# What would happen if someone broke the "Grand Kilogram" **URL:** \ **Category:** Factual Questions\ **Created:** [July 2, 2016, 3:31pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923 "2016-07-02T15:31:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [July 2, 2016, 3:31pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/1 "2016-07-02T15:31:21Z")
The thread about [kilograms](http://boards.straightdope.com/sdmb/showthread.php?t=797280) made me remember this from physics class. As we all know, the Kilogram is legally defined as the mass of a specific metal ingot. What would happen if someone broke it? I had a physics professor who often said a bad guy could do major economic damage by breaking the “Grand Kilogram”, because it would mean that we would lose all our measurement standards. He was probably exaggerating, but what would happen? ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [July 2, 2016, 3:41pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/2 "2016-07-02T15:41:29Z")
We’d make a new one using the copies? Sent from my SM-G900T using Tapatalk ---
**Author:** ![Absolute](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@Absolute](https://boards.straightdope.com/u/Absolute)\ **Post date:** [July 2, 2016, 3:43pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/3 "2016-07-02T15:43:28Z")
There are several other reference kilograms throughout the world, and these have been periodically measured against the master copy. Presumably, we’d just starting using one of them as the master copy. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [July 3, 2016, 7:37pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/4 "2016-07-03T19:37:16Z")
The vast majority of us would never know (unless we saw it in the news) and would never be affected at all. How often do you ever weigh a box of cereal or piece of meat from the store to see if it weighs what it says on the label? In fact, how often do you need to know the precise weight of anything? ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [July 3, 2016, 8:16pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/5 "2016-07-03T20:16:41Z")
> [@t-bonham@scc.net](#): > > The vast majority of us would never know (unless we saw it in the news) and would never be affected at all. > > How often do you ever weigh a box of cereal or piece of meat from the store to see if it weighs what it says on the label? In fact, how often do you need to know the precise weight of anything? I have a home-based business and ship my own products. I have a postal scale that can weigh in either ounces or grams, up to 5 pounds. An exact weight is not necessary; if it’s under 13 ounces, I round it up to the next ounce to account for labels, etc. and if it’s over, a program calculates it for me. Like others have said, I’m sure there are duplicate master copies in multiple locations in the event of a natural or man-made disaster. ---
**Author:** ![Emtar\_KronJonDerSohn](https://avatars.discourse-cdn.com/v4/letter/e/58956e/32.png) [@Emtar\_KronJonDerSohn](https://boards.straightdope.com/u/Emtar_KronJonDerSohn)\ **Post date:** [July 3, 2016, 8:26pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/6 "2016-07-03T20:26:14Z")
I understand the official kilogram has actually mysteriously been losing weight since originally constructed and is in some way already “broken.” Look how messed up we already are, amiright? ---
**Author:** ![DataX](https://avatars.discourse-cdn.com/v4/letter/d/e99b99/32.png) [@DataX](https://boards.straightdope.com/u/DataX)\ **Post date:** [July 3, 2016, 8:32pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/7 "2016-07-03T20:32:43Z")
Not only are there “Duplicates”, but these are handled extremely carefully and monitored over time to detect differences. The IpK/Le Grand K was/is last time I checked locked in a safe in France (or maybe it was Begium) with three sperate keys needed to open it. I think this is done mainly for pomp and circumstance, but they do take it seriously. Nevertheless - the IPK itself is rarely handled - individual countries got their own copy - several dozen were made originally and the US uses one of these as the official US Kilogram. They track stuff like temperature, density, Gravity, air pressure, humidity, … Here’s a graph of the kinda drift that can be seen among some of the sister copies of the IPK [![](https://en.m.wikipedia.org/wiki/Kilogram#/media/File%3APrototype_mass_drifts.jpg) ](https://en.m.wikipedia.org/wiki/Kilogram#/media/File%3APrototype_mass_drifts.jpg) You can see how they diverge and how one could make an educated guess on the value of the IPK based on a relatively simple model. I believe, but am not sure, that they are supposed to be replacing the IPK with a non physical standard (the last of the SI standards to be decoupled from an object). While I a, a huge believer in standards - I don’t think the loss of this standard would have any real effect on 99.9999% of us. Every once in a while you’ll see NIST update or change some constant or number used in physics or math. My guess is the greater precision of the IPK and US standards allows this to happen and maybe we wouldn’t know constant X to an extra 2 digits if they were less careful. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [July 3, 2016, 8:44pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/8 "2016-07-03T20:44:46Z")
What would the (criminal) charge be? ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 3, 2016, 8:55pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/9 "2016-07-03T20:55:21Z")
> [@Leo\_Bloom](#): > > What would the (criminal) charge be? Gram theft. ---
