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The Changing Definition Of 'Kilogram'
DrLudicrous writes "The NYTimes is reporting that the platinum-iridium standard mass for the kilogram is shedding at an appreciable rate -- at least compared to other reference masses. The Pt-Ir cylinder is kept in France, and measured annually, and the slight discrepancy is important because the kg is an SI base unit- thus other quantities such as the Volt are based on it. A new standard is being sought- the two frontrunners are counting the number of atoms in a perfectly spherical single crystal of silicon, and another technique uses a device known as the Watt balance."
Hey I live in America you insensitive clod! (but then again I alawys want to know how much they are lifting on Strongman Competition).
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Everytime she steps on the scales...I would tell you what it was defined as last week, but kids may be reading this.
The problem with the single crystal of silicon method, a few years ago, was that there were all these lattice vacany defects cropping up. The formation of such point vacancies is so entropically favoured that I don't think they can ever eliminate them...
Since there is only one reference object for the kilogram, everything else is just a copy -- and even if it is a first generation copy, errors are bound to creep in.
The redefinition of the kg is long overdue, mad props to the scientists working on this.
Darn right! After all, it's easy enough to convert fortnights to stone with a Mayan calendar.
We're going to in the future eventually. It's inevitable.
I know it's 60 firesticks per 100 Watts, and 3000 Volts per staticy tomcat, but it might just be easier if we all just jumped in and switched to metric 144%.
I mean picture doing 100 on the highway! Wouldn't that be great? And dozens of future Mars landers would actually land on Mars, instead of digging ideal tree planting holes and landscaping future martian neighbourhoods. ("Zyphod! Incoming! It's the Americans!")
No more two sets of wrenches and lost sockets! Now you can have one set of sockets with half the sockets missing, instead of two sets of sockets with half the sockets missing. And no more asking for an 5mm and trying to make a 1 3/4" fit, rounding off the edges and carving a perfect turkey slice off your hand and gushing gallons of blood. It would be litres, which is less.
And you get to tell women that you, sir, are endowed with twenty-two centimeters of man!
Of course, the loss of the 25 cent piece will be a negative, since we'll have to pay for everything in dimes. But it's worth it dammit.
Seriously, we all know this is going to happen. When are we on board? Are we that stubborn?
The baby's fine -- please stop sending business cards.
It's not the arbitrariness, but the fact that metric is a decimal system.
The only countries left that don't use metric are the US and Bhutan. Bhutan is a fundamentalist islamic country that doesn't even have any phones yet. I guess we can see what the US' technical level is.
The only known quantity of Unobtainium (UB238) has gone missing.
The 1 kilo square block was being held in Brussels awaiting return to Brazil, where it was originally unearthed.
It was determined that the physical stability of the material was being affected by being moved from it's original location, that of being south of the equator. Investigators are anxious to reclaim the material in hopes of stabalizing it's rumored flux in mass. The UB238 was being packaged for transit, when it suddenly dissapeared from the shipping room counter. The rumor that it had created, and subsequently fallen into, a 'portable black hole' was discounted by investigators on the scene.
Once the Unobtainium is recovered, and returned to Brazil, it can be weighed and certified as a replacement for the Pt-Ir cylinder that is kept in France, and measured annually, representing the kilo standard for the world.
MPEG at 11.
The posted article, while interesting, is wrong about the volt being based on the Kilogram. Since about 1990, the volt is defined to be the voltage applied to a Josephson junction that produces a frequency of 483,597.9 GHz. This new standard was implemented in order to get away from relying on 'artifact' standards (such as the Kg cylinder). One quick source page on Josephson junctions (which completely revolutionized the field of Metrology back when I was a calibration tech in the AF) is:/ squid.html
http://hyperphysics.phy-astr.gsu.edu/hbase/solids
If I recall correctly, the eventual goal of the international standards organization was to find ways to define everything in terms of frequency/time since we can measure time so accurately/precisely.
So I now weigh 75kg...give or take a bit :o
Wait till I tell my fiance that her weight
fluctuates on a weekly basis!
A better way would be to invent an all new imperial-style system for measuring computer storage. That way, there would be no chance for confusion with any base-10 system. For example:
korb = 3 bytes
fleb = 12 korbs
splin = 20 fleeb
fnit = 6 splins
Fnit = 6000 splins
frush = 48 fnits
watz = 18 frushes (19.5 frushes in the U.K.)
spoff = 480 watzen
nurm = 320 spoffs
long nurm = 80 nurm
munnel = 24 long nurm
This system easily covers storage capacities up to today's confusingly named "petabyte". Plus, there's no ambiguity about what you're measuring. Any of these units implies bytes of storage, which is a much cleaner solution.
The computer I'm using now has 71+29/32 watzes of system memory and 44+10/16 spoffs of disk space. There's no confusion about fuzzy definitions of "mega" with that measurement.
Fundamentalist Islamic country without any telephones?
Can I have some of whatever your smoking please?
More than mere navel gazing.
The kilo shall be defined to be 1/80 of my weight. In return for the honor I promis to make the worlds people slim down.
Trolling is a art!
Just to confuse the matter more, in the 1970s, it was common to use metric sizes of threaded copper pipe, which had external diameters in sizes approximating common fractions of inches: 13mm = 1/2", 16mm = 5/8" and 19mm = 3/4" just to mention some of them. These appearently were all threaded with 1mm pitch threads.
Later, these were replaced by true metric pipe sizes with compression fittings or capillary solder fittings. Now the sizes changed again, common ones are 8, 10, 12, 15, 18, 22, and 28 mm. And of course, one needed compression fittings made for 16mm and 19mm also, so as to fit the older pipes...
That's Europe. What I have seen in the US are the commonly found so-called 1/2" copper pipes with solder fittings, this is about 16mm (5/8") in diameter, so I guess they are still using internal diameter measurements. Similarly, the so-called 3/4" pipes appear to have about 21mm outside diameter.
I guess the easiest way to turn these into metric sizes would be to redefine them as 16mm and 21mm and leave it at that. At least the traditional inch-units pipe thread sizes are roughly the same everywhere!
SIGBUS @ NO-07.308
And the metre is defined properly these days (as is the second) in terms of wavelengths of radiation.