Kilogram's Future Hangs In The Balance

Re:Kilogram's Future Hangs In The Balance by aerique on Thursday August 20, 2009 @03:32AM (#774603)

In one sentence they say the kilogram's been taken out only three times and then later they suggest it might have gotten lighter because of periodic washings. Looking at the picture of how the kg is kept I assume the latter sentence is nonsense.

Can someone explain this to me?

[ Parent | on HN ]

Re:Kilogram's Future Hangs In The Balance by martey on Thursday August 20, 2009 @04:05AM (#774626)

From http://en.wikipedia.org/wiki/Kilogram :

Since the IPK and its replicas are stored in air (albeit under two or more nested bell jars), they gain mass through adsorption of atmospheric contamination onto their surfaces. Accordingly, they are cleaned in a process the BIPM developed between 1939 and 1946 known as “the BIPM cleaning method” that comprises lightly rubbing with a chamois soaked in equal parts ether and ethanol, steam cleaning with bi-distilled water, and allowing the prototypes to settle for 7–10 days before verification.

[ Parent | on HN ]

Re:Kilogram's Future Hangs In The Balance by eru on Thursday August 20, 2009 @04:07AM (#774628)

This may be a better article http://www.nytimes.com/2003/05/27/science/27KILO.html.

And http://www.bipm.org/en/scientific/mass/pictures_mass/cleanin...

[ Parent | on HN ]