Markus Kuhn wrote:
"John Gilmer" writes:
There is NOTHING magin about the metric system except for the fact
that units differ by powers of TEN.

Apart from the minor fact that almost everyone (19 out of 20 people
on this planet) uses it, you mean?

And of course the fact that it is a coherent system, without a need
to memorize any unit-specific conversion factors in physics formulas?

And of course the fact that a surprising number of useful everyday
quantities such as

- earth gravity (~10 m/s^2)
- water density (~1000 kg/m^3)
- length of equator (~40000 km)
- speed of light (~300000000 m/s)
- atmospheric pressure (~100 kPa)
- recommended serving temperature of American soft drinks (0 deg C)
- recommended brewing temperature of English breakfast tea (100 deg
C)

etc. happen to to be within about 1-2% of a round number, making
the metric system unbelievably convenient for quick estimates
with mental arithmetic.

Not to forget convenient approximations such as

- length of an adult's step (~1 m)
- width of an adult's hand (~0.1 m)
- width of the nail of the small finger (~0.01 m)
- an hour's drive by car (100 km)
- an hour's walk (10 km)

Can you name even a single country that adopted its customary
units from the US?

Can you name a single country that reached the spectacular levels of
power, productivity, and wealth as the US - which did it without the
metric system?

Why do you think did almost every country decide independently
to move to the metric system during the past 200 years?

Markus