Dear Tom,
I take exception to the expression, anti-centimeter prejudice.
As you know, I am opposed to the use of the centimetre in almost all*
practical daily calculations, but this is not on the basis of an anti-
centimeter prejudice.
My opposition to the centimetre is based on observations of
metrication transitions. I simply observed that metrication using
millimetres can be done quite quickly, smoothly, and with so little
cost that savings are made almost as soon as you begin the metrication
process. On the other hand, the attempts at metrication using
centimetres are slow – painfully slow, rough – often involving bitter
disputes about the 'right' way to go about metric conversion, and so
expensive that these metric conversion attempts are often abandoned
with the thought best expressed as: 'Never again!'
As you may recall, I did not understand why it was so much better to
choose millimetres rather than centimetres for your inevitable
transition to the metric system, so I involved myself in any debates
and discussions that I could to collect the arguments both for and
against millimetres and centimetres that I could find. My collection
of these thoughts is available from http://www.metricationmatters.com/docs/centimetresORmillimetres.pdf
and I know that it is rather long because I tried to be exhaustive
to be fair to both sides of the argument.
* I sometimes – rarely – use centimetres as the basis for cubic
centimetres to get the volume of things like a home aquarium in
millilitres. However, this does not justify, in my opinion, condemning
an entire nation to something like 100 years of metric conversion
using centimetres when I have seen the the whole job done in a day
using millimetres. As you know the USA were world leaders in
measurement reform from the 1770s to the 1790s but they have not yet
succeeded in fully adopting the decimal metric system that they had
played such a big part in producing. See http://metricationmatters.com/USAmetricsystemhistory.html
for a short summary of this history
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
different trades, crafts, and professions for commercial, industrial
and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com
for more metrication information, contact Pat at pat.naugh...@metricationmatters.com
or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
On 2009/07/30, at 9:10 PM, Tom Wade wrote:
It is good of you to promote metric height numbers.
However, I do not like centimeter.
I want schools to stop teaching and using centimeter.
I also want schools to stop teaching inch-pound numbers.
So, I want height to be in millimeters.
What is it with the anti-centimeter prejudice that many people have
on this group ?
Just because mm are more appropriate for nearly all industrial use
doesn't mean the humble cm doesn't have a role. To place cm
alongside inch-pound as in the above paragraph is way over the top,
and to try and pretend that that units between kilo and milli don't
exist is to miss out on a huge advantage of the use of metric
prefixes: the ability to scale the unit to the most appropriate size
(and to advocate not teaching a unit that is not only officially
recognized but is in wide use internationally simply because purists
have a dislike of them is to recommend leaving holes in young
people's education).
The fact is that cm *are* the most appropriate unit for people's
height. If you don't like using cm, then quote your height in
meters (which is effectively 'hidden centimeters' as you will
typically quote it to two decimal places, i.e. centimeters). Thus
the centimeter is the unit that is closest to the required precision
for people's height. It also gives a nice manageable range of whole
numbers.
My height is 174 cm or 1.74 m. If I am writing it down, I may write
'1.74 m', but in saying it, I will say "one seventy four" without
any units, which can be understood as one hundred seventy four
centimeters or 1 meter plus 74 centimeters.
Quoting height in millimeters is simply plain stupid - height is
never expressed with that precision, as something as simple as a
haircut will change your height. People who insist on using mm for
height are like people who are so impressed with a screwdriver as a
tool, that they think it can be used for everything (whereas a less
generally useful tool such as a hammer would be more appropriate for
*some* applications). I doubt very much you will see mm being used
for height in countries where metric is the system used. Also,
using mm for height gives an unnatural feeling, rather like the
putative "New York 96.56 km" sign that anti-metric activists insist
would replace a more natural "60 mile" sign.
As for the choice of using meters or centimeters, I would point at
that the use of centimeters has the advantage of yielding a whole
integer without the need for decimal places -- something that is
often (quite correctly) pointed out by people recommending the
advantages of mm over inches or centimeters in other applications
such as engineering drawings. Why not apply the same logic here ?
Use the unit that is best suited to the range and precision required
by the application.
Tom Wade
