Redefining Avogadro's Number. A mole is the number of molecules in a gram of water: ~6.022 x 10
23. Unfortunately "a gram" is defined by
a chunk of metal in
a vault in France, the last of the seven SI units still defined by a physical artifact. Since the reference mass (known as "Le Gran K") is actually
changing over time (due to cleaning, handling, etc), the definition of a gram is currently temporally unstable.
Now a new proposal has been put forward to explicitly define the number to be a known integer: 602,214,141,070,409,084,099,072, which would fundamentally change the way we define a gram. Le Gran K could become a historical curiosity like
the original platinum meter stick.
posted by dkg
on Mar 2, 2007 -
39 comments
FBI Probes Pentagon Spy Case - Interesting how bad news about the Bush Administration seems to always come out on Fridays - "the FBI has a full-fledged espionage investigation under way and is about to -- in FBI terminology -- "roll up" someone agents believe has been spying not for an enemy, but for Israel from within the office of the Secretary of Defense at the Pentagon."
posted by jackspace
on Aug 27, 2004 -
37 comments
6.02x10^23. Anybody who has taken chemistry may remember that number as Avogadro's Number, the number of molecules of any gas present in a volume of 22.41 L and is the same for every element. Fun stuff, eh? Read more about one of the basics of chemistry at Chemistry.co.nz's
Avogadro's Law page. For more mole fun, including jokes, try the
National Mole Day Foundation. Why does Avogadro like blue cheese?
Because it's mole-dy.
posted by tdecius
on Sep 20, 1999 -
0 comments
