back to article Boffins weigh in to perfect kilogram quest with LEGO kit

How many boffins does it take to make a LEGO machine to measure a fundamental physical unit? Nine, apparently – but the outcome, a LEGO watt balance, can measure a kilogram with about one per cent inaccuracy. The serious point to the National Institute of Standards and Technology-led effort (NIST) is that with the Le Système …

  1. MrDamage Silver badge

    One percent accuracy

    I can just look at something and guestimate its weight with a 1% chance of accuracy.

    I do believe you mean margin of error. Or 99% accuracy.

    But enquiring minds want to know, how accurate is it at measuring jubs?

    1. Anonymous Coward
      Anonymous Coward

      Re: One percent accuracy

      More to the point, $600 for something that is only 99% accurate doesn't seem like very good value for money.

      1. Oninoshiko
        Thumb Up

        Re: One percent accuracy

        It's not about value, it's about cool.

        A Lego watt balance is vary cool.

    2. Charlie_Manson

      Re: One percent accuracy

      In the linked article it says that is measures a gram with 99% accuracy. So scaling it up would mean measurings a kilogram to 99.9% accuracy

  2. Anonymous Coward
    Anonymous Coward

    One word

    Cool!

    1. Christoph

      Re: One word

      SCIENCE!

  3. Anonymous Coward
    Anonymous Coward

    $600!?

    About the same cost as a couple of standard Lego sets then? :o)

  4. Mage Silver badge

    Interesting

    So would Mecanno be more accurate?

    What limits the accuracy?

    1. Martin
      Headmaster

      Re: Interesting

      Not Mecanno. Nor yet Mechanno, as suggested a little further down.

      Meccano.

  5. Snorlax Silver badge
    Thumb Up

    At least they didn't refer to the bricks as "Legos" like most of their fellow Americans insist on doing.

    1. Anonymous Coward
      Anonymous Coward

      @snorlax

      Is it really necessary to insert an anti american statement into EVERY post you make or are you normally such a dick?

      Lego's & Jello are both names that became the common reference for the entire class of product.

      This is something any manufacturer would gladly wish for. Mechanno and Playmobil are far less common in the States than Lego.

      1. Snorlax Silver badge
        FAIL

        Re: @snorlax

        Is it really necessary to insert an anti american statement into EVERY post you make or are you normally such a dick?

        Yeah I'm a dick. You got me, Anonymous Coward.

        1. Martin Budden Silver badge
          Childcatcher

          Re: @snorlax

          Fight! Fight! Fight!

  6. David Pollard
    Pint

    Brian Cox ...

    ... eat your heart out. You have competition.

    1. Sweep

      Re: Brian Cox ...

      Yes Brian, please do...

  7. Anon

    Not BLI

    It's BIL. Goes along with BeV. BIL and BeV, easy to remember. Now, if I could only remember what they went with...

    1. Roger Varley

      Re: Not BLI

      Flowerpots?

      1. hopkinse

        Re: Not BLI

        flubbalub!

    2. This post has been deleted by its author

  8. G R Goslin

    But

    But, surely, all the factors used in assessing the mass are all similarly undefined, or defined by statutory standards.

    1. Bluewhelk
      Boffin

      Re: But

      Not so, the kilogram is now the only standard defined by a physical object.

      For example the metre is the length travelled by light in vacuum during a time interval of 1/299792458 of a second and a second is 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

      So while in a well equipped laboratory boffins can make their own metre and second they have to trog off to Paris to compare their kilo with the actual standard (a lump of platinum iridium alloy). In practice each country has a copy or two of the original or access to someone else's.

      Worse still the standard kilo (as located in Paris) appears to be CHANGING (not a lot, but enough).

      1. Snorlax Silver badge

        Re: But

        "Worse still the standard kilo (as located in Paris) appears to be CHANGING (not a lot, but enough)."

        What's "enough"? A couple of µg or mg over my lifetime?

        1. Bluewhelk

          Re: But

          50ug in 100years according to ...

          http://www.bipm.org/en/bipm/electricity/watt_balance/

          Metrologists don't like things that change.

          1. Snorlax Silver badge
            Pint

            Re: But

            50ug in 100years according to ...

            Interesting, cheers

        2. BristolBachelor Gold badge

          Re: But

          "Worse still the standard kilo (as located in Paris) appears to be CHANGING (not a lot, but enough)."

