Carbon dating a rock
When enough suitable trees are found, living or dead, the matching is completely accurate.
Then, we have wood for which we know the right answer.
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Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40.
So, anything more than about 50,000 years old probably can't be dated at all.
If you hear of a carbon dating up in the millions of years, you're hearing a confused report. Second, they rarely contain any of the original carbon.
The potassium-argon age of some meteorites is as old as 4,500,000,000 years, and volcanic rocks as young as 20,000 years old have been measured by this method.
A carbon-oxygen bond is more polar than a carbon-hydrogen bond, because the difference in electronegativity between carbon and oxygen is greater than the difference in electronegativity between carbon and hydrogen.
The C14 will undergo radioactive decay, and after 5730 years, half of it will be gone. So, if we find such a body, the amount of C14 in it will tell us how long ago it was alive. The method doesn't work on things which didn't get their carbon from the air.On the other hand, the abundance of argon in the Earth is relatively small because of its escape to the atmosphere during processes associated with volcanism.The potassium-argon dating method has been used to measure a wide variety of ages.Both of these man-made changes are a nuisance to carbon dating.If you hear of a living tree being dated as a thousand years old, that is not necessarily an example of an incorrect dating. Wood taken from the innermost ring really is as old as the tree. We can date things for which historians know a "right answer".