I'm sure it would take much longer than just two decades. At least three, probably four.



Seriously, 40 YEARS to learn how to multiply and divide by 10 and figure out where to put the decimals?
I started learning metric in 1972, in Grade 5. My junior high science classes used metric exclusively. By the time I was taking my high school chemistry courses, I was completely comfortable using metric measurements in most situations. Nowadays I may prefer to use miles instead of kilometres and inches instead of centimetres, but have no problem converting back and forth when convenient. It really is easier to measure some things in metric than imperial. I will admit that I can't visualize a hectare, but neither can I visualize 16 oz. of some liquid. As for temperatures, thank goodness for Celsius, as the other scale never did make any sense to me.I'm sure it would take much longer than just two decades. At least three, probably four.
Maybe, maybe not.
The US is what one of only 3 countries in the world not to use the metric system? Surely that is not beneficial to the US is the global economy? Sure older people might have more trouble adjusting to SI units but the younger generation(s) are simply brought up with it and it becomes the norm. People using different systems can cause confusion i.e. didn't NASA lose a probe because a contractor used Imperial instead of SI units. Even discussions on the Internet can cause confusion i.e ask someone what the temapture today was and they might say 40 now is that hot or cold, it depends if you are using C or F doesn't it? To something like 95% of the worlds population they would say that's hot, to something 5% they would say it's cold. Of course it's a non issue when they write 40F but more often or not the scale is never given.