Changes

They are assumptions because they are unable to be proved one way or the other.

They are assumptions because they are unable to be proved one way or the other.

=== Ratios of materials ===

=== Initial quantities ===

Radiometric dating works on the assumption that there is some natural level of radioactive material and material that it will decay to in nature.  For example, with Radiocarbon dating, this is carbon 14 and Nitrogen 14.  The level of carbon 14 in the environment is stable with the two exceptions of [[bomb carbon]] and burning of ancient fuels (increasing the amount of carbon 12 in the environment).  Both of these can be removed by using wood from 1890 - prior to the widespread use of fossil fuels and well before the creation of the nuclear bomb.

One key assumption is that the initial quantity of the parent element can be determined.  With uranium-lead dating, for example, you must be able to determine how much uranium was in the sample to start with.  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).

With substances such as uranium, there is no creation of new uranium in the history of the world (with the exception of the very recent phenomenon of nuclear enrichment - which never gets back into ancient rocks so this is moot).

In the case of carbon dating, it is not the initial quantity that is important, but the initial ratio of C¹⁴ to C¹², but the same principle otherwise applies.

 

Young Earth Creationists assert that the rate of formation of carbon 14 changed with creation and the flood leading to incorrect results for dating. Moreover, there is no evidence the rate of decay of carbon 14 has been constant over long periods of time.

=== Rate of decay ===

=== Rate of decay ===