Let us get metricized!

(Posted on 20th May 2015, the 140th anniversary of the Metre Convention was signed)

I am happy to join with you today in what will go down in history as a demonstration for the unity of the system of units in the world.

One hundred and forty years ago, representatives of seventeen nations signed the famous Metre Convention in Paris. This treaty set up the institute for coordinating the development of the metric system. In this treaty it says that the unit of length is m, the mass unit is kg, and the time unit is s. After this convention was signed, more and more nations joined gradually, which means the new metric system is widely spread among nations and becoming so universal in the world. In 1960, at the 11th meetings of the CGPM, the system of units it had established was overhauled and relaunched as the "International System of Units" (SI). After that, SI is widely used in the international communication. Now SI is used all over the world, and everyone in the world uses SI in international communication. It is known to all that SI brings convenience to everyone.

But 140 years later, there are still some people do not know the meaning of using SI. 140 years later, they still use the obsolete system of units in international communication. 140 years later, some of them says that they "do not know SI". 140 years later, some even refuse to use SI. And we come here today to talk about this problem.

In the past the units varied from nation to nation in Europe, which severely hampered the communication among nations. And France is not an exception either, so people need a new system of units which is "for all people for all time". To define the new unit, the French Academy of Sciences commissioned an expedition lasting from 1792 to 1799, which measured the distance of the meridian, was to serve as the basis for the length of the quarter meridian connecting the North Pole with the Equator. Then the 1/10000000 of the meridian is defined  as 1 metre. After metre was defined, litre and gram was defined as well. The new metric system is decimal, so it is very easy to use. And then more and more nations started to adopt it. Then in 1875 the Metre Convention was signed, which is the beginning of the unity of the units. And in 1960 SI is launched by BIPM, which is a universal system used all over the world.

However, there are some people still sticking to the obsolete unit system in international communication, which made other people confused. But we refuse to believe there is no hope to these people. We refuse to believe that these people cannot to change. And so, we come to tell these people about using SI and the meaning of using it.

We have also come to this spot to remind these people of the urgency for now. There is no time to refuse the coming of SI. Now is the time to make real the promises of metrication. Now is the time to stop using the obsolete units. Now is the time to let us get metricized. Now is the time to make the using of SI a reality for everyone.

It would be fatal for the people to overlook the urgency of the moment. If  you have ever read "A Day's wait", you will know that the 9-year-old boy thought he would die just because of the disunity of the units.  In addition, the conversion of different units will be hard, sometimes it is even critical. If you are converting units too often in international communication, it will be very messy, and converting units will bring errors sometimes. In short, we should use SI directly instead of converting to it.

But there is something that I must say to those people, who stick to the obsolete system now: We must think about the other people. If you are still using those units, not only do you bring inconvenience to others, but also you are trying to turning the clock back, which is useless. SI is used everywhere, and no one can get rid of it. We must attach significance on the unity of units.

Maybe some people do not realize the importance. They think using obsolete units on the Internet is also ok. However, this is completely wrong. Internet is for everyone in the world, not for a specific nation. That means what you sent will be spread all over the world. If you do not use SI, other people will not understand what you are saying. Sometimes it will cause misunderstanding. So following the international practice on the Internet is very vital for everyone.

We cannot walk alone.

And as we go for SI, we must make the pledge that we shall always go ahead.

We cannot turn back.

There are those who are asking about the metrication, "When will it end?" It will never end as long as some people do not use SI in international communication. It will never end as long as the manufacturers do not use SI in designing and producing. It will never end when non-SI units are still being widely used in trades. It will never end as long as metric products are not very common in the market. It will never end as long as scientists do not use SI in researches. No, no, It will never end, and it will never end until SI units can be seen everywhere and known to everyone.

I have known that some of the excuses for those people rejecting SI now. Some people say they do not know SI. Some say they cannot find SI units in life. Some even say they do not use SI. These have been a great barrier in metrication. Continuing to work with these obsolete units is equal to closing the door to the world. If you are still rejecting SI with such excuses, Look at what other people using SI, knowing that somehow this situation can and will be changed.

Let us say no the obsolete units and get metricized, I say you today, everyone.

And so even though we face the difficulties of today and tomorrow, metricizing is still not so hard for us. Just do as the following:

First, use SI in your life. Choose the tape measures, thermometers, cooking stuff, etc. in SI units and use them in your life. Buy products in SI units, even though it is expensive. You will learn a lot about  SI gradually in your own life by doing so. In this progress, do not miss the old units, do not convert, use SI only, and you will soon know about it.

