Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay.
Radioactive decay occurs at a constant rate, specific to each radioactive isotope.
Mathematically, the half-life can be represented by an exponential function, a concept with which entry-level students may not have much experience and therefore may have little intuition about it.
Any dead material incorporated with sedimentary deposits is a possible candidate for carbon-14 dating.Radiometric dating has been used to determine the ages of the Earth, Moon, meteorites, ages of fossils, including early man, timing of glaciations, ages of mineral deposits, recurrence rates of earthquakes and volcanic eruptions, the history of reversals of Earth's magnetic field, and many of other geological events and processes.Radioactivity and radioactive decay are spontaneous processes.Students often struggle with this concept; therefore, it should be stressed that it is impossible to know exactly when each of the radioactive elements in a rock will decay.Statistical probablity is the only thing we can know exactly.There are a number of ways that this can happen and when it does, the atom is forever changed.There is no going back – the process is irreversible. When we pour our popcorn kernels into a popcorn popper, the is no way to know which will pop first." Another way of explaining it is that when geologists talk about isotopes, they are talking about one element of differing masses.Isotopes of an element are atoms that all have the same atomic number (or number of protons in the nucleus) but have different atomic masses (hence different numbers of neutrons in the nucleus).Often students get bogged down in the fact that they don't "understand" how and why radioactive elements decay and miss the whole point of this exercise.If they can begin to comprehend that it is random and spontaneous, they end up feeling less nervous about the whole thing.