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Metrication matters - Number 79 - 2009-12-10

You can read all previous issues at /newsletter if you scroll own to the bottom of the page. You can also check the metrication matters web page at http://www.metrictionmatters.com.htm

Metrication matters is an on-line metrication newsletter for those actively involved, and for those with an interest in metrication matters.

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Dear Subscriber,


1 Feedback - notes and comments from readers 2 Editorial 3 Oddities - measurements from around the world 4 Tips - pointers and methods to make your measurements easier. 5 Signs of the times 6 Quotations 7 Q&A - readers' questions and answers 8 Rule of thumb 9 History 10 Hidden metric

1 Feedback

Mike Joy wrote:

Hi Pat,

How's things these days? I expect you're getting more and more accolades for your great Metric Matters newsletter as time goes on.

Can you answer me one thing please?

What are the other cross-relationships in the metric system, like the water/weight example (i.e. one cubic decimetre of water equals one kilo)?

Best wishes,


I usually see the example Mike gives as '1 litre of water has a mass of 1 kilogram'.

Other examples that spring to mind are

  • A millimetre of rain falling on a square metre of our roof puts 1 litre of water into our rainwater tank. (Here in dry Australia that's important).

  • Along the same lines, a millimetre of rain on 1 hectare of land puts 10 000 litres of water into the soil or into a farm dam once the soil is saturated.

  • Water boils at 100 °C and freezes at 0 °C.

  • A cubic metre of air has a mass of 1 kilogram in Boulder Colorado, which is 1655 metres above sea level (I think I learned this from Robert Bushnell). Air at sea level is a little denser at 1.2 kg/m3.

  • The pressure of the air at sea level averages about 100 kilopascals.

  • You use one joule of energy when you move (say) an average apple (weight = 1 newton) from the floor on to a one metre high bench.

  • The atmosphere is about 100 kilometres deep, so space starts 100 kilometres above the Earth.

  • The troposphere extends a little more than 10 kilometres above the Earth. Most of the Earth's weather occurs in the troposphere, which contains 75 % of the Earth's atmosphere and 99 % of the Earth's water vapor. See http://www.physicalgeography.net/fundamentals/7b.html

  • From the equator to either of the Earth's poles (North or South) is very close to 10 000 kilometres.

  • An electric current of one ampere is flowing in a circuit when one coulomb of charge passes in one second.

Mike Joy and I would both like to see more of these neat, relatively easy to remember, reference values that use metric values or metric approximations. If you would like to add to this collection, please email and I will add your contributions to future editions of the Metrication matters newsletter.

Han Maenen from the Netherlands wrote to the USMA maillist (http://lamar.colostate.edu/~hillger/listserv.htm ) to say:

Once I was reading English (!!!) newspapers dated between the two World Wars in our University Library and in ads for cars the wheel sizes were given in millimetres. That inch stuff came in after World War Two.

Han Maenen

2 Editorial

Some nations, industries, companies, work groups, and individuals have used fast, efficient processes for their inevitable metrication upgrade and some have decided to use slow, inefficient, and costly metrication processes for their inevitable metrication upgrade.

For example, the USA, since about 1780, has consistently chosen the slowest possible methods for their inevitable upgrade to the metric system. Here is my take on the five most important mistaken beliefs for the slowest possible methods used by the USA over the last 200 or so years:

1 Holding the belief that the metric system is based on 10s.

This belief was current when Benjamin Franklin and Thomas Jefferson successfully promoted the idea of a 'decimal' metric system in the 1780s and 1790s in France, but modern world practice is to fully use the prefixes of the metric system so that there is no need for fractions – vulgar or decimal – at all. It's probably fair to say that the modern metric system is based on 1000s because the prefixes hecto, deca, deci, and centi are rarely used by world leading industries. An example is the soft drink industry in the USA where small quantities are specified in millilitres, larger quantities are in litres, and very large quantities (in the bottling factory) are in kilolitres or cubic metres – at no stage is there any need for fractions.

