Another limitation is that carbon-14 can only tell you when something was last alive, not when it was used.
A limitation with all forms of radiometric dating is that they depend on the presence of certain elements in the substance to be dated.
Radiometric dating — through processes similar to those outlined in the example problem above — frequently reveals that rocks, fossils, etc.
We can measure directly, for example by using a radiation detector, and obtain a good estimate of by analyzing the chemical composition of the sample.
The half-life , specific to each nuclide, can be accurately measured on a pure sample, and is known to be independent of the chemical composition of the sample, temperature and pressure.
One way Young Earth Creationists and other denialists try to discredit radiometric dating is to cite examples radiometric dating techniques providing inaccurate results. Helens, creationists attempted discredit the discipline through dishonest practices.
This is frequently because the selected technique is used outside of its appropriate range, for example on very recent lavas. The Institute for Creation Research's RATE project aimed to show scientifically that methods of radiometric dating produced wildly inconsistent and incorrect values.
Carbon dating works on organic matter, all of which contains carbon.
However it is less useful for dating metal or other inorganic objects.
Symbolically, the process of radioactive decay can be expressed by the following differential equation, where N is the quantity of decaying nuclei and k is a positive number called the exponential decay constant.
The meaning of this equation is that the rate of change of the number of nuclei over time is proportional only to the number of nuclei.
Due to the long half-life of uranium it is not suitable for short time periods, such as most archaeological purposes, but it can date the oldest rocks on earth.