Carbon dating explained simply
is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past. To understand radiocarbon dating, you first have to understand the word Although an element’s number of protons cannot change, the number of neutrons can vary slightly in each atom.
But when gas exchange is stopped, be it in a particular part of the body like in deposits in bones and teeth, or when the entire organism dies, the ratio of carbon-14 to carbon-12 begins to decrease.
On the other hand, if tons of half-lives have passed, there is almost none of the sample carbon 14 left, and it is really hard to measure accurately how much is left.
Since physics can't predict exactly when a given atom will decay, we rely on statistical methods in dealing with radioactivity, and while this is an excellent method for a bazillion atoms, it fails when we don't have good sample sizes.
The unstable carbon-14 gradually decays to carbon-12 at a steady rate. Scientists measure the ratio of carbon isotopes to be able to estimate how far back in time a biological sample was active or alive.
This plot shows the level of carbon-14 in the atmosphere as measured in New Zealand (red) and Austria (green), representing the Southern and Northern Hemispheres, respectively.