: To change to decimals is easy, basically you don't have to do anything except
: use the numbers differently (easier), however a full blown change to
: metric is MUCH harder.

: I read a real good article about this subject in a science magazine recently
: and it was based on the metric-english unit conversion mistakes that
: crashed the lander on mars (or maybe it was a TV show, I can't remember).

: Switching to metric is much harder than it appears.

: 1. It would take a few generations for the switch to be smooth. Teach the
: kids, phase in metric while the young ones use it, and then phase out the
: current system over time. It might be easy if you grew up with metric, but
: if you're used to the price of a gallon of gas, or how far a mile is
: etc..and suddenly they are selling gas in liters and using distances in
: kilometers it won't mean anything to you.

: 2. I work at a big airplane manufacturer. Now imagine that all of the
: fasteners are sized in fractions of an inch. All of them would have to be
: converted and wouldn't work out to normal metric fastener sizes. If the
: fasteners were to be switched to a metric size, there would have to be
: more or less of them in a given pattern to carry the same load. So
: basically all of the drawings would have to be changed over and many of
: them re-designed. Do you know how much money it costs to design an
: airplane? Somewhere in the Billions. Then there are the tools that would
: have to be changed to match the new designs etc... Oh, and what about the
: skin thicknesses that are in thousanths of an inch, they would have to be
: converted to new standard sheet thicknesses.
: Sure, the auto companies switched, but they are building completely new
: models every decade or so. The 737 and 747's are still being built today
: and although there have been a lot of upgrades, much of the structure is
: still the same since the 1960's. It would be a major change.

: If a new airplane were designed under the metric system, and the old ones
: were using the english units, imaging the many possibilities of mistakes
: in the Engineering departments that work on more than one airplane.

: 3. Then there's the airplane pilots that insist that altitude be measured in
: 100 foot increments. If they convert to meters a 100 meter increment is
: only about 1/3 as fine as a 100 foot increment. I see a hard landing
: coming. Are they going to start measuring in 30 meter increments (do the
: math on that every time you want to do a calculation)

: 4. One degree F change is about the fineness that a human can feel the
: difference in temperature. There are 180 degrees F difference between the
: freezing point of water and the boiling point. There is only 100 degrees
: difference in C.

: Metric is not necessarily better in all applications, just easier because
: everything is in based on 10.

: Now I am wondering why their isn't metric time (10 metric hours [deciday] to
: the day, 100 centidays to the day, and 1000 millidays to the day...etc).
: Would you still want to work 8 hours a day. Can you see how hard it would
: be for you to convert in your mind knowing how long an hour, minute,
: second is.

Funny, I grew up with metric and had to learn British system at age 16. Took me awhile. Now I'm use to British, I have to think to convert back to metric; but really, I can use both. Personally, I think metric makes a lot of sense. That may be why even the British are converted. USA is the only world power as the lone hold out on this issue.