Pat:
I think in all of these discussions of cm vs mm, we are not talking necessarily
of apples and oranges. There is a case for both units - but in different
circumstances.
In the case of a particular industry (e.g. construction, or automotive), or a
particular company that has decided to go metric, there is no doubt that
sticking to mm is the only way to go. But you have here a situation where
everybody has to be singing from the same songsheet, either by industry
agreement or company edict (or both), and there may be many who do not want to
convert but are being forced to. In this case, and taking cognizance of the
kinds of measuring work that goes on in the industry or company, anything that
removes options and choice is necessary. The cm vs mm option is the kind of
choice that will slow things down and cause confusion and errors.
But in everyday 'colloquial' metric, I believe things are different, and the cm
has its place there. Yes, many people will relate it back to the inch, which
you cannot easily do with the mm. But that is the whole point of colloquial
metric - people have a choice as to whether (in their minds at least) they want
to think metric or not. And if you make it easier (in their minds) by using
something that has some sort of relationship to what they've used before, then
you have made some (albeit slow) progress, where otherwise you might have just
met a brick wall of a mindset with no progress at all.
For example, let's say you are a metric skeptic. You have a cube (not sure
what of or in what circumstance, but let's just assume that this cube exists),
and you have to find its volume. Now if the cube was 100 mm x 100 mm x 100 mm,
the average person (but especially the skeptic) would simply give up at this
point, and say the numbers are too big, don't know how to deal with them, I'll
stick to inches thank you very much, at least I will end up with some numbers I
can deal with. But change that cube to 10 cm x 10 cm x 10 cm, and that person
might well say, "Oh, that's 1000 cubic cm, I can deal with that. And isn't
that the same as a liter?" Now admittedly I chose a very specific and easy
example, but it illustrates the kind of thinking that we all do on an everyday
basis, even for those of us who are well versed in SI.
Now I know measuring cubes like this doesn't happen very often in reality, but
we are dealing with perception here as much as anything. And if people can
perceive that metric is easy (by keeping to numbers that are not too big, not
too small, in their minds), you will achieve progress that would otherwise
simply not be made. I believe that is why all the odd units were invented over
the centuries (in whatever measurement system you had), in order that the
people were comfortable with the numbers involved. This is quite different
from in the laboratory, in the drawing office, on the shop floor or on the
construction site, where the size of the numbers doesn't matter too much as
long as everyone is talking the same (and only one set of) numbers.
Different strokes.........
Cheers
John F-L
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Cc: USMA Metric Association
Sent: Monday, June 13, 2011 8:50 AM
Subject: [USMA:50607] RE: cm vs. mm
Dear Brian and Harry,
Further to my earlier email I have interspersed some remarks within your
text, in red.
On 2011/06/13, at 14:06 , <br...@bjwhite.net> <br...@bjwhite.net> wrote:
I've always thought the same thing. This whole cm vs mm thing is nonsense.
It really doesn't matter.
My skis are 168 cm....I know that's 1680 mm. I know 2.4 km is 2400
meters. Ok....we all get it. That's what makes the metric system so easy.
You are telling me several things here.
1 You are numerate and proud of your skill in moving decimal points backwards
and forwards. Unfortunately for metrication programs you belong to a relatively
small group of highly numerate people. Others do not share your skills.
In Australia, a regular survey of the numeracy of adults reports that about
half of all Australians do not have the numerical skills to hold down a job in
an office. Your planning for any metrication program should include information
like this innumeracy information from Australia. Although I don't know the data
for the USA but I suspect that it's not much different from that in Australia.
You can avoid many problems by simply choosing to use whole numbers for almost
all of your work and for your communication with other staff; see
http://www.metricationmatters.com/docs/WholeNumberRule.pdf
2 You have already developed a centimetre mindset already so it will be very
difficult for you to change this to a millimetre mindset. It will also be
difficult for you to consider metrication programs that do not follow the
centimetre path that you have already chosen. I suppose that a metrication
procedure that includes millimetres is simply not on your table to consider -
no matter how fast the process is. See
http://metricationmatters.com/docs/MetricationInADay.pdf
So--grab a 250 mL (or 25 cL) glass of wine, take a sip and relax.
As a matter of interest wine is served here in 150 mL glasses - there are 5
glasses in a 750 mL bottle.
