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

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  • Published on: 27 June 2016
  • 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?

    Thank you to everyone at the National Physical Laboratory! You can visit them at http://npl.co.uk

    I'm at https://tomscott.com
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  • Runtime : 3:45
  • tomscott tom scott things you might not know kilogram national physical laboratory npl watt balance kilo silicon sphere silicon sphere relative si units

COMMENTS: 40

  • Nathan
    Nathan   5 days ago

    Yes but is it an African swallow???

  • Jaden CM
    Jaden CM   1 weeks ago

    What about distance measurements

  • DrHillbillyShow
    DrHillbillyShow   1 weeks ago

    The one in Paris gained a tiny amount of weight from a wine stain and cigarette ash.

  • Simorenarium
    Simorenarium   1 weeks ago

    Not anymore, the international Standard for the Kilogramm has been redefined

  • somekindofusername
    somekindofusername   2 weeks ago

    I don’t know how I got here but I feel a tiny bit smarter for watching this

  • Alex Rhinehart
    Alex Rhinehart   1 months ago

    I thought europeian measurments were defined by mathematical equations?

  • Nunovia Gottdamnedbizzness

    It's not a kilogram everywhere on Earth, isn't there a great deal of variation in gravity, such as the lower gravity found around Hudson's Bay in Canada? So nothing is an exact kilogram is it?

  • Rushika Prasad
    Rushika Prasad   1 months ago

    So did everyone forget the entire space station that blew up because the Americans built thier parts in inches, and everyone else used centimeters?

  • K3v1n
    K3v1n   1 months ago

    now it's defined by the boltzmann constant

  • The Ginger Power Ranger

    In America we use one pound of bananas which is exactly equivalent to one bottle of mouth wash or one basket of bread. It is very accurate.

  • hotelmario510
    hotelmario510   1 months ago

    Me, just now realising a kilogram is basically an arbitrary measurement: 🤯

  • Todd no last name
    Todd no last name   2 months ago

    Was the definition of a pound so complicated back when you used it? The reason the US doesn't use metric? Because the French created it, apparently. That's a good enough reason.

  • izare 99
    izare 99   2 months ago

    If you smash this will everything start floating?

  • AlexGRFan97
    AlexGRFan97   2 months ago

    I'm sorry, but isn't testing machines that have been tested against other machines in a generational chain an incredibly short-sighted way of maintaining accuracy? Let's say Machine A is tested against The Kilogram, and has a variance of less than a thousandth. Something like 1.00001 kg. Insanely accurate. However, it's not perfect, and when Machine B is calibrated so that Machine A's kilogram becomes its kilogram, it too possesses a variance, something like 1.00003 kg. After 100 generations of machines, what was once an almost exact kilogram has now veered into, I don't know, 1.01538 kg. Not a lot of difference at the small scale, but in a tonne that's over 15 phantom kilograms that don't exist. Surely there's a better way? Like making one master series of machines that all later machines are tested against?

  • Anita Leahy
    Anita Leahy   4 months ago

    Figure out a gramme weight in an inanimate, solid object, possibly a stone perhaps? Multilply, wait a year for results and then monitor consistently for however long to see if the weight of the French KIlogramme fluctuates?

  • Steve Jones
    Steve Jones   4 months ago

    I wish you wouldn't keep saying those weigh a kilogramme. The don't. A kilogramme is a unit of mass whilst weight is a force. I realise in everyday use, we use these terms interchangeably, but this is a video about an SI unit and it's important to get the terminology correct in that context. There is a sense in which electronic scales have to be calibrated against local gravitational fields and centripetal force so that they are, in effect, measure mass (balance scales do that automatically), but these things are standard masses, not standard weights.

  • Peter Berne
    Peter Berne   5 months ago

    I always thought that 1 litre of water weighed 1kg

  • IdleWorker
    IdleWorker   6 months ago

    Me stepping of my bathroom scale:- "... Well what is a kilogram anyway..?"

  • Thomas Walder
    Thomas Walder   7 months ago

    But is one of steel heavier than one of feathers?

  • sagjig2
    sagjig2   7 months ago

    I guess you could say this is an absolute unit.

  • Chris Wong
    Chris Wong   8 months ago

    It doesn't "matter". Good job sneaking a pun in there, Tom!

  • The Rolling General
    The Rolling General   9 months ago

    Finally we can say that a Kilogram of steel is heavier than a Kilogram of feathers.Because steel is heavier than feathers.

  • Samrit Kunja
    Samrit Kunja   10 months ago

    For the ones who want to know, scientists just disregarded this system and now have adopted an absolute value for the kilogram, similar to the Planck's constant.

  • Sinan
    Sinan   11 months ago

    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

  • Skipper Riddles
    Skipper Riddles   11 months ago

    We know how much a gram weighs. Kilo is a thousand, so what is difficult in the equation? 1000 grams.

  • Charlie K
    Charlie K   11 months ago

    1 Kg is the mass of the international kilogram prototype.

  • Vimarsh
    Vimarsh   12 months ago

    cant be 1 lit of h20 at 4 C

  • Katniss
    Katniss   1 years ago

    1:30 Just tune a weight to the kilogram, and measure it's mass several months later to see if it has changed.

  • Alex
    Alex   1 years ago

    How much will it weigh when yellowstone buries us all in feet of ash? The same.A kilo.

  • AZZAMNO1
    AZZAMNO1   1 years ago

    why nasa haven't use metric system yet