Disseminating the New Kilogram: An International ‘Dry Run’(nist.gov)
nist.gov
Disseminating the New Kilogram: An International ‘Dry Run’
https://www.nist.gov/news-events/news/2016/11/disseminating-new-kilogram-international-dry-run
24 comments
That's very neat. It relies on the accuracy of the electrical current measurements, though; it's not an absolute measurement from fundamental physics.
For that, NIST has a fundamental standard for the standard volt.[1] So the fundamental standards now are time (atomic clock), the speed of light in vacuum, and the standard volt. The meter is now defined in terms of the speed of light in vacuum and a time.
[1] https://www.nist.gov/news-events/news/2013/04/primary-voltag...
For that, NIST has a fundamental standard for the standard volt.[1] So the fundamental standards now are time (atomic clock), the speed of light in vacuum, and the standard volt. The meter is now defined in terms of the speed of light in vacuum and a time.
[1] https://www.nist.gov/news-events/news/2013/04/primary-voltag...
Has anyone here worked in a laboratory or other environment that uses these reference masses and requires this level of precision?
Not directly, but my research group has used referenced masses and a former colleague works on the NIST watt balance.
In commodity analysis, I depend on the mere existence and cascading chain of trust descending from this exact NIST kilogram, or any other NIST mass standard that may come along.
This is a tremendous benefit even if I am not required to make my mass measurements anywhere near the level of precision which NIST is capable of itself discerning. My target for precision is simply to be measurably better than the next best operator. NIST gives a final reference against which the quality of measurement can be correctly judged.
I have personally certified many billions of dollars worth of cargo in a way which is traceable to the NIST mass standard in particular, more so than most other single-handed individuals by far. Naturally, I started early which was an unfair advantage, but I recognized the need for traceability to a primary unquestionable standard, especially when I'm advancing the underlying measurement technologies in ways which are not being published or would be difficult for less experienced operators to grasp. From an extreme viewpoint, the only alternative would be to otherwise rely on superstition.
Turns out, without knowing it, I have spent years focused on avoiding the kind of difficulties that Theranos appears to be involed in, with their emerging testing technology in their field of analysis.
I prefer my results to be traceable to NIST before they emerge from the lab.
Insurance companies have always gotten a lot more upset over a slightly incorrect result in my field compared to the field of routine blood work.
This is a tremendous benefit even if I am not required to make my mass measurements anywhere near the level of precision which NIST is capable of itself discerning. My target for precision is simply to be measurably better than the next best operator. NIST gives a final reference against which the quality of measurement can be correctly judged.
I have personally certified many billions of dollars worth of cargo in a way which is traceable to the NIST mass standard in particular, more so than most other single-handed individuals by far. Naturally, I started early which was an unfair advantage, but I recognized the need for traceability to a primary unquestionable standard, especially when I'm advancing the underlying measurement technologies in ways which are not being published or would be difficult for less experienced operators to grasp. From an extreme viewpoint, the only alternative would be to otherwise rely on superstition.
Turns out, without knowing it, I have spent years focused on avoiding the kind of difficulties that Theranos appears to be involed in, with their emerging testing technology in their field of analysis.
I prefer my results to be traceable to NIST before they emerge from the lab.
Insurance companies have always gotten a lot more upset over a slightly incorrect result in my field compared to the field of routine blood work.
It's worth watching the video just for the sound effects.
Wow the was... bad. I can get scientists want to bring SciFi to life, but this is a stretch.
In the second Artemis Fowl book, there is a centaur who uses a human laptop (magical creatures live in a technologically advanced society underground), and the first thing he does is mute it. He complains that humans are unevolved and have some sort of compulsion to make their products emit sounds and and lights.
In the second Artemis Fowl book, there is a centaur who uses a human laptop (magical creatures live in a technologically advanced society underground), and the first thing he does is mute it. He complains that humans are unevolved and have some sort of compulsion to make their products emit sounds and and lights.
Foaly was the best!
At first I thought, "Oh, these sound effects are kinda cool, to give the video a flair for the dramatic." There's not going to be any noise inside of the vacuum, but the initial sound effects were probably the noises that the contraption would make if it had air to propagate the sound waves.
But, as the video went on, the sounds effects just go more and more ridiculous. An alarm sound as the object is sent down a tube?! And the coup de grace was the lawn mower sound effect at the very end as the object was wheeled away.
But, as the video went on, the sounds effects just go more and more ridiculous. An alarm sound as the object is sent down a tube?! And the coup de grace was the lawn mower sound effect at the very end as the object was wheeled away.
Don't watch the video on mobile if you are bandwidth limited. It's 628MB for a 2 minute video.
Not quite sure how you got that number, but here are the real file sizes: 77 MiB (1080p), 49 MiB (720p), and 18 MiB (360p).
