| In industry, we have. At home, most households have little or no use for US dimension tools such as wrenches. You can service a bike with all metric tools. "Going metric" raises the question of whether we adopt metric measures for our existing standards (such as pipe threads) or actually adopt the ISO sizes. The latter would cause a brief but massive inventory management problem, that nobody's ever willing to put up with, even if there's a long term benefit. I believe we made a mistake in how we tried to teach the metric system. I learned in first grade: Metric is easy because it's just math. Most people heard "math" and freaked out. Metric was taught as a bunch of conversions and units. Inches were taught as: Here's a ruler, go measure some things. I remember talking to a machinist, and he said: "I hate the metric system because there's so much math." That was 30+ years ago. Today, machinists just read mm or inches from the same digital readout or CAD program. My Canadian friends learned metric as: Here's a ruler, go measure some things. |
The real advantage of metric is that you only have to do math once to calculate something. A cc is a ml is a gram. A liter is a cubic decimeter is a kg. It's just easy. A deep lake over a few square km? O(1) GT. Understanding orders of magnitude is a useful trait in a democracy.
You hit the nail on the head here though:
> My Canadian friends learned metric as: Here's a ruler, go measure some things.
Like any language, as long as you're translating you're loosing. Post signs in km and report temperature as C and everyone will understand it in less than a decade. A few years after I had a metric thermometer in my car C seemed easy.
It's not like the US failed to think of this. In the 80s they were posting signs in km. But back then there was a real economic cost to conversion for factories and machines. Now that's mostly gone, what remains is cultural resistance.