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We are just catching up. 
How long is a piece of string ??
- Thread starter MaxHeadRoom
- Start date
But the Golden Ratio is (1+√5)/2
The U.S. is technically metric right now -- ask any lawyer and they can point you to all the nice legal statutes that prove it.
U.S. metrification started in in 1975 and will be complete in ten years.
There is even a USMB (United States Metrification Board) to oversea the ten-year conversion process. Or there was, until it was disbanded seven years in.
I remember the road signs being aggressively changed to include both metric and U.S. customary units for speed and distance (sometimes on the same sign, sometimes on separate signs). Then it stopped replacing existing signs and only included metric on new signs. Then they stopped doing that. Then they started taking down existing signs that only had metric. Then they started replacing dual-unit signs with customary-unit-only signs. You still occasionally see a speed limit sign that has both, but that's about it.
So---Technically, but not officially ?
It's... complicated.
Several laws, particularly The Metric Conversion Act of 1975, designate the metric system as the "preferred" system of weights and measures for U.S. trade and commerce and directed federal agencies to convert to the metric system "to the extend feasible". It was amended several times over the years, sometimes backing off some and other times stepping into things. But the conversion has always been voluntary for the citizenry as a whole -- does a government have the right and authority to tell me that I can't sell you a gallon of milk or by a half-acre plot of land from you unless we translate everything into metric units? What they could do, and tried to do, was require activities conducting business with the federal government to do so in metric units. But, even there, they made sure to put in weasel words to create loopholes that people quickly figured out how to exploit wholesale. For instance, the 1988 amendments codified what was already happening when it added, "to require that each Federal agency, by a date certain and to the extent economically feasible by the end of the fiscal year 1992, use the metric system of measurement in its procurements, grants, and other business-related activities, except to the extent that such use is impractical or is likely to cause significant inefficiencies or loss of markets to United States firms, such as when foreign competitors are producing competing products in non- metric units."
This effort is actually what led to me being a Units Nazi, as it played a huge role in the fatal accident that resulted from the person I was working with (and who was the one killed) failing to track their units properly because they did all of their work without units at all and just tacked on the units they expected the answer to have at the end. They did all of their work in the English units they had used all along, but the Act had forced the military to only purchase new machine tools that were calibrated in metric, which include the machine shop's lathe. So when he calculated the diameter of the shear pin of a test rig he and I were designing, he had to convert from inches to centimeters. Unfortunately, as the accident investigation that scoured his notes later revealed, he had multiplied his work by 2.54 midway through to do the conversion, but the number he was multiplying it by was actually related to the area of the pin, not the diameter. Proper tracking of units would, of course, caught the mistake immediately. Had the machine shop been able to purchase a lathe that used the units everyone in the shop was familiar with, the whole incident might not have happened. Instead, a shear pin that had a design safety factor of 2 was actually something like 25% over it's shear strength at the normal load.
Anyway, as it often the case with laws that are passed with "dates certain" or with things that have to happen in the future, once the cameras stop clicking and the politician's step away from the microphones proclaiming their historic legislative achievement, the deadlines quietly pass and know was does anything beyond shaking their head if it's every mentioned again, because the legislation didn't include any provision for enforcement or spell out sanctions for non-compliance. When there was a dust-up about federal agencies failing to submit the required annual reports to Congress, Congress passed the The Federal Reports Elimination and Sunset Act of 1995 to officially repeal the requirement.
I live in a country where road distances are measured miles, and any other distances in metres, fuel is sold in litres, and fuel consumption quoted in miles per (imperial) gallon, or litres/100km. So signs warning of a height restriction say that there is a 3metre limit 400 yards away. Pubs sell beer in pints and wine in millilitres. Supermarkets sell milk in pints and orange juice in litres. Wood was sold in 2440mmx1220mm sheets (but it's now shrunk to 2400x1200mm when no-one was looking) . . but one thing we don't use is cups!
In many cases, changing measurement units is a huge up-front cost factor. For example, Coca Cola cans about 30 billion 12 oz aluminum cans each ear in the U.S.. That's a HUGE installed base in equipment to do everything associated handling that size can, from making the can itself, to filling it with product, to storing it in efficient warehouse sets ups, to the millions of vending machines that dispense them. That's a huge amount of inertia to overcome. But new product lines are a different matter. When the 2-liter format came along, there was no established half-gallon container, or anything similar, so new equipment and lines had to be set up whether it was English or metric, so they chose metric to be more compatible with establishing a global product.
But transitions like this are slow, incremental, and erratic. They will get you there eventually, but, not anytime soon (we've been metrifying for half a century and it's hard to really tell that we are much further along than when we started in 1975.
