldn't it be highly prone to error because an irrational number(pi) is being used and we don't have any means to determine its full digits ?!

Vince LombardiVince Lombardi (11 дней назад)
The Aussie slipped out at ''otherwise basically"

Golden FreddyGolden Freddy (11 дней назад)
She looks so happy because she knows if that guy really wanted to he could grab that sphere and throw it straight to the ground, completely undoing countless hours of resource gathering and diameter testing and reshaping. So yeah, best to stay on his good side.

gabriel guerragabriel guerra (11 дней назад)
It's Spherical

WeiYuan WangWeiYuan Wang (11 дней назад)
I thought silicon atom is also a physical object...

OrgnolfOrgnolf (11 дней назад)
My left ear is very informed.

Arcane TurbulenceArcane Turbulence (11 дней назад)
"Each was carefully washed before their weigh-in" something changed their weight by micrograms.. but we don't know what... DERP

Armendii IbrahimiiArmendii Ibrahimii (11 дней назад)
if this was made on 2017 it would probably be just the first part of the video and IT WOULD have GONE WRONG GONE SEXUAL In the title

DeathbrewerDeathbrewer (12 дней назад)
I know the Earth isn't a perfect sphere (it's slightly oblong due to its own spinning/gravitational effects) but I heard the Earth itself, in terms of *smoothness*, if it were the same size as a pool cue ball, is more perfectly smooth than a pool cue ball, more smooth than ANYTHING we can make down here on Earth itself. Even counting the height differentials between Marinas Trench and Mt. Everest STILL is smoother than a pool ball if the Earth were the same size. Pretty insane how even the most "extremes" heights or depths we known of on the Earth are still so insignificant in relative terms of the entire Earth's size.

Lim Zheng HaurLim Zheng Haur (12 дней назад)
rewatched this because of the new video of the american kilogram

GutenGuten (12 дней назад)
you can pick up nerdy women with science

jake O'Shaughnessyjake O'Shaughnessy (12 дней назад)
If we were going to define a kilogram by a concept, why not use the old one of a liter of water at its most dense state

Nicolas ConchaNicolas Concha (12 дней назад)
others channels claim to the sharpest knife ever, the hottest something ever, the heaviest thing ever, but this is the only channel people can trust, World's roundest object? Awesome, that's the world's roundest object!

jacob hanndjacob hannd (12 дней назад)
I just came here to look at the worlds roundest object man...

B1ack 5niperB1ack 5niper (12 дней назад)
watt balance!!!

Shaco CloneShaco Clone (12 дней назад)
He should've got a cheap replica of it and drop it on the ground to mess with the people on YouTube..

Tigatron08Tigatron08 (12 дней назад)
This dude is hot

Dr. DonglepussDr. Donglepuss (12 дней назад)
What a nerd

Lou MinadiLou Minadi (12 дней назад)
So why did it take until 2018 for them to make the change?

BlueFlame414BlueFlame414 (12 дней назад)
dis boi wants to be vsauce

VoloundVolound (12 дней назад)
typo in the description - national "measurment" institute.

unijabnx2000unijabnx2000 (12 дней назад)
But North America did adobt SI units... we just convert from it.

Tushar AggarwalTushar Aggarwal (12 дней назад)
will be defined like this

Pete PetersenPete Petersen (12 дней назад)
Hey, Veritasium: If you spun this "roundest" object fast enough, could it affect the reflection? Could the light bouncing off of the object be altered by the speed of its surface in rotation?

CoolAsFreyaCoolAsFreya (12 дней назад)
UPDATE: in 2018 the kilogram will specifically be redefined

JDJD (12 дней назад)
The only country in Latin America with a copy is Mexico and also North Korea has one

YsheishYsheish (12 дней назад)
Liked how the music is Danse Macabre of Saint-Saëns when speaking about grave...

Ahmed HassanAhmed Hassan (12 дней назад)
Imma go there and replace it with a fushigi

Raul MartinaRaul Martina (12 дней назад)
You can't have a unit wich change its value over time.. wrong what's with money!

Slim_Shaddy112Slim_Shaddy112 (12 дней назад)
*hold the sphere* "wow it feels incredible" c'mon dude it's just a small ball

moo.moo. (12 дней назад)
I was about to ask why Si 28, but then I googled the answer.


iwanabanaiwanabana (12 дней назад)
and they were all like just spitting on it as they speak...!

Nihad AsadovNihad Asadov (12 дней назад)
Would bang her

Vibhor RawalVibhor Rawal (12 дней назад)
Anyone from his latest American kilogram video???

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