Half-Life... Radioactivity Decreases Exponentially with Time
 
 

• rate of decay measured by how long it takes for half to decay
• utterly random when a particular atom will decay
• half-life valid only for large number of nuclei

Why will an atom, just sitting there,
       decay according to some set probability?

Many physicists very unhappy that chance
       rules physical properties

Einstein proclaimed, "God doesn't play dice!"
       Einstein was wrong ...measure half-life of radioactive Indium