**Author:** ![I\_Love\_Me\_Vol.I](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/i_love_me_vol.i/32/521_2.png) [@I\_Love\_Me\_Vol.I](https://boards.straightdope.com/u/I_Love_Me_Vol.I)\ **Post date:** [July 3, 2016, 8:58pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/10 "2016-07-03T20:58:48Z")
> [@Leo\_Bloom](#): > > What would the (criminal) charge be? Ooooh, you are a _top_ set-up man. Top! With a well-weighted delivery\*, it was nice of you to leave the glory for **John Mace**. Well done. \*Been watching a lot of soccer. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 3, 2016, 9:07pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/11 "2016-07-03T21:07:14Z")
> [@Leo\_Bloom](#): > > What would the (criminal) charge be? Mass murder. ---
**Author:** ![velomont](https://avatars.discourse-cdn.com/v4/letter/v/8491ac/32.png) [@velomont](https://boards.straightdope.com/u/velomont)\ **Post date:** [July 3, 2016, 9:26pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/12 "2016-07-03T21:26:41Z")
> [@Mangetout](#): > > Mass murder. I guess the perpetrator would be a serial kilo. ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [July 3, 2016, 11:36pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/13 "2016-07-03T23:36:52Z")
Would the penalty exact roughly 2.2 pounds of flesh? ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [July 3, 2016, 11:47pm UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/14 "2016-07-03T23:47:30Z")
Or more exactly exact 2.204622622 pounds of flesh ---
**Author:** ![nate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nate/32/13085_2.png) [@nate](https://boards.straightdope.com/u/nate)\ **Post date:** [July 4, 2016, 12:38am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/15 "2016-07-04T00:38:45Z")
> [@Emtar\_KronJonDerSohn](#): > > I understand the official kilogram has actually mysteriously been losing weight since originally constructed and is in some way already “broken.” Look how messed up we already are, amiright? I wonder how they know it’s losing weight… do they just compare it to other labs’ copies and see that the copies weigh more and therefore conclude the standard weighs less? After all, if there were a way to measure the kg more accurately than the kg itself, then it wouldn’t really be THE standard would it? ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [July 4, 2016, 12:59am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/16 "2016-07-04T00:59:14Z")
> [@Mangetout](#): > > Mass murder. Monsieur, bravo. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 4, 2016, 1:13am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/17 "2016-07-04T01:13:17Z")
I was never much a fan of it but I remember a scene from _The John Larroquette Show_ back in the 90s. He ran a bar in an airport or something and one day this guy from The US Dept of Weights & Measures comes in and needs to use the restroom, and he’s traveling with ‘the inch’, a small piece of metal representing the standard length. So he leaves it with Larroquette while using the bathroom, and of course he can’t resist opening the case and looking at it. He takes out a ruler from his desk and compares it and nods approvingly. Then someone surprises him and he slams the case shut, and dents it\*!\* Eventually the govt guy comes back and freaks out. Larroquette tells him to just re-mark it using his ruler and the guy shouts,\* “Oh sure! Do I go to the left of the line or the right of the line? **Or do I guess the center?!?!** ”\* ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 4, 2016, 1:29am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/18 "2016-07-04T01:29:46Z")
No worries here in the United States … the [slug](https://en.wikipedia.org/wiki/Slug_(mass)) is a derived unit based on the pound … strictly an absolute value depended on longitude, latitude and elevation. ---
**Author:** ![nate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nate/32/13085_2.png) [@nate](https://boards.straightdope.com/u/nate)\ **Post date:** [July 4, 2016, 2:32am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/19 "2016-07-04T02:32:41Z")
There is a big meeting coming up either this year or next, I can’t remember off-hand, where the the SI system will be redefined, I think the goal is to attempt to relate every unit back to fundamental constants and/or the second as time can be measured accurately to like 13 decimal places or something. The final parameter that is still based on an artifact is the kg so these national metrology labs are all competing to come up with a new way to determine the kg based on the second (and physical constants) before this big meeting in Paris. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [July 4, 2016, 3:31am UTC](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923/20 "2016-07-04T03:31:36Z")
> [@nate](#): > > There is a big meeting coming up either this year or next, I can’t remember off-hand, where the the SI system will be redefined, I think the goal is to attempt to relate every unit back to fundamental constants and/or the second as time can be measured accurately to like 13 decimal places or something. The final parameter that is still based on an artifact is the kg so these national metrology labs are all competing to come up with a new way to determine the kg based on the second (and physical constants) before this big meeting in Paris. That was what I was going to ask- why not have it defined in terms of some fundamental constant, instead of as a specific object? [Next page](https://boards.straightdope.com/t/what-would-happen-if-someone-broke-the-grand-kilogram/758923.md?page=2)