# The age of artefacts radioactive dating

There are two techniques for **dating** in archaeological sites: relative and absolute **dating**.Relative *dating* stems from the idea that something is younger or older relative to something else.Plankton absorbs, Carbon-14 from the ocean much like terrestrial plants absorb Carbon-14 from the air.

Looking at the graph, 100% of radiocarbon in a sample will be reduced to 50% after 5730 years.

In 11,460 years, half of the 50% will remain, or 25%, and so on.

How It Works: Carbon has 3 isotopic forms: Carbon-12, Carbon-13, and Carbon-14.

The numbers refer to the atomic weight, so Carbon-12 has 6 protons and 6 neutrons, Carbon-13 has 6 protons and 7 neutrons, and Carbon-14 has 6 protons and 8 neutrons.

The extra neutrons in Carbon-14’s case make it *radioactive* (thus the term, radiocarbon).

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