[time-nuts] One Kg Quartz Resonator

Magnus Danielson magnus at rubidium.dyndns.org
Wed Jan 23 03:34:37 EST 2013


On 01/23/2013 02:32 AM, Mike S wrote:
> On 1/22/2013 3:30 PM, Bruce Griffiths wrote:
>> But can the number and type of atoms in such a standard be counted?
>> Otherwise its not a primary standard.
>
> Can you have a Cs under zero acceleration and at zero temperature, the
> only conditions for which the second is defined? Since most metric units
> are derived from the definition of the second, are any "primary
> standards," in your opinion?

Isn't it defined for zero sea-level, that is standard acceleration?

Besides, as you put two standards in the same lab at the same level, 
they should give the same values. Some of the art is to compensate for 
various effects, so accurately model, estimate and compensate goes into 
the tricks of trade today.

The standard shifts as better methods of realizing them occurs, the kg 
has been taking a long time to shift from the original lump of metal.

Cheers,
Magnus


More information about the time-nuts mailing list