Metrication Totally Explained

Everything about Metrication totally explained

Metrication (or metrification) refers to the introduction of the SI metric system as the international standard for physical measurements—a long-term series of independent and systematic conversions from the various separate local systems of weights and measures. Metrication began in France in the 1790s and spread widely during the following two centuries.
   Based on an old U.S. Metric Association survey it's commonly cited that only the United States of America, Liberia and Burma (Myanmar) have not officially adopted the metric system. But Guyana, for example, has officially adopted the metric system every 3-5 years, on average, since 1981, but each time with little success. Antigua, again 'officially' metric, is only slowly moving toward implementing the metric system.
   The United Kingdom and Saint Lucia are officially in the process of conversion, although the UK has been granted permanent exemptions by the EU for the mile and yard in road markings, and for the pint for beer and milk. In 2007, the European Commission also announced that it was to abandon the requirement for metric-only labelling on packaged goods, and to allow dual metric-imperial marking to continue indefinitely. Other countries in the former British Empire completed metrication during the second half of the 20th century, the most recent being the Republic of Ireland, which finalised conversion in early 2005 after beginning in the 1970s.
   The United States and the United Kingdom see active opposition to metrication today. While other countries, like France and Japan, also had significant popular opposition at one time for similar reasons, metrication is now accepted.

Before the metric system

In medieval Europe, local laws on weights and measures were set by trade guilds on a city-by-city basis. For example, the ell or elle was a unit of length commonly used in Europe, but its value varied from 40.2 centimetres in one part of Germany to 70 centimetres in The Netherlands to 94.5 centimetres in Edinburgh. A survey of Switzerland in 1838 revealed that the foot had 37 different regional variations, the ell had 68, there were 83 different measures for dry grain and 70 for fluids, and 63 different measures for "dead weights". When Isaac Newton wrote Philosophiae Naturalis Principia Mathematica in 1687, he quoted his measurements in Parisian feet so readers could understand the size. Examples of efforts to have local intercity or national standards for measurements, include the Scottish law of 1641, and the British standard Imperial unit system of 1845, which is still commonly used in the UK. At one time Imperial China had successfully standardised units for volume throughout its territory but by 1936 official investigations uncovered 53 dimensions for the chi varying from 200 millimetres to 1250 millimetres; 32 dimensions of the cheng, between 500 millilitres and 8 litres; and 36 different tsin ranging from 300 grams to 2500 grams. However, revolutionary France was to produce the definitive International System of Units which has come to be used by most of the world today.
The desire for a single international system of measurement derives from growing international trade and the need to apply common standards to goods. For a company to buy a product produced in another country, they need ensure that the product will arrive as described. The medieval ell was abandoned in part because its value couldn't be standardised. It can be argued that the primary advantage of the International System of Units is simply that it's international, and the pressure on countries to conform to it grew as it became increasingly an international standard. SI isn't the only example of international standardisation; several powerful international standardisation organisations exist for various industries, such as the International Organisation for Standardisation, the International Electrotechnical Commission, and the International Telecommunication Union.

