At 15:02 22-01-01 -0800, Matt wrote:
>Charlie Bell wrote:
> >
> > > .... just reminded me to say this. I hated to watch the kids
> > > talking about cars and planes, and gaving *all* speeds, distances,
> > > and sizes using the horrible miles and inches, and soon after
> > > translating to SI. It took me a long time explaining to
> > > my daughters why that was Evil. Yikes.
> > >
> > > I hate television.
> > >
> > > Alberto Monteiro
> >
> > Explain again why it's wrong? Aren't metres and grams just as arbitrary as
> > inches and ounces?
> >
> > :o^
> >
> > Charlie
>
>They're less arbitrary. Metric has sensible definitions for each
>unit which fits nicely with the other units, which eventually ties back
>to some "universally recognizable" arbitrary measurement, like the
>diameter
>of the Earth.
Except that when they got around to re-measuring it, it turned out that
they had mis-measured the distance from the North Pole to the Equator
through Paris, so rather than being 10^-7 of that distance, the standard
for the meter became the distance between two scratches on a bar of
platinum-iridium alloy.
Now, of course, the meter is the distance light travels in 1/299,792,458 of
a second, which is defined as the duration of 9,192,631,770 periods of the
radiation corresponding to the transition between the two hyperfine levels
of the ground state of cesium-133. Nothing arbitrary about that . . .
-- Ronn! :)