Then, promote SI to other people actively. When you know how to use SI correctly, it is time that you promoted SI to others. You can discuss the benefits of using SI to others, and promote SI in any volunteer activities you do. You can also volunteer to coach or tutor metric at local science fairs or high schools if you can. To promote SI, you should describe SI units visually instead of converting to other units on request, and people will accept SI by themselves.

Last but not the least, let the officials support our activity. To do this, you can write to elected officials supporting metric legislation and opposing anti-metric legislation, to media supporting SI and explaining its benefits, to manufacturers praising them when they use SI products and use SI properly, and to manufacturers educating them when they do not use SI appropriately. When engaging in trade, state that you prefer your product or service in the SI because it is the legally preferred system of measurment for trade, according to the Convention of Metre. Then, when you see misuse of SI, write to the responsible organization. If you think you can do this, you can try. If everyone do this actively, promoting SI is not very difficult.

This is what we are doing, and this is the faith that I promote the SI with.

With this faith, we will be able to get together by using SI. With this faith, we will be able to abolish those obsolete units in international communication and follow the international practice. With this faith, we will be able to work together, to discuss together, to communicate together,  to struggle together , to stand up for SI together, knowing that we will success on getting metricized one day.

And this will be the day -- this will be the day when everyone in the world will be able to say this with new meaning:

"The metric system is for all people and for all time."

And if the whole world is to be together, this must become true.

And so let us get metricized together!

Let us use m, cm, mm, km … for length!

Let us use m², cm², ha, km² … for area!

Let us use m³, cm³, l, ml … for volume!

Let us use g, kg, t … for mass!

Let us use K, °C for temperature!

But not only that:

Let us use m/s, km/h … for speed!

Let us use N for force and N m for torque!

Let us use J, kJ for work/energy/heat and W, kW for power!

Let us use Pa, kPa, bar … for pressure!

For everyone here, let us use SI units!

And when this happens, and when we realize the meaning of metrication, when we let us get metricized from everywhere in everytime, we will be able to speed up that day when everyone in the world,wherever they come from, whatever they do, whoever they are, will be able to use SI in international communication and say this famous motto by Condorcet together:

        

        --The metric system is for all people and for all time!

Things you can do to promote SI

As is known to all, SI was published in 1960 by BIPM. SI has so many benefits as more and more countries/regions adopt. By now everyone in the world uses SI in international communication. However, There are still a few people are not aware of this. They stick to other units (e.g. imperial units) in international communication, which made people from different countries/regions confused. These people only think about themselves, without considering others. Not only does these people bring inconvenience to others, but also what they are doing is equal to turning the clock back, which is useless. From my perspective, these people are just too lazy to accept SI. In fact, SI is not difficult at all. Just use it and promote it, and you can handle it very well. Here are some things you can do to promote SI:

• When engaging in trade, state that you prefer your product or service in the SI because it is the legally preferred system of measurement for trade, according to the Convention of Metre.
• Write to elected officials supporting metric legislation and opposing anti-metric legislation.
• Write to media supporting SI and explaining its benefits
• Write to manufacturers praising them when they use SI products and use SI properly
• Write to manufacturers educating them when they do not use SI appropriately
• When you see misuse of SI, write to the responsible organization
• Metricate your own life (tape measures, thermometers, thermostats, cooking, etc.)
• Discuss the benefits of using SI with others
• Write editorials promoting SI and send them to trade journals in your profession
• Promote SI in any volunteer activities you do
• Volunteer to help the SI organizations in some capacity
• Promote SI among your co-workers
• Buy metric products, even if they cost a bit more
• Volunteer to coach or tutor metric at local science fairs or high schools
• Describe SI units visually instead of converting to other units on request

These are some available ways to get metricized for everyone. After all, most of the people in the world can do this, so SI is used everywhere in the world. These words are only write for the minority. If you think you belongs to the minority, please follow the ways and use SI actively. In addition, everyone have the right to promote SI. That means most people are "forcing" the minority to get metricized, so you do not have any excuse for rejecting SI, and you can do nothing but accept to use SI. Some of the people do not use SI because they think it is hard. In fact they are completely wrong. SI is very simple. If you learn it hard, you will be able to handle it very quickly.

In short, SI is used all over the world. If you are still using other units, please learn and use SI instead. and help most of the people to promote it. Only by using united units (SI units) can we break the barrier of the international communication.

Origin of SI units - Tonne

The tonne  (SI symbol: t) is a non-SI metric unit of mass equal to 1000 kilograms; it is thus equivalent to one megagram (Mg). 1000 kilograms is equivalent to 0.984 tons. Although not part of the SI, the tonne is "accepted for use with" SI units and prefixes by the CIPM, along with several other units like the bar, litre and day.

