On Wed, 11 Jun 2003 01:16:08 +0900, Curt  ...
>
>
>
>Brett Robson wrote:
>
>> >
>> >The last I heard, the Avoirdupois pound was defined as being the weight of
>> >27.7015 cubic inches of distilled water at 62 degrees F with the barometer
>> >being at 30 inches.
>> 
>> 1. avoirdupois pound is not an imperial pound
>
>You're right here.  Congratulations.  Don't let it go to your head
>though....
>
>> 2. your definition is pound-force not pound
>
>A pound force is a pound.  

... when gravity equals exactly 1. Gravity is not constant in the universe or
even on the surface of the earth.



>
>> 3. your definition is /less/ accurate than using a standard object
>>    (perhaps this would be an interesting homework project for you. Discuss a
>> practical way of maintaining as constant the 3 variables, volume, temp, and
>> atmospheric
>>     pressure. Be sure to mention the effect of measurement on values)
>
>Umm, why couldn't you use any number of commercially available devices
>to maintain the desired temperature, volume, and pressure?

Firstly water is notoriously difficult to keep at a constant temp. Secondly
these 3 factors are all related to each other. Increase one and you have to
decrease the other two.


>
>>3. how can a measurement system define something without any outside references?
>
>I don't know.  You tell me.  If you could include why it is relevant to
>this discussion, that would be good too.

Sorry, I thought it was obvious. Kevin's definition uses 3 measurements which
are defined elsewhere. This is not as much a definition as a conversion between
units.


> 
>>if you don't understand any of the above please refer to an introductory physics
>> text.
>
>Could you let me know which introductory physics text you referenced
>before writing your post?
>

I didn't. As phyics is all about measurement of the physically world then if
your introductory physics book did not include an extensive section on units of
measurement then I suggest you get a new book.

---
"he [John Ashcroft] deliberately left Jesus out of office prayers to avoid
offending non-Christians."   - Ben Shapiro 27/2/2003