[time-nuts] Updating the unit of,time: the second.

[jimlux]

On 5/28/19 2:12 AM, Attila Kinali wrote:
> On Tue, 28 May 2019 03:06:12 +0100


> 
> Another way to look at it is, before you reach the point where the
> redefinition of the kg change becomes visible, other errors like
> buoyancy of air will introduce errors that are orders of magnitude
> largers (uncorrected the buoyancy induced uncertainty is IIRC in the
> a few ppm range, corrected its induced uncertainty goes to 1e-8).
> So, unless you are doing your weight measurements in vacuum, there is
> no need to care about the change of definition of kg.


Air is about 1mg/cc, so your measured mass is off by 1000 ppm if you're 
measuring water (depending on how much air your vessel displaces).  If 
you're weighing lumps of lead (11.3 g/cc), then only 100ppm error.