Conversion process

There are three common routes that nations take in converting from traditional measurement systems to the metric system. The first is a quick, so called "Big-Bang" route which was used by Australia and India in the 1960s and several other developing nations since then. The second route is to phase-in units over time, and progressively outlaw traditional units. This method, favoured by industrial nations, is slower and generally less successful. The final route is to redefine traditional units in metric terms. This method has been used successfully where traditional units were ill-defined and had regional variations.
   The first route, "Big-Bang", is to simultaneously outlaw the use of pre-metric measurement, metricise, reissue all government publications and laws, and change education systems to metric. India's changeover lasted from 1 April 1960, when metric measurements became legal, to 1 April 1962, when all other systems were banned. The Indian model was extremely successful and was copied over much of the developing world.
   The second possibility, and first phase-in route, is to pass a law permitting the use of metric units in parallel with traditional ones, followed by education of metric units, then progressively banning the use of the older measures. This has generally been a slow route to metric. The British Empire permitted the use of metric measures in 1873, but the changeover wasn't completed in most countries until the 1970s and 1980s when governments took an active role in the now-independent parts of the empire. Japan, too, followed this route and didn't complete the changeover for 70 years. In the United Kingdom, the process is still incomplete. By law, loose goods sold with reference to units of quantity have to be weighed and sold using the metric system. Until September 11 2007 British law stated that non-metric labeling on packages would become illegal after December 2009, however the European Union has since granted the UK the right to use supplementary measures (imperial units alongside metric) indefinitely. (See metrication in UK for details.)
   A final possibility is to redefine traditional units in terms of metric values. These redefined "quasi-metric" units often stay in use long after metrication is said to have been completed. China followed this route, and thus while scientists in China know and use the kilogram, common people retain the jin (catty), which now has a value of 500 g. In the Netherlands, 500 g is informally referred to as a pond (pound) and 100 g as an ons (ounce), and in Germany and France 500 g is informally referred to respectively as ein Pfund and une livre . In Denmark, the re-defined pund (500 g) is occasionally used, particularly among older people and (older) fruit growers, since these were originally paid according to the number of pounds of fruit produced. In Sweden and Norway a mil (mile) is informally equal to 10 km, and this has continued to be the predominantly used unit in conversation when referring to geographical distances. In the 19th century Switzerland had a non-metric system completely based on metric terms, e. g. 1 Fuss (foot) equal to 0.30 m = 10 Zoll (inches) equal to 0.03 m = 10 Linien (lines) equal to 0.003 m.
   It is difficult to judge the degree to which ordinary people change to using metric in their daily lives. In countries that have recently changed, older segments of the population tend to still use an older and more familiar system. Also, local variations abound in what exactly becomes metricated and what does not. In Canada, for example, ovens and cooking temperatures are usually measured in degrees Fahrenheit, and Canadians almost invariably use Fahrenheit for cooking; though this isn't necessarily by choice but may instead be due to the overwhelming influence of the neighbouring and largely non-metricated United States. In the UK, which is still in the process of changing over completely, Fahrenheit is seldom encountered (except when some people talk about hot summer weather) while other metric units are often used in conjunction with older measurements, and road signs use miles rather than kilometres. Such countries could be said to be "semi-metric".

Exceptions

As of 2007, the metric system dominates all but three countries — Burma, Liberia, and the United States). Traditional measurements are still used in some areas, for example in plumbing the diameters of pipes are still measured in inches in some countries (in the UK all new pipes are metric). Automotive wheel diameters are still set as whole inch measurements (though tire widths are measured in millimetres) and dots per inch continues to be used in describing graphical resolution in the computer industry. Television and monitor screen diameters are still commonly cited in inches in many countries; however in Australia, centimetres are often used for CRT televisions, whilst CRT computer monitors and all LCD monitors are measured in inches. The only exception to the metrication process in Ireland was the pint in bars, pubs and clubs; though alcohol sold in any other location is in metric units (usually 333 ml (bottled beer), 500 ml (canned beer), 750 ml (wine) or 1 l (spirit)). In Australia, a pint of beer was redefined to 570 ml (see Australian beer glasses). In both metric and non-metric countries, racing bicycle frames are generally measured in centimetres, while mountain bicycle frames are measured in inches.
In some countries (like Antigua, see above), the transition is still in progress. The Caribbean island nation of Saint Lucia announced metrication programs in 2005 to be compatible with CARICOM. In the United Kingdom, the metric system is compulsory in most, but not all, industries. In the UK, the metric system had been legal for nearly a century before metrication efforts began in earnest. The government had been making preparations for the conversion of the Imperial unit since the 1862 Select Committee on Weights and Measures recommended the conversion and the Weights and Measures Act of 1864 and the Weights and Measures (Metric System) Act of 1896 legalised the metric system. In 1965, with lobbying from British industries and the prospects of joining the European Community, the government set a 10 year target for full conversion and created the Metrication Board in 1969. Metrication did occur in many areas during this time period, including the re-surveying of Ordnance Survey maps in 1970, decimalisation of the currency in 1971, and the teaching the metric system in schools. However, no date was set for making the use of the metric system compulsory and the Metrication Board was abolished in 1980 following a change in government. The 1989 European Units of Measurement Directive (89/617/EEC) required all member states to make the metric compulsory, however, the British negotiated certain derogations (delayed switchovers), including miles for road signs, and pints for draught beer, cider, and milk sales. Advocacy groups such as the Metric Martyrs, the British Weights and Measures Association, and the Active Resistance to Metrication continue to resist the compulsory use of the metric system, on the grounds that some surveys have shown that a lot of British people don't think in metric terms and because physical repackaging into rounded metric numbers could lead to reducing the quantity of goods sold for the same price. It should, however, be noted that some items have been rounded up during metric changeover, for example spirits were changed from of a gill (23.7 ml) to 25 ml and the standard loaf from 14 ounces (396.9 g) to 400 g.

