In the chapter on Fossils, we will discover that dating rocks by their fossils is based on circular reasoning:  Each strata is a certain age because of certain key fossils in it;  the fossils in the strata are a certain age because evolutionary theory says they should be that certain age, and also because they are in rock strata which is that same age.
Thus, fossil-strata dating methods are hopelessly foundered.
The half-life is the length of time required for half of any given amount of an element to decay into another element.
For example, if one begins with a gram of carbon-10, 20 seconds later only half a gram will remain, after 40 seconds only a quarter gram will be left, after 60 seconds an eighth of a gram, after 80 seconds one sixteenth of a gram, and after 100 seconds have elapsed from the beginning of the experiment, only one thirty-second of the original carbon-10 will remain (left).
This slow decay of carbon-14 is the basis of a widely used dating method for archaeological materials.
As long as any organism is alive, its carbon atoms are being exchanged continuously with the atmosphere.
It is assumed that the amount of radioactive carbon left in the sample indicates how old it is. It is based on several assumptions, one of which is false.