|
![](/i/fill.gif) |
Warp schrieb:
>> That's because the /initial/ definition of the kilogram was one liter of
>> pure water at /zero/ degrees celsius.
>
> At zero? I don't think so. At zero celsius water freezes, after which one
> litre of it weights a whole lot less than one kilogram.
I was indeed slightly mistaken: The original definition was for water at
the /melting point/, which is a bit above 0 degrees C (something like
0.01 degrees C, IIRC).
>> And yes, a /change/ of 0.003% would be a /tremendous/ catastrophe.
>
> To what?
To everyone requiring such a precision in /any/ physical unit derived
from the kg.
I already mentioned how small the "drift" of the Prototype is - and yet
scientists are worried about this, so /someone/ seems to be relying on a
precision in that order of magnitude.
And after all, there is no reason whatsoever to redefine the kg in a way
that "breaks backward compatibility": Whatever phyiscal properties you
base it upon, you can always add some factor to the new definition to
make it match the previous definition.
Post a reply to this message
|
![](/i/fill.gif) |