Radioactive dating example
Simply counting the number of rings will give one a fairly good idea of the age of the tree.Periods of heavy rain and lots of sunshine will make larger gaps of growth in the rings, while periods of drought might make it difficult to count individual rings. When a given quantity of an isotope is created (in a supernovae, for example), after the half-life has expired, 50% of the parent isotope will have decomposed into daughter isotopes.Mountains, erosion, and variations in climate were considered to be punishment for the sins committed by humanity.
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
Libby received the Nobel Prize in Chemistry for his work in 1960.
Trees undergo spurts in growth in the spring and summer months while becoming somewhat dormant in the fall and winter months.
When a tree is cut down, these periods are exhibited in a cross section of the trunk in the form of rings.
Research has been ongoing since the 1960s to determine what the proportion of in the atmosphere has been over the past fifty thousand years.