The year was 1964. I was a student in Mrs. Seiler’s elementary-school class in a school in rural Iowa. Mrs. Seiler introduced a new topic that we students would be learning about for the next few weeks — the metric system!
What we learned during those few weeks was that although the US was a bit behind most of the other countries of the world that had already adopted the metric system, it was by now settled that the US would now get up to date and would be in harmony with the rest of the world. We would be switching to the metric system.
We learned that a liter was around the same size as a quart.
We learned that a meter was roughly the same length as a yard.
We did exercises where we would add up, say, three measurements to arrive at a total, followed by calculating where the midpoint would be of the resulting length. We would do it once using our familiar units like sixteenths of an inch and inches and feet. And again using millimeters and centimeters and meters. We would work out how long it took to do the adding-up and the dividing-by-two in the two systems.
Even now, more than fifty years later, I find myself having to spend quite some time working out the midpoint of a length if the entire length is so many inches and so many eighths of an inch. And then having to double-check it.
Oh, and in this class in third grade, we memorized conversion constants. An inch is 2.54 centimeters. A meter is 39.37 inches. Even now, more than fifty years later, I do find myself using such conversion constants in daily life, I regret to realize.
And we learned that “a kilogram is 2.2 pounds”. But then maybe eleven years later, in first-year physics in college, there was the sort of abrupt realization that this is almost never true, except in a few very special cases for example where you happen to be on the surface of the earth. One of those units is measuring mass and the other of those units is measuring weight, and mass and weight are not the same thing. (This distinction had not been explored in detail in our third-grade elementary school class.)
Alas, the US lost its resolve from 1964 and did not ever actually convert to the metric system (except in science classes).
This discussion does remind me that when I first became a car owner, which was in high school in about 1973, the only car that I could afford to buy was a used Volkswagen. It was of course all metric. I had to buy a set of metric sockets for my socket wrench set and I had to buy metric combination wrenches. Where I lived, in those days, almost nobody had a car with metric fittings. At that time, and for some years thereafter, there was only one auto mechanic anywhere nearby who worked on metric cars! Looking back on it, I realize that this auto mechanic must have been looked at by many other mechanics in town as being subversive or crypto-Communist or something, with his shop filled with metric tools, and with his vaguely un-American customers whose cars did not use normal red-blooded American inch-type sockets and wrenches.
Maybe the most embarrassing example of this failure by the US came in September of 1999, when the Mars Climate Orbiter burned and broke into pieces after almost ten months of travel to Mars. The explanation, it turned out, was that there were two teams of engineers that had needed to cooperate to get some maneuver to work correctly. One team was in Europe and used metric units. The other team was in the US and, you know where this is going, was using inches and pounds. And the Americans, you know where this is going, failed to pay attention to the problem of metric and non-metric units being involved.
Saying this differently, if only the US had maintained its resolve in 1964 and carried out the conversion to the metric system, the Mars Climate Orbiter would not have burned and broken into pieces in 1999. It would have orbited Mars and returned valuable climate data.
Odd how the conversion never worked out. To this day, I can’t think and have intuition in metric units of length, force, whatever, when I am doing any sort of hands-on home and auto work. I also have a small vintage British car (non-metric fasteners), but with a US V6 crammed into it. Funny thing is, that GM crate motor bought in 2000 is metric wrt fasteners. So I always end up with a mix of US and metric tools scattered around the floor and under the hood. Cleanup always requires careful sorting back into the metric and US toolboxes. Maybe I should rattle can spray the metric tools neon orange.
Although the Mars Climate Orbiter disaster was not only down to the the different units issue, being a European mechanical engineer and then patent attorney who at one time worked for a US packaging company, using US units for very thin materials holding pressurised liquids – I feel your pain! Whenever we had to file European patent applications using a US priority application, the most boring and time-consuming part of the job was converting all the US units into the SI units required by the EPO. At work the discussions all centred around thous of an inch and PSI, but when writing patent applications we had to convert into fractions of mm and kPa (remembering to consider the number of significant decimal places).
I am from the UK and old enough to vaguely remember using Imperial units as a child and then converting to metric units as I grew older … now being horrified at the prospect of older people pushing hard to return to the “grand old days of imperial measures”! Fortunately, the scientific and European patent community to which I now belong will continue to use SI units and hopefully this will also remain the case for the populace at large, many of whom are too young to remember imperial measures.
And don’t forget: if you purchase a metric socket wrench set in the US, the sockets and the ratcheting handles are almost certainly going to connect to one another using 1/4″, 3/8″ and/or 1/2″ square posts.
It’s too bad that the US constitution does not permit the federal government to regulate things related to interstate commerce. If it did, the federal government might be able to specify what units must be used to specify the size of things sold in interstate commerce (with, of course, the freedom to also provide measurements in other units) or perhaps impose a tax on all nuts and bolts that are not a “normal” metric size.
But, if a government were powerful enough to interfere with commerce enough to “force” a change to metric, then it might also be powerful enough to (i) insist that manufacturers of food items list ingredients and nutritional content, (ii) insist that manufacturers and sellers of many items warn purchasers of safety issues (can you say “MSDS”?), (iii) prohibit fraudulent claims in interstate advertising or (iv) impose quality requirements on water that is collected, transported and consumed entirely within a single state.
Let’s never complain about the federal government’s failure to “force” a move to metric — they have the will to do it, but the Constitution does not grant the federal government the power to make it happen. As evidence that our representatives care deeply about metric, remember the many bills proposed in congress each term and the multiple attempts during the last 50 years to amend the constitution to permit a “forced march” to metric.
I’m reminded of the time in 1975, maybe 1976 when we turned on the TV and to a public service type announcement: a very serious gentle at a desk saying he was from the National Bureau of Standards. He said that since the US was going metric, the NBS felt obliged to explain the effect on the alphabet. Continuing, utterly deadpan he said:
A, B, C and D will remain the same. E, F and G will become a single letter as will G, H, I and J. “Elemeno” will be a single letter, as many people already think, they are!
He went on to explain the remaining three letters (PQR, STUV, and WXYZ as I recall. It was our maiden viewing of Chevy Chase and Saturday Night Live in a brilliant sketch.
Metric system is certainly better for science and technology, but for everyday life, the imperial system has built-in ergonomics. It was developed to match the scales of human experience and activity.
If the United States changed from pounds to kilograms, it would create mass confusion.
And actually the metric system is obsolete. What is us is SI. This was clear to me as I sat in the NIST library with the US meter bar 10 feet (3.05 meters) away from me behind single strength glass secured with a $3 lock.