This has to go down as one of the dumbest threads on this list yet--
centimeter hatred. Now that's rich.
Let me repeat, I do not hate centimetres.
-------- Original Message --------
Subject: [USMA:50601] cm vs. mm
From: Harry Wyeth <hbwy...@earthlink.net>
Date: Sun, June 12, 2011 9:01 pm
To: "U.S. Metric Association" <usma@colostate.edu>
Cc: "U.S. Metric Association" <usma@colostate.edu>
May I suggest that the issue of mm vs. cm is pretty low on the agenda for
moving forward with adoption of the metric system in the US?
I disagree. The key to this is concentrating on the metrication process. You
are quite right if you are approaching the metric system from the point of view
of metrology where the centimetre is quite rightly, and historically a genuine
part of the metric system and more formally of the International System of
UNits (SI). But centimetres have proven to be a key delayer of metrication
programs. You can slow down any metrication process with centimetres and that
is why I consider avoidance of the centimetre to be so important "for moving
forward with adoption of the metric system in the US?".
I know that Aussies usually refer to short measurements in mm, which is
fine. But if an American wants to order a piece of plywood cut at the lumber
yard as, say, 155 x 80 cm, I would be really pleased (I once overheard a
Kiwi--NZ citizen--asking just such a thing).
Not only fine but FAST. Australia completely changed its building industry to
the metric system between 1974 and 1976 using millimetres only. As you can see
from the example you give, the USA is still struggling to change with
centimetres - after how many years so far? Was it since Thomas Jefferson's
presidency till now?
Telling someone that an easy way to know what a cm is by referring to his
finger can be useful. Same with the distance of 10 cm or 100 mm with reference
to a palm width. I personally find it easier to visualize the size of a cat,
for example, as perhaps 40 cm long than 400 mm.
See the remarks above about the difficulty of changing mindsets. If you want
to change a company to the metric system in a single day then you have to be
aware that you are changing mindsets of people who might have low literacy
levels with even lower confidence in their capacity to handle numbers at all.
The key to adopting the metric system in the US is just to use it. It
doesn't matter if people use it incorrectly at first, or use cm instead of mm,
or even use kms instead of km, or KM, or even kph.
I absolutely agree when you say "The key to adopting the metric system in the
US is just to use it." I know of no better method. This is the main way that
about 85% of Australians were so successful in their metrication transition
using millimetres. The Australians who chose centimetres are still struggling.
This was the theme used for "Metrication in a day"; see
http://metricationmatters.com/docs/MetricationInADay.pdf
What we need is leadership from government--this has always been my
belief--
I would very much like to agree with you on this point but when you have four
year electoral cycle profound long-term issues such as the absolute importance
of measurement to all human activities rarely make it to the political agenda.
Let me share an old (one-page) letter to President-elect Obama and to
Vice-President elect Biden when they first won office. This is dated now but I
think that the thoughts are still relevant. See
http://www.metricationmatters.com/docs/NaughtinToObamaBiden.pdf
which could start with, for example, weighing mail in grams and measuring
postal packages in mm or cm and on and on.
I am not sure, and I don't have the time to check right now, but I think that
the International Postal Union is all metric and all mail from the USA has to
be converted.
My favorite easy one would be selling milk in liter dairy cartons, as
they do in Canada and Australia and probably everywhere else.
Agreed, and this change would be as simple and easy as the soft drink change
that was made so many years ago.
The cm vs. mm debates may be technically interesting,
This is true for those who study metrology without considering how their
findings might be applied (by metrication) in to the community. In my
experience, metrologists are not much interested in metrication because
metrication is not metrology.
but they ("The cm vs. mm debates") do not do much toward actually
advancing metrication.
I totally disagree with this statement. Discussions about whether centimetres
or millimetres are best to use for a metrication upgrade should be at the very
heart of any debate about how we produce a smooth, economical, and FAST
metrication upgrade for the USA.
HARRY WYETH
Cheers,
Pat Naughtin LCAMS
Author of the ebook, Metrication Leaders Guide, see
http://metricationmatters.com/MetricationLeadersGuideInfo.html
Hear Pat speak at: http://www.youtube.com/watch?v=_lshRAPvPZY
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
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