While this soaking removes some good material too, it does not change the C ratio, but it is altered the same way in the calibration samples too.For example, while the Catholic Church was unwilling to let scientists burn a square inch piece of the Shroud of Turin, when mass spec technology advanced, it was willing to let them burn a thread, and that was all that was needed. Finally, one reads the age from a calibration chart of age vs. In the Radiocarbon journal the ratio is reported, so readers can calibrate for themselves.
In addition to tree rings, scientists have looked at what are called lake varves in Northern Sweden.
All plants take in carbon from carbon dioxide in the atmosphere. A carbon-14 atom is radioactive; it eventually loses an electron and a neutrino and changes to nitrogen-14.
Its half-life is 5,730 30 years, so it never has nor can be used to date carbon samples millions of years old.
Now trees shed their leaves in the fall, and the leaves that fall in a lake form a thin layer at the bottom.
This happens annually, and thus very thin annual layers are deposited. More snow is deposited in summer, when the air is wetter, than in winter.