Dear Pierre, Bill, and Robert,
I have interspersed some remarks in red.
On 2009/11/30, at 01:48 , Pierre Abbat wrote:
On Saturday 28 November 2009 14:15:05 Bill Hooper wrote:
On Nov 28 , at 1:49 PM, Robert H. Bushnell wrote:
Conversion from inch-pound units to metric
units may be used as examples in algebra.
In my opinion there are better examples that don't muddy the
measurement waters with conversions. I am a fan of the Otis Elevators
approach where they identify all jobs as old or as new; they then
identify each job as whether it is a new design and construction or a
repair job to an existing elevator. Obviously the words, old-new, new-
new, and new-old were immediately confusing so they used color codes:
red and blue for existing foot-pound equipment and green and gold for
new metric equipment. They then had four possibilities so that all
work could have a color code:
Red = repair of existing equipment in feet and pounds
Blue = new work to be done in feet and pounds
Green = new work to be done in metric
Gold = repair of existing metric equipment in metric
Obviously the company were planning for a transition period that might
last 100 or more years (elevators are long-lasting) but most
importantly nobody has to do any measurement conversions – in any
direction. Workers simply used feet and inches tapes and rulers for
work that was fitted many years ago and had a old measures tool box of
wrenches etc. for this work. For metric jobs they simply use their
metric tool box with millimetre only rulers and tapes.
The key point for this company is that they have no need of
conversions. No conversions means no conversion mistakes with
considerable savings for the company (possibly around 10 % of turnover).
There is no good reason to teach conversion from inch-lb to metric.
I agree and go further. There is probably no good reason to teach any
conversions at all for almost all students (see next response).
I disagree. If all new surveys are labeled in meters, surveyors will
be
working with old maps and deeds labeled in feet and chains for at
least
another hundred years. Not everyone will need to convert, but there
are
enough specialties where it is needed that it should be taught.
I suspect that Bill and Robert are talking about students in a general
sense and that Pierre is writing about specialist students who are
being trained to carry out a highly specialised task. I can see a
reason for the specialist training but no reason at all for the idea
that all students in a (say) grade four elementary school class should
be taught to do conversions of any type.
Students should not be taught conversion of pounds, until they have
demonstrated that they can multiply two eight-digit numbers by hand
accurately. If they can multiply two three- or four-digit numbers,
they may
be introduced to feet and inches. To be introduced to the survey
foot, they
must be able to do long division by hand with an arbitrary four-digit
denominator.
You are talking about a high level of numeracy here – probably less
than 5 % of the Australian population would be able to meet your
criteria. See http://www.abs.gov.au/AUSSTATS/[email protected]/Latestproducts/4228.0Main%20Features22006%20(Reissue)?opendocument&tabname=Summary&prodno=4228.0&issue=2006%20(Reissue)&num=&view=
for details, where they write: 'On the numeracy scale, approximately
7.9 million (53%) Australians were assessed at Level 1 or 2, 4.7
million (31%) at Level 3 and 2.4 million (16%) at Level 4/5. On the
problem solving scale, approximately 10.6 million (70%) Australians
were assessed at Level 1 or 2, 3.7 million (25%) at Level 3 and
800,000 (5%) at Level 4 (table 1).'
They also write elsewhere: 'To assist with interpreting the results,
Level 3 is regarded by the survey developers as the "minimum required
for individuals to meet the complex demands of everyday life and work
in the emerging knowledge-based economy'
Conversion shall be done with the definitions of units. When
converting
pounds-force to newtons, for instance, the approximate factor 4.448
must not
be used. One must use the exact definition of the pound and the
standard
acceleration of gravity.
Agreed, keeping in mind that the current definition of an inch, a
foot, and a pound are just that – current – they have changed over the
years so any historical documents need to know the historical timing
and the historical place where the old pre-metric measuring words came
from.
Pierre
--
lo ponse be lo mruli po'o cu ga'ezga roda lo ka dinko
Cheers,
Pat Naughtin
Author of the ebook, Metrication Leaders Guide, that you can obtain
from http://metricationmatters.com/MetricationLeadersGuideInfo.html
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
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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
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