I did:
youtube-dl 'https://cdnapisec.kaltura.com/html5/html5lib/v2.47/mwEmbedFrame.php/p/684682/uiconf_id/31013851/entry_id/0_gaag5ixq?wid=_684682&iframeembed=true&entry_id=0_gaag5ixq'
Pass youtube-dl the -F parameter to see all the video formats available. In this case:
[info] Available formats for 0_gaag5ixq:
format code extension resolution note
hls-meta mp4 multiple Quality selection URL
mp4-467 mp4 640x360 467k , isom container, avc1, 29fps, ~9.29MiB
hls-478 mp4 640x360 478k
mp4-664 mp4 640x360 664k , isom container, avc1, 29fps, ~13.10MiB
hls-679 mp4 640x360 679k
mp4-904 mp4 640x360 904k , isom container, avc1, 29fps, ~18.00MiB
hls-925 mp4 640x360 925k
webm-1436 webm 1280x720 1436k , webm container, v_vp8, 29fps, ~28.50MiB
mp4-1453 mp4 1280x720 1453k , isom container, avc1, 29fps, ~28.90MiB
hls-1487 mp4 1280x720 1487k
mp4-2455 mp4 1280x720 2455k , isom container, avc1, 29fps, ~48.80MiB
mp4-3884 mp4 1920x1080 3884k , isom container, avc1, 29fps, ~77.20MiB
mpeg-32358 mpeg 1920x1080 32358k , mpeg-ps container, mpeg video, 29fps, ~627.00MiB (best)
Why does the video have goofy sound effects?
It says under the video "All sound effects added; the actual process is extremely quiet."
At 2:04 I'm pretty sure I hear the sound of a Chrysler sliding door autolock.
More about the whole process:
http://www.nature.com/news/kilogram-conflict-resolved-at-las...
Kilogram conflict resolved at last (2015)
http://www.nature.com/news/kilogram-conflict-resolved-at-las...
Kilogram conflict resolved at last (2015)
it's embarrassing that we use such a fragile process to establish a standard that is supposed to be used everywhere.
I'm not actually sure what you're insinuating here. Previously the standard WAS the "international prototype kilogram", all of which have drifted since creation (see here: https://en.wikipedia.org/wiki/Kilogram#Stability_of_the_inte... )
The problem with this is it isn't even fragile, it's _not reproducible_. The worst part is that other SI units depend on the kilogram, so they all change as this drift occurs! After a certain amount of time, how will we know what a "real" kilogram is? See here for discussion of this SI problem: https://en.wikipedia.org/wiki/Kilogram#Dependency_of_the_SI_...
The point of the watt balance approach is to make it possible for a lab to reproduce the kilogram without another kilogram reference. That's what this is about, and I don't really think it's embarrassing. I think it's very, very hard.
The problem with this is it isn't even fragile, it's _not reproducible_. The worst part is that other SI units depend on the kilogram, so they all change as this drift occurs! After a certain amount of time, how will we know what a "real" kilogram is? See here for discussion of this SI problem: https://en.wikipedia.org/wiki/Kilogram#Dependency_of_the_SI_...
The point of the watt balance approach is to make it possible for a lab to reproduce the kilogram without another kilogram reference. That's what this is about, and I don't really think it's embarrassing. I think it's very, very hard.
Why do we need these rare metals? Why not just use a block of ice generated from a known quantity of water, for example?
I'm not sure why ice would matter given that it should weigh the same as in the liquid form, but...
How do you measure a known quantity of water to within a few tens of parts per billion? Do you specify the proportion of light to heavy water? (For 'normal' water about 1 in 41 million.) What about contaminants in the water? There are so many uncertainties that it's impossible for all practical purposes.
The whole point of using 'rare' silicon is that we already have commercial processes for producing ultrapure, defectless, monocrystals of the stuff (for use in computer chips), so it's easy to reuse that technology for defining a kilogram.
How do you measure a known quantity of water to within a few tens of parts per billion? Do you specify the proportion of light to heavy water? (For 'normal' water about 1 in 41 million.) What about contaminants in the water? There are so many uncertainties that it's impossible for all practical purposes.
The whole point of using 'rare' silicon is that we already have commercial processes for producing ultrapure, defectless, monocrystals of the stuff (for use in computer chips), so it's easy to reuse that technology for defining a kilogram.
The prototype kilogram was made of platinum-iridium because they are very nonreactive and fairly hard, so once the prototype was made it would be unlikely to be accidentally modified.
If you tried to use water ice as a standard, you'd find that its mass was changing all the time as the ice sublimated away, or humidity condensed onto its surface. It would be impossible to make precise measurements.
If you tried to use water ice as a standard, you'd find that its mass was changing all the time as the ice sublimated away, or humidity condensed onto its surface. It would be impossible to make precise measurements.
Because you don't want that lump of mass to change in any way while it is being used as a reference.
Are you aware of all the matter exchange processes that are continuously going on at the surface of water ice under normal conditions?
Are you aware of all the matter exchange processes that are continuously going on at the surface of water ice under normal conditions?
Necroposting, I know, but under what definition is silicon a "rare metal"?
http://scitation.aip.org/content/aapt/journal/ajp/83/11/10.1...
(Open Access)