On 03/15/2007 05:03:47 PM, Anne Wilson wrote:
On Thursday 15 March 2007, Les Mikesell wrote: > Dotan Cohen wrote: > > All American measurements are of these unusual division. The inch > > itself is 1/12 foot, which is 1/5280 of a mile. Maybe not arbitrary, > > but not very intuitive. > > Not to defend the US units, but hasn't the meter been redefined at least > 3 times? Which of the choices was a unit that relates to something > intuitive to a human? >
None of the redefinitions of the meter relates to something intuitive to a human that I know of. The redefinitions were made to it easier to transmit/transfer/standardize the unit the world over. The length of a given number of cycles of a particular atomic transition's radiation is remarkably consistant, best anybody can tell. Not so for a irridium/<?something?> bar held in a vault somewhere. Same process happens with the second and hopefully soon (within the decade??) the kilogram. The second is defined by the time to make a certain number of cycles from some element's hyperfine splitting, not by a fraction of the rotation of the earth which wants to change by measurable amounts. We would like to get rid of the standard kilogram and replace it with a counted number of isotopically pure atoms, or a force, but that effort is still underway.
<<snip>>
My daughter and I make the men in the family wince because we tend to take measurements like 'four inches and two millimetres' :-) We're *very* accurate ;-)
Probably correct common usage, but that makes me itch. Precise maybe, but "accurate" doesn't seem right to me. Mixing units like that would make me wince also.
