What do people mean when they say “half life of element X”?
In: 0
A spoonful of material will have some [10^20 atoms](https://en.wikipedia.org/wiki/Avogadro_constant) in it.
And any single atom may react or decay or *do something* quite randomly, could be within the next second or it could be 2000 years from now. Processes at the atomic level are very very random, as far as when they happen exactly.
So the best way to specify how a material will behave (with all its 10^20 atoms) is to do a statistical average of how long it’ll take all those atoms to decay. Between 1 second and 2000 years, it’ll probably take about 50 years for a good chunk of those atoms to decay, with only a few ‘stubborn’ ones lasting the full 2000 years.
So you say that “the half life” = 50 years. It takes about 50 years for HALF the atoms in a spoonful of material to go boom.
This has the advantage of being independent of “size”. It would also take 50 years for half the atoms in the Earth or the Sun to go boom. The “half life” applies to the element, independently of the actual quantity of it.
Latest Answers