Plants take in atmospheric carbon dioxide by photosynthesis, and are ingested by animals.
So, every living thing is constantly exchanging carbon-14 with its environment as long as it lives. The carbon in its body will remain until it decomposes or fossilizes.
Some chemical elements have more than one type of atom. Carbon has two stable, nonradioactive isotopes: carbon-12 (12C), and carbon-13 (13C).
In addition, there are trace amounts of the unstable isotope carbon-14 (14C) on Earth.
At high geomagnetic latitudes, the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide.
Carbon dioxide also permeates the oceans, dissolving in the water.
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So, scientists can estimate the age of the fossil by looking at the level of decay in its radioactive carbon.Scientists know how fast carbon-14 decays, so by measuring how much of it is remaining in a dead organism, they can figure out how long it has been dead.When scientists chipped the Iceman out of the block of ice he was found in, they tested his body to see how many carbon-14 atoms were remaining, which told them his age.Carbon dating is a way of telling the age of a once living thing by measuring the amount of carbon inside of it.
Carbon is an element that is found in every living thing on planet Earth.
Did you ever wonder how scientists know a fossil is 10,000 years old or a piece of paper is 2,000 years old? In this lesson you'll learn about carbon dating and how it works.