Measurements

[Amy Z]

Haggridd wrote:

> The meter, in contradisinction, is some 
> fraction 
> > of the distance from the north pole to the equator on a line 
> passing 
> > through Paris.  BLECCH!!

Jenny wrote:

>Oh 
> yes, meter is the distance light travels in one second, because it 
> doesn't always go excatly the same distance

It's actually =derived= from the distance light travels in a second; 
light moves a LOT faster than 1 m/s (so does sound, or a thrown 
baseball, for that matter).

My Science Desk Reference says:

"The first [SI metric system] measurement, the meter, was based on the 
circumference of the Earth measured on a line through Paris and the 
north and south poles.  The line was divided by 40,000,000, and each 
division was called a meter . . . . Later, the meter was further 
defined as the length equal to 1,650,763.73 tiemsthe wavelength of 
orange light emitted when a gas consisting of a pure isotope of 
krypton (mass number 86) is excited in an electrical discharge.  In 
1983, the waavelength definition was replaced the the distance light 
travels in a vacuum in 1/299,792,458 second".

Paris may be arbitrary, but at least it was a good choice.  I mean, 
they could have made it Newark.

Amy Z
also related to Hermione