How radioactive dating works
Over time, radioactive isotopes change into stable isotopes by a process known as radioactive decay.Some radioactive parent isotopes decay almost instantaneously into their stable daughter isotopes; others take billions of years.The rates of decay of various radioactive isotopes have been accurately measured in the laboratory and have been shown to be constant, even in extreme temperatures and pressures.
The discovery gave scientists a tool for dating rocks that contain radioactive elements.
Many elements have naturally occurring isotopes, varieties of the element that have different numbers of neutrons in the nucleus.
After one half-life, 50 percent of the original parents remains; after two, only 25 percent remains, and so on.
Decay curve of a radioactive element with a half-life equal to one time unit.
Note that at time 0, the time of the mineral's formation, the crystal contains only parent atoms.
At time 1, 50% of the parent atoms remain; at time 2, only 25% remain, and so on.