posted by Supaman .
The international standard Kilogram in Paris is stored under double bell jars. What is the prupose of the jars?
Is it because the jars create a vacuum to prevent the standard from gaining mass due to oxidation? If so, why double jars? Are there any other reasons?
An interesting question. I would imagine that the bell jars serve several purposes, for example a) reducing the airborne contaminations that the standard picks up and b) ensuring that the mass is at the same temperature as the room. I believe the mass is stored in atmospheric air.
I know that the standard is periodically cleaned and there is a complicated protocol to do this.
You could try googling for the standard kilogram and see what you can find.
I hope this helps.