On Mar 7, 10:32, Geoff Roberts wrote:
>
> ----- Original Message -----
> From: "Sean 'Captain Napalm' Conner" <spc_at_conman.org>
> > It was thus said that the Great FBA once stated:
> > >
> > > >Essentially, this means that 1 Litre of pure water weighs 1Kg and
> is
> > > >where the basic units came from.
> > >
> > > 1 Litre will also fit quite nicely in a cube 10cm a side.
> >
> > At 4 degrees Celcius at sea level, don't forget.
Since we're getting all accurate again, ..
The kilogram was defined in a way intended to represent the mass of one
cubic decimetre of water at its maximum density, and to this end a suitable
platinum-iridium cylinder was constructed to be "the standard". But it was
later found to be slightly inaccurate, so the definition of the standard
was redifined to be the mass of the cylinder. Thus 1 litre doesn't *quite*
fit into a cube 10cm a side, being 28 ppm too large :-)
In 1964 the litre was redefined for practical purposes to equal a cubic
decimetre, but not for work of high precision.
An imperial gallon is defined in terms of a mass of water (weighing 10
pounds at a density of 0.988859 grams per cc, ie at 20C, in air at a
certain density, against weight of a certain density, all stated in metric
units!).
> > -spc (Atmospheric presure is measured in millibars, right?)
>
> Correct. The ISA (International Standard Atmosphere) is 1013.2
> hectopascals (equiv - millibars) _at_ 20C (hmm or is it 15? been a while
> since I did Met.)
15C.
--
Pete Peter Turnbull
Network Manager
Dept. of Computer Science
University of York
Received on Wed Mar 07 2001 - 03:03:01 GMT