2 Teaching decimal fractions

Children spend countless millions of hours sliding decimal points back and forth to support the teaching of decimal fractions. Decimal fractions should not be taught as part of measurement, as generally speaking, fractions are avoided in manufacturing industry. At its best measuring is taught with practical applications of measurement in whole numbers using one measuring unit at a time. The best way is to pick a unit with a prefix that will provide the student with whole numbers and then stick to it. For example to lay out neat, tidy, and presentable school work at all levels, from about Grade 3, the best way is to use millimetres – only. Use millimetres for line spacing, millimetres for margins, millimetres for drawing sizes, and millimetres for drawing components. As there are no centimetres in this work, then no decimal fractions, no halves and quarters of centimetres, and no conversions are ever necessary.

3 Using centimetres.

Using centimetres always leads to massive delays. I have observed a metrication upgrade that was done in a single day using millimetres, and I have seen metric transitions that has taken well over 100 years so far using centimetres. I can't help noticing that there is a very costly difference between these two approaches. By the way, I have never seen, nor heard of, a rapid transition to the metric system using centimetres.

4 Believing that the government needs to do something.

This is an odd belief that is not supported by observed fact. Almost always progress is made toward metrication by the action of an individual. Examples in the USA include: the metrication of wines, spirits, and beer; the metrication of soft drink containers; and the metrication of cars, trucks, tractors, motor bikes, and computers that all happened without any noticeable positive leadership from politicians.

5 Finally, believing that metrication must be slow

The belief that learning the metric system is such a slow process that it needs years of teaching in formal educational establishments when the truth is that enough of the metric system for 99 % of all human activities can be taught in about a minute. The consolidation of this knowledge so that it will be remembered for the rest of your life takes about an hour. And spending about a day refining this knowledge can make you a metrication leader – there need be nothing slow about it – slow means you have chosen the wrong process for your metrication upgrade.

To see details of how these five beliefs can be overcome, refer to 'The metrication Leaders Guide' that you can obtain from: /MetricationLeadersGuideInfo.html

3 Oddities

Some schools in the USA are now using mathematics text books from Singapore according to Wikipedia (http://en.wikipedia.org/wiki/Singapore_Math_Method ):

They have become more popular since the release of scores from the Trends in International Mathematics and Science (TIMSS) Study showed Singapore at the top of the world in 4th and 8th grade mathematics.

Notably, the Singapore Math Books make mathematics easier to learn as they only uses metric system (SI) units. There are no Imperial measuring words or any old pre-metric measuring words from the USA. Probably best of all for the direct teaching the metric system there are no conversions. See /metric_conversion.html

4 Tips – pointers and methods to make your measurements easier.

This is a repeat mnemonic device to remember a close approximation for the diameter of the Earth. Write down the numbers 1 and 2 like this, 12, then leave a space; after the space write down the numbers 3 and 4 so that you now have 12 34. Working backwards add 4 to 3 to total 7 and place the number 7 in the central space. Your estimate for the diameter of the Earth now reads 12 734 kilometres. (By the way 12 734 x π = 40 005 kilometres).

5 Signs of the times

In the year 2009, the New York State Weights & Measures law (Article 16, Sec. 176) declares metrication to be:

'of vital importance to the economy of the state.'

6 Quotation

Tell people something they know already and they will thank you for it.
Tell them something new and they will hate you for it.
George Monbiot

7 Q&A


What effect does metric system education have on employment opportunities?


Let me quote from an article from the 'Rhode Island news' at http://www.projo.com/news/content/BIOTECH_WORKFORCE_SKILLS_11-30-09_F3GH1B6_v19.38acbe6.html where they write (bold emphasis added):

There are 73,700 Rhode Islanders out of work, but leaders of one emerging industry — bioscience — say they can’t find enough qualified applicants to fill vacant jobs. ...