In French and all English-speaking countries that are predominantly metric, tonne is the correct spelling in writing. It is usually pronounced the same as ton /tʌn/, but when it is important to clarify that the metric term is meant, rather than ton (imperial unit), the final "e" can also be pronounced /ˈtʌnɪ/. In Australia, it is also pronounced /tɒn/.

Before metrication in the UK the unit used for most purposes was the Imperial ton of 2,240 pounds avoirdupois , equivalent to 1,016 kg, differing by just 1.6% from the tonne. The UK Weights and Measures Act 1985 explicitly excluded from use for trade many units and terms, including the ton and the term "metric tonne". However, for many purposes the Imperial ton and the tonne are so similar that it is not important to distinguish them, even in writing, and the spelling "ton" is still often used where "tonne" is meant. For example, even the Guinness Book of World Records accepts metrication without marking this by changing the spelling.

Ton and tonne are both derived from a Germanic word in general use in the North Sea area since the Middle Ages (cf. Old English and Old Frisian tunne, Old High German and Medieval Latin tunna, German and French tonne) to designate a large cask, or tun. A full tun, standing about a metre high, could easily weigh a tonne. An English tun (an old wine cask volume measurement equivalent to 954 litres) of wine weighs roughly a tonne, 954 kg if full of water, a little less for wine.

The spelling tonne pre-dates the introduction of the SI in 1960; it has been used with this meaning in France since 1842, when there were no metric prefixes for multiples of 106 and above, and is now used as the standard spelling for the metric mass measurement in most English-speaking countries. In the United States, the unit was originally referred to using the French words millier or tonneau, but these terms are now obsolete. The imperial units comparable to the tonne are both spelled ton in English, though they differ in mass.

The SI symbol for the tonne is "t", adopted at the same time as the unit itself in 1879. It is a symbol, not an abbreviation, and should not be followed by a period. Informal and non-approved symbols or abbreviations include "T", "mT", "MT", "mt", and "Te" (particularly in the offshore and nuclear industries).[citation needed] Some of these are actually SI symbols for other units: "T" is the SI symbol for the tesla and "Mt" is the SI symbol for megatonne (equivalent to one teragram); if describing TNT equivalent units of energy, this is equivalent to 4.184 petajoules.

A metric ton unit (MTU) can mean 10 kg within metal (e.g. tungsten, manganese) trading. It traditionally referred to a tonne of ore containing 1% (i.e. 10 kg) of metal.

In the case of uranium, the acronym MTU is sometimes considered to be metric ton of uranium, meaning 1000 kg.

In the petroleum industry the tonne of oil equivalent (toe) is a unit of energy: the amount of energy released by burning one tonne of crude oil, approximately 42 GJ. There are several slightly different definitions.

A gigatonne of Carbon dioxide equivalent (GtCO2eq) is a unit used by the UN climate change panel, IPCC, to measure the effect of a technology or process on global warming.

Like the gram and the kilogram, the tonne gave rise to a (now obsolete) force unit of the same name, the tonne-force, equivalent to about 9.8 kilonewtons: a unit also often called simply "tonne" or "metric ton" without identifying it as a unit of force. In contrast to the tonne as a mass unit, the tonne-force or metric ton-force is not acceptable for use with SI, partly because it is not an exact multiple of the SI unit of force, the newton.

In this post we introduced tonne, and the difference between ton and tonne. Please use the correct words when talking these two units.

Origin of SI units - Litre

The litre  (SI symbols L or l) is a non-SI metric system unit of volume equal to 1 cubic decimetre (dm³), 1000 cubic centimetres (cm³) or  1/1000 cubic metre. A cubic decimetre (or litre) occupies a volume of 10×10×10 centimetres and is thus equal to one-thousandth of a cubic metre.

The original French metric system used the litre as a base unit. The word litre is derived from an older French unit, the litron, whose name came from Greek via Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI, although not an official SI unit—the SI unit of volume is the cubic metre (m³). The spelling used by the International Bureau of Weights and Measures is "litre", a spelling which is shared by almost all English-speaking countries.

One litre of liquid water has a mass of almost exactly one kilogram, due to the gram being defined in 1795 as one cubic centimetre of water at the temperature of melting ice. Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact by definition.

