.split() Qeustion

Dave Angel davea at davea.name
Fri Aug 16 01:27:49 EDT 2013


Roy Smith wrote:

> In article <520da6d1$0$30000$c3e8da3$5496439d at news.astraweb.com>,
>  Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
>
>> On Thu, 15 Aug 2013 16:43:41 +0100, Chris Angelico wrote:
>> 
>> > A mole is as much a number (6e23) as the light year is a number
>> > (9.5e15).
>> 
>> Not quite. A mole (abbreviation: mol) is a name for a specific number, 
>> like couple (2) or dozen (12) or gross (144), only much bigger: 6.02e23. 
>> And I can't believe I still remember that value :-)
>
> I remember it as 6.022e23 :-)
>
> In my high school chemistry class, there was a wooden cube, about 1/2 
> meter on a side, sitting on the lecture desk in the front of the room.  
> The only writing on it was "6.022 x 10^23".  It sat there all year.
>
> The volume of the cube was that of 1 mole of an ideal gas at STP.
>
>> A light-year, on the other hand, is a dimensional quantity. Whereas mole 
>> is dimensionless, light-year has dimensions of Length, and therefore the 
>> value depends on the units you measure in:
>> 
>> 1 light-year:
>> 
>> = 3.724697e+17 inches
>> = 0.30660139 parsec
>> = 9.4607305e+12 kilometres
>
> Hold your hands out in front of you, palms facing towards each other, 
> one shoulder-width apart.  That distance is about one light-nanosecond.

Narrow shoulders.

I figure it just under a foot.  I once attended a lecture by Grace
Hopper where she handed out "nanoseconds," pieces of wire about a foot
long.  She said that the beaurocrats were always asking how much is a
nanosecond, and couldn't imagine what a billionth was like.  So she gave
them something physical.

-- 
Signature file not found




More information about the Python-list mailing list