The new reference kilogram is an engineering marvel, but I’ve always wondered this: why didn’t they just build a reference gram instead? Seems like that would be at least a thousand times easier to pull off.
An old artifact kept in a vault outside Paris is no longer the standard kilogram
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Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#82Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#83The new reference kilogram is an engineering marvel, but I’ve always wondered this: why didn’t they just build a reference gram instead? Seems like that would be at least a thousand times easier to pull off.
Likely a lot harder to get the tolerances down on something much smaller.
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#84Earlier quoted context omitted.
How about we keep the current name and use it as a basis for prefixing? gram -> millikilogram milligram -> microkilogram metric ton -> kilokilogram ...never mind.
It's almost a crime that a metric ton isn't called a "megagram". Aside, are the mega and giga prefixes ever used for anything except bits and bytes? (Edit: OK, OK. I forgot about megaohms, megahertz, megawatts. Also megapixels and Megadeth.)
Gigawatts were popularized in a certain movie :)
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#85I've always been mildly irritated that the name of the SI mass base unit has a prefix. Second, liter, meter, Newton, kilogram. Were I emperor of the world I would slide the name scale up so the mass equal to 2.205lbs was called a gram.
If you were emperor of the world, I would implore you to finance a multibillion dollar project to measure the gravitational constant to higher percision so that we could move to units that actually make sense. https://en.wikipedia.org/wiki/Planck_units
Came here to mention the Planck units, aka God's units :)
Sadly they are a little outside of the human realm of experience, both in their single units (waaay to small usually) and in the units that the list contains (speed, electrical charge, etc; where we like "introductory" units such as length, time, weight)
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#86Earlier quoted context omitted.
It's almost a crime that a metric ton isn't called a "megagram". Aside, are the mega and giga prefixes ever used for anything except bits and bytes? (Edit: OK, OK. I forgot about megaohms, megahertz, megawatts. Also megapixels and Megadeth.)
> and Megadeth.) Laughed at that one.
Megadeth is named after the term “megadeath”, a unit in Cold War calculations of possible nuclear attacks to designate a million deaths. The 80’s were a grim time. (You can actually see in the film Dr. Strangelove a scene where George C. Scott’s character leans over a binder labeled “World Targets in Megadeaths”.)
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#87>Despite the greatest of precautions, every time the standard kilo was handled — for example, to compare it to another unit that could then be used to calibrate instruments — it would shed some atoms and its mass would be slightly changed. Over its lifetime, that standard kilo is estimated to have lost about 50 micrograms. Why did the standard kilo ever need to be handled? Just store it on a balance and only handle t…
I think they needed to take the replicas from other countries like the US to the master one in Paris for comparison every year.
Edit: see this Veritasium episode https://youtu.be/SmSJXC6_qQ8
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#88>Despite the greatest of precautions, every time the standard kilo was handled — for example, to compare it to another unit that could then be used to calibrate instruments — it would shed some atoms and its mass would be slightly changed. Over its lifetime, that standard kilo is estimated to have lost about 50 micrograms. Why did the standard kilo ever need to be handled? Just store it on a balance and only handle t…
The balance still would need to be balanced.
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#89The new reference kilogram is an engineering marvel, but I’ve always wondered this: why didn’t they just build a reference gram instead? Seems like that would be at least a thousand times easier to pull off.
As covered in the article, the reference object loses some of it's atoms every time it is handled. The smaller the reference object, the larger the relative error induced this way.
Re: An old artifact kept in a vault outside Paris is no longer the standard kilogram
#90>Despite the greatest of precautions, every time the standard kilo was handled — for example, to compare it to another unit that could then be used to calibrate instruments — it would shed some atoms and its mass would be slightly changed. Over its lifetime, that standard kilo is estimated to have lost about 50 micrograms. Why did the standard kilo ever need to be handled? Just store it on a balance and only handle t…
At this precision you weigh things twice. Once with the reference on the left arm of the balance and the test object on the right and another time with objects swapped.