          I read that they found out that it was accumulating mercury from the air. They had a standard one that was kept sealed, and the day-to-day standard. Every now and then, they would compare them, and found that the day-to-day weight was gaining mass. The last guy who was qualified to polish and clean it, did a final clean before he retired and they analysed what came off. They assumed that the mercury came from the breath of the staff who had amalgum fillings.

      2. Anonymous Coward
        Anonymous Coward

        Re: But

        virtual particles in vacuum! speed of light abolished!

      3. Martin
        Happy

        Re: But

        For example the metre is the length travelled by light in vacuum during a time interval of 1/299792458 of a second and a second is 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

        If you were quoting those from memory, I'm impressed.

  9. Francis Boyle Silver badge

    I demand neodymium ring magnets based Lego

    Lego + magnets = pure win.

    1. WhatAboutBob

      Re: I demand neodymium ring magnets based Lego

      Lego used to do do magnets, just not neodymium ones. They were used in the M-Tron space sets and to connect the carrages on train sets. And yes they were pure win.

      1. Anonymous Coward
        Anonymous Coward

        Re: I demand neodymium ring magnets based Lego

        I seem to remember thingies that could lift / pick up other thingies using a magnet and a thin piece of rope

        1. Frederic Bloggs

          Re: I demand neodymium ring magnets based Lego

          Ah, so you had that kiddies game that allowed players to dip their magnets attached to small rods (with string) into a pot and obtain cardboard fish with metallic noses as well then?

  10. FartingHippo
    Paris Hilton

    I don't get it

    The calculation requires knowledge of 'g' which varies depending on your position in space (or your location on Earth). How do you get 'g' without knowing a great deal more than the planck constant?

    1. Mage Silver badge

      Re: I don't get it

      That might explain the low accuracy.

    2. Bluewhelk

      Re: I don't get it

      You measure how fast an object accelerates when dropped in a vacuum (or thrown up and let drop), this can be done accurately using interferometry. This is then only reliant on the standards for distance and time.

      See absolute "Gravimeter".

  11. J.G.Harston Silver badge

    Great for schools

    I remember doing school physics experiments to measure /g/ and /c/. We also worked out the Plank wavelength of a cat....

    1. Chemist

      Re: Great for schools

      " Plank wavelength of a cat...."

      I was always taken with the requirement that to demonstrate any interference in a slit experiment you'd have to have an incoherent cat-beam. Suppose that's easy enough.

      Also I guess that a sleeping cat has a zero-point energy that is actually zero

      I think it's de Broglie wavelength BTW

  12. JacobZ
    Joke

    A simpler solution...

    ...is to redefine the fundamental unit of mass in terms of the standard Lego 4x2 brick. They are universally available, not to mention easy to find in the dark in bare feet.

    1. Anonymous Coward
      Anonymous Coward

      Re: A simpler solution...

      Unfortunately their weight varies somewhat based on how many times you've used your teeth to pry 2 of them apart... Or is that just my set?

  13. Stevie

    Bah!

    Real scientists don't use one letter to do different duties in one equation.

    Because capslock typos happen to everyone.

    1. Martin Budden Silver badge

      Re: Bah!

      Everyone except me. Years ago I prised the Caps Lock key off my keyboard and put it in my desk drawer, where it still resides.

      I've often thought that Caps Lock is the most useless key on a standard keyboard, and I would love to design a new keyboard layout which is identical in every way except that it replaces the Caps Lock key with the oft-need-yet-non-existant Any key.

      1. Stevie

        Re: I prised the Caps Lock key off my keyboard

        But ... how do you shout?

        1. Martin Budden Silver badge
          Happy

          Re: @ Stevie

          Of course I would never dream of shouting (*polishes halo*), but on the very rare occasions I want to type in all uppercase I hold down the shift key.

      2. wdmot

        Re: Bah!

        Used to be some keyboards had Ctrl in that location -- Amiga, Omni, Data General... but you're right, I haven't found any yet that have the Any key.

  14. Glenturret Single Malt

    Weight?

    Are we talking about mass here, not weight?

  15. jdgalt

    Is there still an exact answer at all?

    Since the Standard Kilogram has been declared no longer trustworthy, and ISO (or whoever decides) has yet to choose a substitute, I submit that there's no such thing right now as a true exact kilogram anyway.

    They never commented on my proposal, which is to simply make 1 kg = the mass of 1000 cc of water, thus defining the kilogram in terms of the meter.

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