We can't seem to count on anything anymore...

[JohnRBaker]

It appears that the standard, or "prototype", Kilogram as been mysteriously losing mass and no one knows exactly why, hence the mystery. Now this is critical since the Kilogram is the only remaining international unit-of-measure which is still based on a physical artifact, in this case, a lump of metal locked in a safe in France. So the powers-that-be are about to redefine the Kilogram once and for all, basing it on something that can be reproduced at any time, anywhere, without having to go to France to make sure that you've got it right.

For more about this issue and the proposed solution that is being considered, go to:

https://gizmodo.com/scientists-are-redefining-the-kilogram-1782362460

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
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The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[dik]

Reminds me of the Kronecker (delta) comment, "God created the natural numbers, all else is man made." Even the existence of a 'zero' came along several centuries later.

Dik

 

[waross]

https://gizmodo.com/scientists-are-redefining-the-kilogram-1782362460[/URL]]Also, over time, the various artifacts have been diverging from each other in terms of mass. Even when stored carefully under bell jars, the replicas have been slowly gaining mass by absorbing contaminants in the atmosphere, although periodic cleanings can help minimize that gain. The IPK itself is actually losing mass, relative to all its official copies, a phenomenon which frankly baffles physicists.

I find the divergence troubling. If all the standards are diverging, how can we be sure that the Paris standard is losing weight and not just gaining less than the others?
Possibly we can refer back to the gramme which was defined as the weight of one cubic centimetre of water at +4 Celsius.
Is the specific weight of water now in question?
Many scientists are happiest when a real world phenomenon agrees with their calculations.
Many engineers are happiest when their calculations agree with a real world phenomenon.
An engineer once commented on the advantages of using air as an insulator;
"Cheap, light and easy to cut and drill."
Pure water may be more expensive than tap water but it may still be cheaper than pure platinum.
What happens to the system is the weight of one cubic centimetre of water is no longer exactly one gramme?
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

No, it's just horrifically messy to deal with water, particularly without its container, which can get contaminated or lose weight as well, not to mention the evaporation of the water ;-)

Not to mention, also, 1 cc of water is rather tiny mass to play with, which is why the kilogram as a unit is much more useful, which is why it's the only fundamental unit that's got a prefix

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[waross]

Sorry IRstuff.
I was editing as you were posting.
Your post is still fair comment.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[IRstuff]

In any case, this is all the more reason to find a non-physical artifact, although, the complexity goes up substantially over a simple cylinder of Pt/10Ir

The divergences of ALL other daughter/sister standards are positive relative to the IPK, including several standards that presumably have gotten kid-glove care that show the largest divergence. So, without a watt-balance or similar, we actually don't know what's happening, but given the choice of the French being wrong or the entire rest of the world, which one is incorrect, hmmm...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[Artisi]

Following on from IRstuff commenting on 1cc of water is a tiny mass and difficulty to play with, this could also be likened to beer, hence the reason why beer should only be served in 1 litre containers.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[berkshire]

Definitely not ,
True beer should only be served in one pint containers 20 fluid ozs .
Of course I would have some who would argue that true beer is actually ale , but then that is better than a weak mixture made by Lageren.
B.E.


You are judged not by what you know, but by what you can do.

 

[waross]

The point I wanted to make is that if all the standards are changing, how do they know whether the Paris standard has lost mass or just not gained as much mass as the other standards?
Did they go back to the cubic centimetre of water for an accurate standard?
How else to tell if all the other standards no longer agree?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[hokie66]

If the volume of water is too small, then use a litre, which is a kilogram. Or a cubic metre, which is a tonne. But I suppose the larger you go, the messier it is.

 

[dik]

Then you have to worry about the container changing weight... just can't win for losin'

Dik

 

[SomptingGuy]

the kilogram as a unit is much more useful, which is why it's the only fundamental unit that's got a prefix

Which catches me out all the time, in a round-about way. When I'm writing code that reads mg, I ALWAYS forget that to convert mg to SI, you need to divide it by 1e6, not 1e3, as its prefix always suggests to me. Grrrr!

Steve