How do scientists determine the ages of fossils, artifacts, and stones? When archeologists dig up fossils and artifacts they do not come with tag telling us the approximate time period they are from. There are multiple ways to do this, radio carbon dating is the most exact way to do this.
Carbon is a building block of life. All that was once living has carbon within it. Carbon has an isotope (or variation with a different amount of neutrons) number 14. That means it has 8 neutrons and 6 protons. The unstable carbon converts to nitrogen 14 through a process in which the extra neutron turns into a proton. Thus, they have 7 protons and 7 neutrons.
Carbon decays happens slowly over thousands of years. It has a half life of 5,500 years. That means that 5,500 years is the approximate time when half of the carbon has decayed into nitrogen. Carbon has an infinite number of half lives, each half of the half life before them. Using this system of half lives, scientists measure the amount of carbon and the amount of nitrogen in the fossil. From that data they are able to check how old the fossil is. For things like rocks without carbon in it, they look at the layer it was found in. Lower layers are older while layers higher up are newer. If they know the age of the fossil in the same layer as the rock they are able to determine the approximate age.
Source: http://phet.colorado.edu/
Carbon is a building block of life. All that was once living has carbon within it. Carbon has an isotope (or variation with a different amount of neutrons) number 14. That means it has 8 neutrons and 6 protons. The unstable carbon converts to nitrogen 14 through a process in which the extra neutron turns into a proton. Thus, they have 7 protons and 7 neutrons.
Source: http://phet.colorado.edu/
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