[time-nuts] 15 ns vs. 15 nS

John Day johnday at wordsnimages.com
Tue May 22 09:02:36 EDT 2007


At 08:26 AM 5/22/2007, you wrote:
>I was basing my observation on the three fundamental units - M, K, & S, as
>taught in the 60's. Just goes to show how things have changed...

You mean the old MKSA system? I was taught that in high school too, 
after we abandoned the cgs system. But I was in Australia at the 
time. Metric conversion started there in 1970 (I was in college by 
then), SI was introduced to primary schools in 1972 and to high 
schools in 1973. For all practical purposes, conversion to SI was 
complete by 1976.

So having started out with the centimetre, gramme, second system, 
moving to the so-called 'rationalised' metre, kilogramme, second, 
Ampere system the move to SI at university seemed trivial. The really 
difficult thing has been to move to a partially metricated country in 
my 50's. Trying to delve back into the recesses of my teenage years 
to once again work in pounds at the food store has not been fun! Here 
in Canada it seems that we are legally required to show prices in the 
store in both, or at least it is customary to do so, but ask for 
something in metric quantity in many smaller stores and it suddenly 
seems I have grown an extra head or two overnight. At least my 
butcher now has a scale that will work in metric units!

John

PS: Don't get me started on trying to deal with US Customary measure 
when living there in the 70's! Little did I realise that a gallon was 
not really a gallon after all.

J


>Rob
>
>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>Behalf Of John Day
>Sent: 22 May 2007 12:43
>To: Discussion of precise time and frequency measurement
>Subject: Re: [time-nuts] 15 ns vs. 15 nS
>
>At 04:05 AM 5/22/2007, Rob Kimberley wrote:
> >As Seconds are a fundamental unit of the SI system, shouldn't the "S"
> >be upper case?
>
>Of seven SI 'base units' only two - K for thermodynamic temperature and A
>for electrical current are capitalised. On the basis of your suggestion we
>would need to campaign for a change in 5 units, not just one.
>
>John
>
>
> >Over to you fellow "nuts".
> >
> >Rob Kimberley
> >
> >-----Original Message-----
> >From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> >Behalf Of James Maynard
> >Sent: 22 May 2007 08:26
> >To: Discussion of precise time and frequency measurement
> >Subject: [time-nuts] 15 ns vs. 15 nS
> >
> >Didier Juges wrote:
> > > Sorry, it's not 15nS rms, it's 15nS at 1 sigma.
> > >
> > > Didier KO4BB
> > >
> > >
> >A long s we are being pedantic:
> >15 ns = 15 nanoseconds, but 15 nS = 15 nanosiemens.
> >
> >I am sure in the time-nuts list, we are concerned with nanoseconds, not
> >nanosiemens!
> >
> >
> >
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