Like by looking at a certain artefact scientists can determine that it is from 2100 years ago, how are they so sure of the accuracy.
In: Chemistry
It can’t be just any artifact, it must be organic.
Plants get CO2 from the air and CO2 has a certain level of C-14.. animals eat plants, both die and get incorporated into the soil.
Once the carbon is fixed in organic material this is a moment in time. C-14 decays
All living things absorb both types of carbon; but once it dies, it will stop absorbing. The C-12 is a very stable element and will not change form after being absorbed; however, C-14 is highly unstable and in fact will immediately begin changing after absorption. Specifically, each nucleus will lose an electron, a process which is referred to as decay. This rate of decay, thankfully, is constant, and can be easily measured in terms of ‘half-life’.
Half-life refers to the amount of time it takes for an object to lose exactly half of the amount of carbon (or other element) stored in it. This half-life is very constant and will continue at the same rate forever. The half-life of carbon is 5,730 years, which means that it will take this amount of time for it to reduce from 100g of carbon to 50g – exactly half its original amount. Similarly, it will take another 5,730 years for the amount of carbon to drop to 25g, and so on and so forth. By testing the amount of carbon stored in an object, and comparing to the original amount of carbon believed to have been stored at the time of death, scientists can estimate its age.
Lately we’ve been putting more and more old carbon in the air, so it’s not exactly accurate. it’s more of an estimate and you’d use other data to determine approximate age such as where it’s found, surrounding artifacts, etc.
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