Part of the original thinking of the Metrification Board was that if the public schools only taught kids the metric system when they were young, then it would only take one generation to cement the transition culturally so that they would force industry to change due to consumer demand. I went to school during this time (I was in 4th grade in 1975 and remember well the sudden emphasis that was placed on metric education when I was in junior high). But, as so often happens, the politicians love to think that society will respond the way that they want them to respond instead of considering how they will actually respond. The metric education aspect of the curriculum was treated by almost everyone as a mandated-module that had to be given lip-service to. It was almost like, Okay, kids. On Tuesday we will have the annual sex-ed class and on Wednesday we will cover the metric system. Very little of the curriculum actually changed because all of the existing textbooks, and worksheets, and school supplies were in English units, as well as all of the teachers being already comfortable and prepared to teach things using English units like they had always done. So you might see one question on a homework assignment that used metric and you were told to either just slug through it, or convert it to English units, do the work, and then convert it to metric for the answer. There was virtually no effort to get people to actually use metric measures routinely so as to actually develop an instinctual feel for them. But even if the schools had done this, they would still have been leaving their six hours or so a day at school and spending most of their time doing real things in the real world, where the stuff they cooked at home was in fractions of a cup and pounds and ounces (fluid and dry), the football field was measured in yards, the distance to grandmas was in miles, and their family bought gas and milk in gallons. The experiences that they had that formed their innate sense of measure were predominantly in English units. So how the politicians could convince themselves that spending over $120M in "metric education kits" and mandating dual-system instruction (in 38 states by 1979) stood a chance against the everyday experiences of living and working in the real world were going to somehow make a difference. But, then again, we are talking about politicians.
But transitions like this are slow, incremental, and erratic. They will get you there eventually, but, not anytime soon (we've been metrifying for half a century and it's hard to really tell that we are much further along than when we started in 1975.
Part of the original thinking of the Metrification Board was that if the public schools only taught kids the metric system when they were young, then it would only take one generation to cement the transition culturally so that they would force industry to change due to consumer demand. I went to school during this time (I was in 4th grade in 1975 and remember well the sudden emphasis that was placed on metric education when I was in junior high). But, as so often happens, the politicians love to think that society will respond the way that they want them to respond instead of considering how they will actually respond. The metric education aspect of the curriculum was treated by almost everyone as a mandated-module that had to be given lip-service to. It was almost like, Okay, kids. On Tuesday we will have the annual sex-ed class and on Wednesday we will cover the metric system. Very little of the curriculum actually changed because all of the existing textbooks, and worksheets, and school supplies were in English units, as well as all of the teachers being already comfortable and prepared to teach things using English units like they had always done. So you might see one question on a homework assignment that used metric and you were told to either just slug through it, or convert it to English units, do the work, and then convert it to metric for the answer. There was virtually no effort to get people to actually use metric measures routinely so as to actually develop an instinctual feel for them. But even if the schools had done this, they would still have been leaving their six hours or so a day at school and spending most of their time doing real things in the real world, where the stuff they cooked at home was in fractions of a cup and pounds and ounces (fluid and dry), the football field was measured in yards, the distance to grandmas was in miles, and their family bought gas and milk in gallons. The experiences that they had that formed their innate sense of measure were predominantly in English units. So how the politicians could convince themselves that spending over $120M in "metric education kits" and mandating dual-system instruction (in 38 states by 1979) stood a chance against the everyday experiences of living and working in the real world were going to somehow make a difference. But, then again, we are talking about politicians.
When the change reached Mariners activity (British charts and all related publications) maybe around 1970, it was for good. Not only for the units but the drawing style and coloring.
Add to that, to the satisfaction of 2nd Mates in vessels, when they came on board, where already corrected (updated) to the most recent change as per the respective Notice to Mariners.
Those from USA, came not updated!! And where somewhat unnecessarily big in size. And costlier.
When going on board of old vessels destined to breaking the wise aware people tried to pick old Admiralty charts as collectibles (or even lamp shades).
I even used some of them as covers of frequently used books. Few of them still in my library.
Add to that, to the satisfaction of 2nd Mates in vessels, when they came on board, where already corrected (updated) to the most recent change as per the respective Notice to Mariners.
Those from USA, came not updated!! And where somewhat unnecessarily big in size. And costlier.
When going on board of old vessels destined to breaking the wise aware people tried to pick old Admiralty charts as collectibles (or even lamp shades).
I even used some of them as covers of frequently used books. Few of them still in my library.
Last edited:
musicalavtech
- Joined Mar 23, 2012
- 82
Then there is the mixed, standard use of multiple units of measure to describe tire sizes.
Then there was the episode that happened 90Km north of me, where the pilot had to turn a 747 into a Glider !
Happened in the change over for refueling from Imperial to Metric !
Happened in the change over for refueling from Imperial to Metric !
And tires are filled to a psi. Most gauges also show bar or kg/cm^2.
..... then there was that costly mix-up with units on the Hubble telescope.
That's a two-sided coin.As usual ... most of the trouble mentioned here are the consequences of people insisting on using anything but metric ...
Companies using the metric system account for only about 30% of global equity. They need to get with the program!
It was a Boeing 767, not a 747. It's a classic example more of the consequences of people not properly tracking units when they are doing computations. Multiple people got the wrong results, or were unable to validate other people's results, because they refused to pay attention to units. This happens whether working within a single set of measures or converting between them, though the latter adds additional risks.
More as usual, ALL of the trouble mentioned here are the consequence of people refusing to properly track their units. Plenty of other examples about, too.As usual ... most of the trouble mentioned here are the consequences of people insisting on using anything but metric ...
And kg/cm^2 is an improper pressure unit. The English system is far from unique in regard to people using mass and force interchangeably. In the English system, it's more prevalent because we use the same words (pounds and ounces) as unit names for both, relying on context to distinguish which concept it being used. But it still happens regularly with users of the metric system who use kg for both mass and force even though the system clearly distinguishes between the units for each (kilogram for mass, newton for force).
Only if you're strictly adhering to SI, in which it has been deprecated. A kgf (~9.8N) is still a widely used unit of force. It behooves any engineer to be familiar with it.
