Nobody's Exactly Sure How Much A Kilogram Is Right Now

Yes, it's only micrograms of difference, but it's still really weird: until 2018, the kilogram is defined as "the weight of this physical object". So what happens when that object changes?

and on Instagram and Snapchat as tomscottgo

[DuncanEllis]

a weighty issue with many opportunities for mass confusion.

[lukasu]

it depends if it's a kilogram of steel or a kilogram of feathers

[Jay_Bee_Beats]

So apparently the new kilogram standard is this -

"The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10-34 when expressed in the unit J s, which is equal to kg m2 s -1 , where the meter and the second are defined in terms of c and ∆νCs."

[PracticalEngineeringChannel]

I've got a watt-balance project in the works. Still working out the details.

[WhyDoesMyCodeNotCompile]

And today 16.11.2018 The vote to change the definition of the kilogram has offically and unanimously passed in paris. SI-Units will no longer depend on physical artifacts, just on the fundamental constants of nature. Praise Science

[peterdietrich]

I want a mission in GTA where you steal the kilogram and sell it back for millions.

[crumpetblogs]

nobody's exactly sure how much a pound is right now either

[slashpointo]

My local drug dealer linked me to this video after ripping me off. All makes sense now. What a nice guy

[OptimusPhillip]

I am from the future. The kilogram is now defined based on the Planck constant, which is absolute, universal, and has units of kilogram meters-squared per second. With the physically defined meter and second, this number can be used to define a kilogram.

[SurpriseCollector]

i hope they will make a bigger kilogram, then I will lose weight without dieting :)

[The_Horizon]

1:46 how did they get that photo without a camera in the reflection pointing it?

[SentinalKnight]

That sphere reminds me of vertasium's world's roundest object video....

[hugo-garcia]

Nobody exactly sure how much a kilogram is right now... Specially Americans

[AvailableUsernameTed]

"Operation Gram Slam, Mr. Bond is where my team of svelt cat burglars shave milligrams off *the* Kilogram thus increasing the amount of all my stuff. Ha ha!"
"But wouldn't that increase everyone's stuff equally, Gramfinger?"
"oh .. yeah."

[DJ_Dett]

I'm surprised we don't all use a unit of mass based on 1 MOL of pure water at its exact freezing point, or something else more definitive.

[puellanivis]

I worked for the Metrology Lab at NMSU it was pretty cool. It was kind of weird because we got a lot of shipments from all over New Mexico to validate their weight… it's kind of weird when it's like, “Package weight: 1 kg ± 5 µg”

Apparently, there's a set of weights that keeps getting posted around to the various state metrology labs and they weigh them and compare results. It was kind of cool. :)

[MPSpecial]

I briefly worked at the International Bureau of Weights and Measurements, at the masses department, I could have a glance at the Kibble scale, that machine made to correlate the kilogram to the Planck constant so we don't rely on standard masses anymore. That thing is so precise it can catch the gravitational gradient across the room. Heck it even has to take into account its own gravitational field in the computation. They put it in in a basement room after removing the floor, so it has no physical contact with the building.

[OblivionTube]

Is that the same sphere that Veritasium touched? =)

[flawbertrobert]

Man! So cool all the random stuff you do videos on. I also like when you get guests to chip in on their fields of expertise.

[LabaShabba]

Well explained tom. I find metrology is a subject people either click with instantly or just seem puzzled by the whole thing all together. Good concise explanations of some quite complicated information. NPL have excellent training information too so good to see they have a channel, thanks