# [ RadSafe ] SI; Now or never?

Peter Thomas Peter.Thomas at arpansa.gov.au
Sun Feb 19 16:21:15 CST 2006

```Hello All,

Here in Australia we live in a somewhat more metrified version of the
two worlds.  I was fixing one of my kids bike the other day and had the
spanners (read wrench in North America) out, my set has metric on the
right and fractions of an inch on the left.  We've just had an
anniversary of sorts, February 14, 1966 was when Australia switched from
pounds shillings and pence to dollars and cents.  I'm not sure where
this fell in the metrification process (I was born in 1968) but I
understand most of it happened in the late 60s and early 70s.  My
generation has really only known the metric system, except that we still
tend to think of a person's height in feet and inches; weight in
kilograms is normal, except for babies, the hospital staff will write it
down in grams but if you want to tell anyone you need to convert to
pounds and ounces.  Another one that struck me a few days ago and seemed
to coincide with the start of this thread was when I stopped at a petrol
station to fill up and check my tyre pressure, I punched in 36 psi on
the control panel of the air hose and then had the thought that I had
basically never thought of that measurement in kilopascals.

On another tack, I happened to be at elementary school in the USA in
1979 and I can remember lots of metric stuff, including TV ads featuring
where our hero is chasing a villain and both stop at a gas station
whereupon the villain nearly escapes because he fills up with 10 gallons
and hares off while Litre Leader is arguing with the attendant about
getting 40 litres.

Rainer brought up the Mars mishap, I'd venture that this is the Mars
Climate Orbiter, lost in 1999 due in part to the use of pound units for
force in a computer program.  Wikipedia has a succinct summary at
http://en.wikipedia.org/wiki/Mars_Climate_Orbiter

Peter Thomas
Medical Physics Section
ARPANSA

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