# Radiocarbon dating assumes that the carbon 14carbon 12 ratio

The carbon-14 isotope would vanish from Earth's atmosphere in less than a million years were it not for the constant influx of cosmic rays interacting with molecules of nitrogen (NFigure 1: Diagram of the formation of carbon-14 (forward), the decay of carbon-14 (reverse).

Carbon-14 is constantly be generated in the atmosphere and cycled through the carbon and nitrogen cycles.

So I said maybe it's 5,730 years since this bone was part of a living animal, or it's roughly that old.

Now, when I did that, I made a pretty big assumption, and some you all have touched on this in the comments on You Tube on the last video, is how do I know that this estimate I made is based on the assumption that the amount of carbon-14 in the atmosphere would have been roughly constant from when this bone was living to now?

The entire process of Radiocarbon dating depends on the decay of carbon-14.

This process begins when an organism is no longer able to exchange Carbon with their environment.

And the way that you can make that calibration, because it turns out it isn't perfectly constant, the way that you can make that calibration, there's two ways, and I have pictures here of both of them, one is to look at tree things. And I'm told this will work up to about 10,000 years. I don't know of any 10,000 year old trees, I don't think anyone does, but maybe there's some remains of old trees.

The technique of radiocarbon dating was developed by Willard Libby and his colleagues at the University of Chicago in 1949.

In contrast, living material exhibit an activity of 14 d/min.g.

Thus, using Equation \(\ref\), \[\ln \dfrac = (1.21 \times 10^) t \nonumber\] Thus, \[t= \dfrac = 2 \times 10^3 \text \nonumber\] From the measurement performed in 1947 the Dead Sea Scrolls were determined to be 2000 years old giving them a date of 53 BC, and confirming their authenticity.

And so the question is, is the amount of carbon-14 in the atmosphere and in the water, and in living plants and animals, is it constant?

And if it isn't constant, how do you calibrate your measurement so you can actually figure out how much carbon-14 there is relative to living plants and animals at that time?