On 2009/10/08, at 14:40 , Aaron Harper wrote:
Having a student have to figure out how to get from one unit to an
equivalent unit in another system
Dear Aaron,
I am having trouble with your line, 'Having a student have to figure
out how to get from one unit to an equivalent unit in another system
…' as I know of only one system of measurement.
And I am also sure that only one system of measurement has ever existed.
When the decimal metric system was developed from Wilkins universal
measure in the 1790s, it became the world's first measurement system.
Subsequently this first idea for a measuring system evolved from the
decimal metric system through the simpler name of metric system to the
International System of Units (SI).
As you know this is a complete system of units that is able to measure
everything from the smallest to the largest things in the entire
Universe. As Condorcet put it in the early 1790s, the decimal metric
system is:
'for all time; for all people'.
I am aware that there were subsequent refits of bits and pieces of
various small groups of old measuring words. The UK tried to develop a
decimal currency based on 10 florins to a pound in about 1824 while
they held to the idea of 24 pennies to a florin.
Some scientists tried to copy the coherent properties of the metric
system with their foot-pound-second "system" and the foot-poundal-
second "system" while some engineers tried to do the same with their
foot-slug-second "system"; all done while the foot changed its length
in, at least, these years: 1824, 1834, 1855, 1893, and 1959. I find it
impossible to recognise these attempts as comprehensive or universal
measuring "systems".
The point that I want to make is that it is not possible to convert
from one system to another system when there has only ever been one
single system – the metric system – that is formally known as the
International System of Units (SI). All the rest are just more or less
random collections of old pre-metric measuring words.
Now let's consider an actual conversion problem.
Convert ten yards into metres.
This problem should not even be attempted until you answer this
question:
Which yard do you mean? Are you talking about the 1859 metric-defined
international yard, the 1893 metric-defined yard, (the statute yard or
the survey yard of the USA), the interim yard between 1834 and 1855
based on the length of a pendulum with no real fixed length, the 1855
UK yard based on an artefact, the 1824 UK Imperial yard (1832 in the
USA) that got burned with the UK Houses of Parliament in 1834 or one
of the many earlier yards that appeared from time to time all with
slightly varying lengths (possibilities here are three Elizabeth I
feet, the Edward I ulna, or three Roman feet, etc.)?
If you don't ask all of these questions you infer that there are two
"systems" metric and only one other, when the facts are that there has
only ever been one system – the metric system as stated above – and
all of the other old hodge-podge of measuring words with multiple
definitions that have varied through time.
Hhhrrrmmmph!
P.S. Apologies for being so grumpy – you've hit a pet peeve!
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
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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,
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