In case anyone is worried.
Me, I’m in the US, and we don’t mess with metric unless we’re buying soda. I wonder if the pound is suffering as well?
You gotta register to get to the page, but it’s free. And, yes, that is odd. I thought it already was defined by a certain number of atoms of some element. Silly me.
Ha! Good! Oh, we still use the Imperial system, we must be weird! At least the pound is still a freakin pound!
Ah-ha, so we aren’t gaining weight after all, it’s just that the killogram is getting lighter. More pudding please matron.
Perhaps they should talk to a porn production company and ask if they can hire some of their fluffers.
I thought they had switched to a chemical definition for the kilogram now.
Eh, kinda sorta. We have this definition that Avogadro’s number of C-12 atoms weighs precisely 12 grams. Unfortunately, this just defines Avogadro’s number. The kilogram is still the (apparently not-so-standard) mass.
Personally, I think it makes a lot more sense to say, by fiat, that Avogadro’s number is (some really big number) and use this to define the kilogram, but eh, whadaya want?
The kilogram is still defined by an artifact. The same artifact what’s now shrinking, in fact. The meter is defined relative to the velocity of light and the second is defined relative to the rate of spontaneous transition between two ultrafine states of a certain Cesium isotope, but the kilogram is still a hunk of platinum-iridium alloy sitting in a vault in Freedonia … er, France.
I thought a kilogram equaled one liter of water.
I wish they would. This has always made me uncomfortable. Maybe this will change their minds.
Oh, and people who are pleased in the stability of a pound, give yourselves a big old :smack: - the pound is defined as 0.45359237 kilograms, so whatever fate befall the kg hits the lb as well. 
I’ve been doing the conversion of 1kg=2.20462#(avdp).
Have I missed something during a long nap?
I think that’s a convenient rule of thumb, not a definition.
^^ I had the same idea, since 1 cc of water = 1mg; I had always assumed it was an exact measurement.
Heh. And they say you can’t learn a thing sitting on your butt reading the internet all day…
After consulting one of my ready references, it’s mighty close:
Pure water, specific gravity of 1.00, weighs 999.6 kg/m³, so that should bring out the weight of 1 liter to be 999.6 g, or a snitch shy
of 1 kg.
It remains a convenient rule of thumb, however. And note that this depends on the temperature, as well, since the density of pure water depends on how warm it is, right?
I wonder why the kilogram standard is shrinking? I have two theories:
-
Radioactive decay due to unstable isotopes of iridium or platinum.
Are you volunteering to count out 6.022 x 10[sup]23[/sup] atoms the next time we need to weigh something?
Metrology is just cool, in my opinion. There was an article in “Equinox” (Canadian science mag) about Canada’s chief metrologist a couple of years ago. He’s the guy responsible for Canada’s two copies of “le grand k”. The article was fascinating just for the details it provided about the amount of crap he has to go through to use these copies of the standard kilogram; i.e., only taking them out of the vault on weekends, to minimize the effect that vibrations from car traffic have on the super-sensitive scales.
Actually, it’s 6.02214199 x 10[sup]23[/sup] according to NIST. 
Oh lord, somebody’s gonna start talking about moles now aren’t they. From there, it can’t be much longer before Planck’s Constant comes up and from there, it’s only a hair’s breadth leap to Schroedinger’s darned cat!
RUN AWAY!! RUN AWAY!!
