Half-life is the time it takes for half of the unstable nuclei in a sample to decay.
Even though radioactive decay is a random process, we can predict when half the sample will
have decayed. This property makes half-life useful for dating archaeological samples and
medical applications.
In this simulation:
Green dots represent active radioactive particles
Red dots represent decayed particles
Watch how the number of remaining particles approaches half of the initial amount after one half-life
Note that it takes the same amount of time for the sample to decay from 100% to 50% as it does to decay from 50% to 25%
Key GCSE concepts demonstrated:
Radioactive decay is a random process at the individual particle level
Despite this randomness, the overall decay follows a predictable pattern
The half-life is consistent regardless of the current amount of material
The decay rate is proportional to the amount of material present
Decay never completely reaches zero, but continues to halve at each half-life interval