Libby radiocarbon dating
The illustration below shows the three isotopes of carbon.Some isotopes of certain elements are unstable; they can spontaneously change into another kind of atom in a process called “radioactive decay.” Since this process presently happens at a known measured rate, scientists attempt to use it like a “clock” to tell how long ago a rock or fossil formed.Note that, contrary to a popular misconception, carbon dating is not used to date rocks at millions of years old.Before we get into the details of how radiometric dating methods are used, we need to review some preliminary concepts from chemistry.For example, all carbon atoms have 6 protons, all atoms of nitrogen have 7 protons, and all oxygen atoms have 8 protons.The number of neutrons in the nucleus can vary in any given type of atom.The earth has a magnetic field around it which helps protect us from harmful radiation from outer space. The stronger the field is around the earth, the fewer the number of cosmic rays that are able to reach the atmosphere.This would result in a smaller production of The cause for the long term variation of the C-14 level is not known.
This is a critical assumption in the dating process.It cannot be used directly to date rocks; however, it can potentially be used to put time constraints on some inorganic material such as diamonds (diamonds could contain carbon-14). Cosmic rays from outer space, which contain high levels of energy, bombard the earth’s upper atmosphere.These cosmic rays collide with atoms in the atmosphere and can cause them to come apart.So, a carbon atom might have six neutrons, or seven, or possibly eight—but it would always have six protons.
An “isotope” is any of several different forms of an element, each having different numbers of neutrons.
Protons and neutrons make up the center (nucleus) of the atom, and electrons form shells around the nucleus.