20 Apr
2002
20 Apr
'02
12:03 a.m.
> Still, what do you expect from a system of units
where one of the base
> units -- by its very name -- is clearly 1000 times something else (I am
> thinking of the kilogram, of course)
I thought the gram was the base unit, which is one
cubic centemeter of
water at 4 Celcius (when water is at its most dense).
Naa - The due historical reasons the Kilogramm is defined as
the mass of the kilogramm prototype. And when they defined the
system, they wanted to have a small thing as basic unit, but
here unable to get this done with low enough tollerance. So the
prototype is a thousand times the unit (cuts tolerances by 1000,
which is a good thing).
Also the kilogramm is, AFAIR, the last of the basic units which
still relies on a prototype and has no definition on some nature
constant. The idea with the highest possibility of success would
be to link mass over the Avogadro value to the number of atoms in
one mol of a specific element (isotop). the only problem is counting
the atoms :)
If you can come up with a way to define a kilogramm by using
fundamental constants, you'll be a scientific hero.
Gruss
H.
--
VCF Europa 3.0 am 27./28. April 2002 in Muenchen
http://www.vcfe.org/