When I was growing up in a small citrus town in Southern California, we heard nothing about the metric system, and hardly anyone I knew had ever been across an ocean. And since we obviously were the supreme industrial power in the world, as had been demonstrated by World War II, there was certainly no thought of changing our good old system of inches, feet, pounds, and British Thermal Units (B.T.U.s). Certainly the metric system was out there, and there was some pressure to adopt it in the U.S., as can be seen in the chronology here.
It wasn’t until I took chemistry and physics in high school that I was introduced to the metric system, and then only fleetingly. At Caltech, we finally began using it, although only in science courses. Engineering courses held on to what was then called the “English” system. There was some discussion about this, since the metric system is more logical, more elegant, and easier to use. In fact, if you think about it, the English system is very weird.
When I started working as an engineer and began traveling abroad, I realized that we were in the minority—most of the world seemed to be metric. And still later, the U.S., or at least those involved in world trade, began to be aware of the cost of using a measuring system that was at odds with so many other people. I remember that my 1956 Austin Healey, a British car, used Whitworth, metric, and SAE (U.S.) nuts and bolts. A major inconvenience, which probably did not help sales in the U.S. Image what people in Europe thought of a car that used only S.A.E. threads.
But as more and more nations mandated the metric system (including England), we became more aware of the cost of not complying. In a sense we were manufacturing products that did not “fit” much of the rest of the world. In the 1960’s I was doing some consulting for the Department of Commerce, which was then actively pushing the metric system in the U.S. If you look at the Chronology again, you will see that a lot was going on at this time. One of my friends coordinated the 3 year U.S. Metric Study, which produced a 13 volume report measuring the cost of being non-metric, and recommending the U.S. should “go metric” through a national ten year program. It was accepted by Congress.
As can be seen in the Chronology, there has been progress since the 1960’s, especially in government agencies and in industries and other businesses that operate globally. But by the time my children went through school, the English system still was predominantly used in schools, but with quite a bit more attention paid to the metric system. And U.S. citizens were traveling more and becoming aware that we were in the minority. I remember metric speed limit signs appearing in Arizona and other areas close to metric Mexico. But metric speed limits are more commonly shown in a secondary role, as in the photograph above, and we tend to ignore them. There has been a greater push in industry to change from merely converting English dimensions to metric (one inch to 2.54 centimeters), to using more tractable metric dimensions (2.50 centimeters). But undoubtedly, many kids are still growing up in families who rely on the old English system, and learning the metric system as a somewhat unfamiliar second language
I ate breakfast today with the family of one of my sons, and my grandkids are being introduced to the metric system in the fourth grade, and my son works at Tesla Motors, which is pretty much all metric. So we are getting there. But It has taken us well over 100 years, and now we have the honor of being one of only three countries in the world who have not mandated the metric system—the other two are Liberia and Myanmar (and they are using it, although they have not mandated it). Perhaps we are indeed believers in U.S. exceptionalism (or maybe just slow) when it comes to weights and measures.