Radioactive carbon dating animation

04 Apr

In this interactive, learn how radiocarbon dating works, what it takes to determine a date in the lab, and why it's challenging to pinpoint a date precisely.We’re going to see what 'half-life' means and why radioactivity changes with time. It doesn’t depend on the size of the sample and it doesn’t change with time. So we imagine going in forward one half-life at a time from ZERO years: 10 years, 20 years, 30 years, etc.Carbon-14 is radioactive, with a half-life of about 5,700 years.For more information on cosmic rays and half-life, as well as the process of radioactive decay, see How Nuclear Radiation Works.

So carbon by definition has six protons, but the typical isotope, the most common isotope of carbon is carbon-12. And then that carbon dioxide gets absorbed into the rest of the atmosphere, into our oceans. When people talk about carbon fixation, they're really talking about using mainly light energy from the sun to take gaseous carbon and turn it into actual kind of organic tissue.

­The carbon-14 atoms that cosmic rays create combine with oxygen to form carbon dioxide, which plants absorb naturally and incorporate into plant fibers by photosynthesis.

Animals and people eat plants and take in carbon-14 as well.

But what's interesting is that a small fraction of carbon-14 forms, and then this carbon-14 can then also combine with oxygen to form carbon dioxide.

And carbon-14 is constantly doing this decay thing. So over the course of 5,730 years, roughly half of them will have decayed. Well, if you know that all living things have a certain proportion of carbon-14 in their tissue, as kind of part of what makes them up, and then if you were to find some bone-- let's just say find some bone right here that you dig it up on some type of archaeology dig.