The first name of the litre was "cadil"; standards are shown at the Musée des Arts et Métiers in Paris. Then the litre was introduced in France in 1795 as one of the new 'republican units of measurement' and defined as one cubic decimetre. One litre of liquid water has a mass of almost exactly one kilogram, due to the gram being defined in 1795 as one cubic centimetre of water at the temperature of melting ice. The original decimetre length was 44.344 lignes, which was revised in 1798 to 44.3296 lignes. This made the original litre 1.000974 of today's dm³. It was against this litre that the kilogram was constructed.

In 1879, the CIPM adopted the definition of the litre, with the symbol l (lowercase letter L).

In 1901, at the 3rd CGPM conference, the litre was redefined as the space occupied by 1 kg of pure water at the temperature of its maximum density (3.98 °C, 277.13 K) under a pressure of 1 atm. This made the litre equal to about 1.000028 dm³ (earlier reference works usually put it at 1.000027 dm³).

In 1964, at the 12th CGPM conference, the original definition was reverted to, and thus the litre was once again defined in exact relation to the metre, as another name for the cubic decimetre, that is, exactly 1 dm³.

In 1979, at the 16th CGPM conference, the alternative symbol L (uppercase letter L) was adopted. It also expressed a preference that in the future only one of these two symbols should be retained, but in 1990 said it was still too early to do so.

Litres are most commonly used for items (such as fluids and solids that can be poured) which are measured by the capacity or size of their container, whereas cubic metres (and derived units) are most commonly used for items measured either by their dimensions or their displacements. The litre is often also used in some calculated measurements, such as density (kg/L), allowing an easy comparison with the density of water.

One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at about 277.13 K (3.98 °C). Similarly: 1 millilitre of water has a mass of about 1 g; 1,000 litres of water has a mass of about 1000 kg (1 tonne). This relationship holds because the gram was originally defined as the mass of 1 mL of water; however, this definition was abandoned in 1799 because the density of water changes with temperature and, very slightly, with pressure.

Now a litre is defined as a special name for a cubic decimetre or 10 centimetres × 10 centimetres × 10 centimetres, (1 L ≡ 1 dm³ ≡ 1000 cm³). Hence 1 L ≡ 0.001 m³ ≡ 1000 cm³, and 1 m³ (i.e. a cubic metre, which is the SI unit for volume) is exactly 1000 L.

The litre, though not an official SI unit, may be used with SI prefixes. The most commonly used derived unit is the millilitre, defined as one-thousandth of a litre, and also often referred to by the SI derived unit name 'cubic centimetre'. It is a commonly used measure, especially in medicine and cooking.

Originally, the only symbol for the litre was l (lowercase letter L), following the SI convention that only those unit symbols that abbreviate the name of a person start with a capital letter. In many English-speaking countries, however, the most common shape of a handwritten Arabic digit 1 is just a vertical stroke; that is, it lacks the upstroke added in many other cultures. Therefore, the digit '1' may easily be confused with the letter 'l'. Further, on some typewriters, particularly older ones, the unshifted L key had to be used to type the numeral 1. Even in some computer typefaces, the two characters are barely distinguishable. This caused some concern, especially in the medical community.

As a result, L (uppercase letter L) was adopted as an alternative symbol for litre in 1979. The United States National Institute of Standards and Technology now recommends the use of the uppercase letter L, a practice that is also widely followed in Canada and Australia. In these countries, the symbol L is also used with prefixes, as in mL and µL, instead of the traditional ml and µl used in Europe. In the UK and Ireland as well as the rest of Europe, lowercase l is used with prefixes, though whole litres are often written in full (so, '750 ml' on a wine bottle, but often '1 litre' on a juice carton). In 1990, the CIPM stated that it was still too early to choose a single symbol for the litre.

Prior to 1979, the symbol ℓ (script small l, U+2113), came into common use in some countries; for example, it was recommended by South African Bureau of Standards publication M33 and Canada in the 1970s. This symbol can still be encountered occasionally in some English-speaking countries, and its use is ubiquitous in Japan and South Korea. Fonts covering the CJK characters usually include not only the script small ℓ but also four precomposed characters: ㎕, ㎖, ㎗ and ㎘ (U+3395 to U+3398) for the microlitre, millilitre, decilitre and kilolitre. Such usage in printed works is in conflict with the recommendations published by the BIPM on the advice of the major international standards organisations (including ISO, NIST, NPL, IAU, IUPAC and IUPAP) who state in the SI Brochure that unit symbols should be 'printed in Roman (upright) type regardless of the type used in the surrounding text'.

In this post we introduced a metric unit accepted for using with SI - litre. In the next post we will talk about another metric unit accepted for using with SI - tonne.