Main » Discussion » PSA: The kilogram has been redefined » New reply
    Alert
    You are about to bump an old thread. This is usually a very bad idea. Please think about what you are about to do before you press the Post button.
    New reply
    Post help

    Presentation

    [b]…[/b] — bold type
    [i]…[/i] — italic
    [u]…[/u] — underlined
    [s]…[/s] — strikethrough
    [code]…[/code] — code block
    [spoiler]…[/spoiler] — spoiler block
    [spoiler=…]…[/spoiler]
    [source]…[/source] — colorcoded block, assuming C#
    [source=…]…[/source] — colorcoded block, specific language[which?]
    [abbr=…]…[/abbr] — abbreviation
    [color=…]…[/color] — set text color
    [jest]…[/jest] — you're kidding
    [sarcasm]…[/sarcasm] — you're not kidding

    Links

    [img]http://…[/img] — insert image
    [url]http://…[/url]
    [url=http://…]…[/url]
    >>… — link to post by ID
    [user=##] — link to user's profile by ID

    Quotations

    [quote]…[/quote] — untitled quote
    [quote=…]…[/quote] — "Posted by …"
    [quote="…" id="…"]…[/quote] — ""Post by …" with link by post ID

    Embeds

    [youtube]…[/youtube] — video ID only please
    Thread review
    KoiMaxx Here's a pretty neat representation of the seven base SI units (inner ring) and how they relate to the physical constants (outer ring) and each other.
    ‮strfry("emanresu") Are the ratios so awkward and clumsy, though? If you want to get riled up about units, the 1954 redefinition of the degree Celsius is far more disgusting.

    I always think of it like having several definitions, one for each level of precision.

    So the meter's 'common sense' definition is the length of a seconds pendulum. Then for basic scientific measurements, you'd use the meridian definition, and for serious ones the one with the speed of light.

    And from that, you get the liter, and from that the kilogram.

    This allows me to pretend that the metric system is perfectly logical, while disregarding all evidence to the contrary, or treating as a "neat approximation trick". Everybody's happy.
    CaptainJistuce
    Posted by funkyass
    Posted by KoiMaxx
    @Nicolas Steel
    In the simplest terms: the value of the kilogram is no longer dependent on a single physical object (i.e. the IPK), but rather on a defined mathematical concept.


    more correctly, all the base units of the SI system are now defined either as ratios to universal constants, or measurements of physical phenomena.
    Awkward and clumsy ratios chosen to avoid actually changing anything, which flies in the face of the original intent of the system(which was, admittedly, "let's break everything just to be different!". The french revolution was a fun time.).
    funkyass
    Posted by KoiMaxx
    @Nicolas Steel
    In the simplest terms: the value of the kilogram is no longer dependent on a single physical object (i.e. the IPK), but rather on a defined mathematical concept.


    more correctly, all the base units of the SI system are now defined either as ratios to universal constants, or measurements of physical phenomena.
    tomman > You are about to bump an old thread. This is usually a very bad idea. Please think about what you are about to do before you press the Post button.

    This time is actually a GOOD idea: as a reminder, the new reference for the kilogram is now active, starting TODAY.

    Have you already recalibrated your calibrators?
    CaptainJistuce
    KoiMaxx
    Posted by DonJon

    Off topic, TIL I'm a ""Sun Sneezer". Or rather I should say: Today I learned that most people are not. I simply thought everyone had that same reaction.

    Hey, welcome to the club! :D

    Back to topic -- I love physics/maths topics, even though honestly a lot of the complex concepts still go over my head. I was actually quite excited when I heard the redefinition of the kilogram was officially ratified. I'm kind of weird that way :P
    DonJon
    Posted by Nicholas Steel
    That video gives me a new appreciation of my hatred of maths. None of what he said explained anything in an easily understood way.


    My maths are pretty bad and I don't think that was the hard part..The physics otoh...

    Posted by KoiMaxx
    @Nicolas Steel
    In the simplest terms: the value of the kilogram is no longer dependent on a single physical object (i.e. the IPK), but rather on a defined mathematical concept.

    Basically.


    Off topic, TIL I'm a ""Sun Sneezer". Or rather I should say: Today I learned that most people are not. I simply thought everyone had that same reaction.

    Although for me it's not quite as strong as what he described in the video: I don't get the sneeze reflex just from going from dark to light. I must have an already itchy nose, otherwise, nothing happens. Also I don't have to look directly at a bright light,just be exposed to light is enough (looking directly at the sun like he seem to be doing in the video is probably a bad idea).


    So maybe amongst people who have the gene some have it expressed more than others? I don't know.
    KoiMaxx @Nicolas Steel
    In the simplest terms: the value of the kilogram is no longer dependent on a single physical object (i.e. the IPK), but rather on a defined mathematical concept.
    creaothceann Because it's the in-depth version, not exactly the "in layman's terms" imo.
    Nicholas Steel That video gives me a new appreciation of my hatred of maths. None of what he said explained anything in an easily understood way.
    DonJon I actually was made aware of this from this vid more than a year ago I think.Does a decent job explaining in layman's terms what's actually going on:
    https://www.youtube.com/watch?v=Oo0jm1PPRuo

    Concretely,you're not going to weigh more or less in kilos,not in any significant ways at least
    KoiMaxx So I guess The kilogram is now a kilogram? Neat!
    Covarr xkcd is on the case.
    Kakashi Drugs aren't measured in metric units for the most part.
    Kawaoneechan I am pleased with this news.
    tomman https://www.bbc.com/news/science-environment-46143399
    https://science.slashdot.org/story/18/11/16/162253/kilogram-gets-a-new-definition

    A bunch of scientists have decided that the current reference for the kilogram (a shiny cylinder made of pure platinum safely stored somewhere in France) is no longer accurate (apparently metals age or something, losing weight and therefore rendering any speck of accuracy completely moot), and they have been pushing for years to switch to non-material ways to define weight. They've succeeded, and starting in 2019/05/20, the kilogram will now be based to the Planck constant, or the mass of a particle of energy (correct me if I'm wrong, but we were never taught such advanced stuff at school, and I didn't pursued a career in pure physics).

    Mind you, this also hits other SI base units, to match the same criteria already used for measurements like length and time. And if you're one of those Imperial system smartasses, think again: your glorious pound is already tied to the reference kilogram, which means these changes WILL impact those LOLunits too.

    Anyway, if you're a drug dealer concerned about the accuracy of your weight scales, better procure one of those fancy scales as these will be the new gold standard.
      Main » Discussion » PSA: The kilogram has been redefined » New reply
      Yes, it's an ad.