One of those companies is Biomedical Structures, in Warwick. The company has 18 employees and makes textile-based devices designed to be implanted into people, used for everything from rotator cuff-repair to pelvic-floor reconstruction.

John Gray, president, said that for every four job seekers who apply for work at his company, only one is suitable for employment.

Gray said the company trains workers for specific jobs, but there are certain qualities the company seeks, such as the ability to work in the metric system, a capability for highly precise documentation, and the right mindset to work in a “clean room” where the slightest contamination can be disastrous.

Those workers are hard to find, said Gray.

Note that 'the ability to work in the metric system' is the first criteria mentioned.

8 Rule of thumb

It's no wonder that so many people believed the old fallacy about the Earth being flat for so long; the Earth only curves downwards because of its spherical shape at approximately 80 millimetres per kilometre. That's roughly the width of the palm of your hand.

9 History

Han Maenen, from the Netherlands, wrote to the USMA to report that the book, Outline of the Evolution of Weights and Measures and the Metric System by Hallock and Wade, New York 1906, had been digitised and placed on the public domain at: http://www.archive.org/details/outlinesevoluti00wadegoog

I was immediately struck by a reference to a Chinese traveller, Hiuen Tsiang (603-668), who described Indian measurements as follows:

In point of measurements, there is first of all the yojana; this from the time of the holy kings of old has been regarded as a day's march for an army. The old accounts say it is equal to 40 li; according to common reckoning in India it is 30 li, but in the sacred book (of Buddha) the yojana is only 16 li. In the subdivision of distances a yojana is equal to eight krosas (ken-lu-she): a krosa is divided into 500 bows (dhanus): a bow is divided into four cubits (hastas): a cubit is divided into 24 fingers (angulis): a finger is divided into 7 barley corns (yavas): and so on to a louse (yuka), a nit (liksha), a dust grain, a cow's hair, a sheep's hair, a hare's down, a copper water (a small hole in a copper cup for water administration), and so on for seven divisions, till we come to a small grain of dust (anu): this cannot be divided further without arriving at nothingness, and so it is called the infinitely small (paramanu).
Some historians regard this attempted organisation of measuring words as a system. It is probably better to regard this simply as an attempt to provide some sort of credibility to these old measuring words as they obviously had no standard definitions to provide them with any secure foundation. It is probably better to think of the metric system as the only measuring system that ever existed, and that all previous collections of measuring words were just that – previous collections of measuring words.

I have added this item, and many others to my Metrication timeline page at: /docs/MetricationTimeline.pdf

10 Hidden metric

About a year ago, I wrote to the Apple Computer company to ask why they engineered in metric units and then dumbed down their design and construction work to inches for the public in all nations even those that have used metric units – only – for many years. You can read a copy that I sent to the USMA here:

Stan Jakuba, a professional engineer, responded to the fact that I had used the word, centimetre, as follows:

Pat: There may be a misunderstanding. No respectable company in the world can use cm in design and manufacturing because it is against the guidelines of their respective professional societies. Design and drafting in manufacturing has been unified on the mm for a century. Civil engineers, the last stronghold of cm, yielded a 1/2 century ago. Professionals, that is.

I would not be concerned about Apple D&M. The writer of the article probably just failed to distinguish between D&M documentation and documentation for public consumption; there the cm continues.

Stan Jakuba

I thank Stan for his comments. I had no reply from the Apple Company.


Pat Naughtin

Geelong Australia

Pat Naughtin is a writer, speaker, editor, and publisher. Pat has written several books and has edited and published many others. For example, Pat has written a chapter of a chemical engineering Encyclopedia, and recently he edited the measurement section for the Australian Government 'Style manual: for writers, editors and printers'. Pat has been recognised by the United States Metric Association as a Lifetime Certified Advanced Metrication Specialist.

Pat is the author of the e-book, Metrication Leaders Guide, that you can obtain from /MetricationLeadersGuideInfo.html

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