Jason Darfus wrote: Give them a micron and they'll take a meter. Just one problem with that. Micron is not an SI unit. The SI unit that replaces micron is micrometer (or, if you prefer, micrometre).
The problem with micron was that its symbol was � (Greek mu), which is a prefix, not a symbol, in SI. As the base SI unit of length is the meter (m), one millionth of a meter must be expressed as �m. For the same reason, other metric (but non-SI) units of length (e.g., �ngstr�m -- pronounced ongstrum) are no longer considered acceptable. Incidentally, in expressions such as "Give them an inch and they'll take a mile," the listener has to be able to visualize both of them in order to understand and appreciate the metaphor. I'm not sure how one would "give them" a distance as tiny as a micrometer. I'll leave it to those opposed to SI to try to translate metaphors, similes and other idiomatic constructs. For myself, I'll accept that the old ones will eventually die a natural death and new ones will evolve fairly naturally, without unnecessary contrivance. Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator]
