How Does Radioactive Decay Work?
If an isotope (forms of chemical elements that differ in the number of neutrons in their atomic nuclei) is radioacitve, it will break down naturally into a lighter element called a decay product. This process occurs at a predictable rate and can be used to determine how old an object is. What is a Half-life? A half-life is the time required for half of an element’s atoms in a sample to change to the decay product. In each half-life only half of the remaining radioactive atoms decay, no matter how large the sample is. Look at the diagram below which represents the radioactive decay of uranium-238. The shaded area represents the decay product which is lead-206. The half-life of uranuim-238 is 4.5 billion years, since this object has gone through two half-lives it is 9 billion years old.
