However, the nucleus has a strong positive charge and the electron shells have a strong negative charge.Any incoming negative charge would be deflected by the electron shell and any positive charge that penetrated the electron shells would be deflected by the positive charge of the nucleus itself.This interpretation unfortunately fails to consider observed energetic interactions, including that of the strong force, which is stronger the electromagnetic force.It is important that the sample not have had any outside influences.For these reasons, if a rock strata contains zircon, running a uranium-lead test on a zircon sample will produce a radiometric dating result that is less dependent on the initial quantity problem.Another assumption is that the rate of decay is constant over long periods of time, which is particularly implausible as energy levels changed enormously over time.Most are determined experimentally by institutions such as CERN with the Large Hadron Collider.Decays are very random, but for different elements are observed to conform to statistically averaged different lifetimes.

One assumption that can be made is that all the lead in the sample was once uranium, but if there was lead there to start with, this assumption is not valid, and any date based on that assumption will be incorrect (too old). Radiometric dating is a method of determining the age of an artifact by assuming that on average decay rates have been constant (see below for the flaws in that assumption) and measuring the amount of radioactive decay that has occurred.Radiometric dating is mostly used to determine the age of rocks, though a particular form of radiometric dating—called Radiocarbon dating—can date wood, cloth, skeletons, and other organic material.For example, a neutron-deficient nucleus may decay weakly by converting a proton in a neutron (to conserve its positive electric charge, it ejects a positron, as well as a neutrino to conserve the quantum lepton number); thus the hypothetical atom loses a proton and increments down the table by one element.