[USMA:23740] Re: Dallasnews - kilogram

[John Nichols]

I thought someone found that c is not constant recently but is slowing up
like me.

Just a thought.

I liked the Santa site.

I asked him for two head ache tablets to take away the pain of no sleep on Monday night helping students erect a memorial to a dead Professor. A tensgrity structure.

But they only worked in Imperial so it was also hard to translate constantly especially at 2 am. Donuts and coke for breakfast was a change from the Raisin Bran.

The structure reminded me of Parliament House in Canberra where the builders used 140,000 kg of steel to erect a mast weighing 1/7th the mass. At least these students at A&M only used a crane of equal mass to hold up the 12.4968m structure (41 feet in FFU).

Then in my Institution of Engineers Journal I saw a High School student build a bridge that weighed 435 g that held 70 some kilograms. It was neat.

Now to work. My head hurts.

John Nichols


At 07:16 AM 03-12-2002, you wrote:

John David Galt wrote:
>defining the kilogram to equal exactly the mass of 1000 cc of
>water at 4 deg C.

At what pressure?
Why 4 �C instead of the triple point?

The triple point is used in the definitions of kelvin (= 273.16 K) and
Celsius (= 0.01 �C). To be even more picky, I would expect an SI
definition to use kelvin rather than Celsius and m3 (although cm3 might
be acceptable) rather than 'cc'.

I would have thought that it would be better to define mass in terms of
a fixed number atoms (this is effectively what volume at the triple
point defines). However, these are all experimental definitions until
you get to a fundamental definition of mass based on something like E =
mc2

I presume that a better definition of mass is the sort of thing that
entertains a lot of physicists.

John Nichols BE, Ph.D. (Newcastle), MIE (Aust), Chartered Professional Engineer
Assistant Professor
Texas A&M University
Department of Construction Science
Langford AC
Rm: A414 MD 3137
College Station, TX 77843-3137

Electronic mail: [EMAIL PROTECTED]
Telephone: 979 845 6541
Facsimile: 979 862 1572
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