Non-metric countries

Liberia, Burma (Myanmar), and the United States are the three countries that have yet to adopt metric as their official system of measurement. However, as discussed elsewhere on this page, in many other countries traditional systems are still widely used, even if not officially sanctioned. In the United States the use of the metric system was made legal as a system of measurement in 1866 and the United States was a founding member of the International Bureau of Weights and Measures in 1875. The system was officially adopted by the federal government in 1975 for use in the military and government agencies. In 1985, the metric system was made the preferred (but predominantly voluntary) system of weights and measures for United States trade and commerce (see Metrication in the United States). It has remained voluntary for federal and state road signage to use metric units, despite attempts in the 1990s to make it a requirement. A 1992 amendment to the Fair Packaging and Labeling Act (FPLA), which took effect in 1994, required labels on federally regulated "consumer commodities" to include both metric and U.S. customary units. An amendment that would allow (but not require) metric-only labels is currently under consideration, and all but two US states (New York and Alabama) have passed laws permitting metric-only labels for the products they regulate. Likewise, Canada also legally allows for dual labeling of goods provided that the metric unit is listed first and that there's a distinction of whether a liquid measure is a U.S. or a Canadian (Imperial) unit. Regardless, the American public and much of the private business and industry use U.S. customary units. At least two states, Kentucky and California, have even moved towards demetrication of highway construction projects.

Air and sea transport

Some industries have resisted metrication. Non-metric measures in air and sea transport retain worldwide dominance. In these areas the nautical mile is still widespread. This may be because various historical versions of the nautical mile were originally designed to represent a minute of arc of on the surface of the Earth at certain points (the definition in use today is standardised as 1852 metres exactly). While the metre was also based on the Earth with 100 km equal to an arc of 1 grad, those units of angle have not seen widespread use, though they do appear on some maps.
The prime unit of speed for maritime and air navigation remains the knot (nautical mile per hour). But before the 1960s, statute miles per hour (which bears no relationship to the Earth) was most often used for this purpose, and remained in fairly common use for some purposes in the 1970s and later.
The prime unit of measure for aviation (altitude) is usually estimated based on air pressure values and described in nominal feet rather than nominal metres. A vertical spacing of 1,000 feet has become the standard measure for safety and clarity for purposes of air traffic control. However, several countries and air forces (mostly former countries of the Warsaw Pact) use metres for altitude today. Thus, an individual pilot can sometimes operate with altitudes in metres and sometimes in feet. The policies of the International Civil Aviation Organization (ICAO) relating to measurement are:

there should be a single system of units throughout the world
the single system should be SI
the use of the foot for altitude is a permitted variation

Consistent with ICAO policy, aviation has undergone a lot of metrication over the years. For example, the United Kingdom and Ireland metricated runway length and many other measures several decades ago. The United States metricated temperature reports in 1996 and the US military has metricated some reports of visual range. Metrication is also gradually taking place in cargo weights/dimensions and fuel volume/weight.

Accidents and incidents

Confusion over units during the process of metrication can sometimes lead to accidents. One of the most famous examples is the Gimli Glider, a Boeing 767 that ran out of fuel in Canada in 1983 due, in large part, to confusion at Air Canada during Canada's metrication.
While not strictly an example of national metrication, the use of two different systems was a contributing factor in the loss of the Mars Climate Orbiter in 1998. NASA specified metric units in the contract. NASA and other organisations worked in metric units but one subcontractor, Lockheed Martin, provided thruster performance data to the team in pound force seconds instead of newton seconds. The spacecraft was intended to orbit Mars at about altitude but the incorrect data meant that it descended to about and probably burned up in the Martian atmosphere.

Opposition

Interestingly, considering it was the birthplace of the metric system, France experienced a particularly rough journey to metrication. The traditional French measuring system was chaotic, with size of units differing in each small town, and often even within towns. Lyon had two different values of pound in general use, one of 14 ounces, and another of 15 ounces, the latter only being used for measuring silk. The revolutionary government, which saw the newly conceived metric system (commissioned by the previous king) as a good fit for its ideology of "pure reason", first attempted a quick conversion, legalising metric units in 1795 and, just four years later, banning the use of traditional units. Massive popular opposition led Napoleon, after he came to power, to roll back these reforms. He publicly denounced the previous government for "tormenting people with trifles". It appears that it was decimalisation that disturbed the people most — as, although Napoleon decreed that there should be "such fractions and multiples as were generally used", he redefined the old base units in metric terms. The original metric system was made law again in France in 1837. )
Overall, few countries have experienced much popular opposition to metrication. Some, such as 19th century European countries, Russia, India and China, converted before most of their populations were literate, so the initial conversion affected few people. For others, such as Ireland, the previous system (ie. imperial) was seen as foreign.Further Information

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