If a Bigtooth Maple were cut down on Mount Lemmon in 2016 and it had 400 rings, you would know the tree started growing in 1616. What if it's been used to build a home or a ship or a bonfire?
The rings could still tell how many years the tree lived, but not necessarily when. He set out on a series of expeditions across the southwest to bridge the gap between contemporary wood and wood beams from the ruins of civilizations long gone.
The concept behind radiocarbon dating is rather simple.
While organisms live, they incorporate radioactive carbon-14 from the atmosphere.
The same applies to marine organisms, although with some well-understood subtleties.
After the organism dies, the carbon-14 decays in a predictable way.
"Every year the trees in our forests show the swing of Time's pendulum and put down a mark.
They are chronographs, recording clocks, by which the succeeding seasons are set down through definite imprints," he wrote in the pages of National Geographic.
The aim here is to provide clear, understandable information relating to radiocarbon dating for the benefit of K12 students, as well as lay people who are not requiring detailed information about the method of radiocarbon dating itself.By measuring the ratio of carbon-14 to stable carbon-12, scientists can then determine when the organism in question died.When Libby developed the radiocarbon dating technique, he validated the method by comparing measured carbon ratios (carbon-14/carbon-12) from artifacts of known age with predictions of the ratio expected by assuming the decay rate.Rasmus Nyerup's quote reminds us of the tremendous scientific advances which have taken place in the 20th century.In Nyerup's time, archaeologists could date the past only by using recorded histories, which in Europe were based mainly on the Egyptian calendar.