Since all living things contain carbon, carbon-14 is a common radioisotope used primarily to date items that were once living.
Carbon-14 has a half-life of approximately 5,730 years and produces the decay product nitrogen-14.
Each element is made up of atoms, and within each atom is a central particle called a nucleus.
Radioactive dating enables geologists to record the history of the earth and its events, such as the dinosaur era, within what they call the geologic time scale.
Radioactive dating uses the ratios of isotopes and their specific decay products to determine the ages of rocks, fossils, and other substances.
This means that after approximately 4.5 billion years, half of an original sample containing this isotope will decay into its decay product, forming the new isotope, Pb 206 (lead 206).
If another 4.5 billion years were to pass, then half of the remaining half of uranium-238 would also decay, leaving 25% uranium to 75% lead.
Absolute age is just a fancy way of saying definitive or specific age as opposed to the relative age, which only refers to how old or young a substance is in comparison to something else.
To illustrate, let's use the isotope uranium-238, which has a half-life of 4.5 billion years.
These neutrons can become unstable, and when they do, they release energy and undergo decay. Radioactivity occurs when the nucleus contains an excess amount of neutrons.
When an atom varies in the number of neutrons, the variation is called an isotope. During radioactivity, the unstable isotope breaks down and changes into a different substance.
Elements occur naturally in the earth, and they can tell us a lot about its past.