To determine the absolute age of rocks and fossils, scientists commonly use two main methods:
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Radiometric Dating: This technique measures the decay of radioactive isotopes in rocks. For example, carbon-14 dating is used for organic materials, while uranium-lead dating is often used for older rocks. By comparing the ratio of parent isotopes to daughter isotopes, scientists can calculate the age of the material.
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Dendrochronology: Also known as tree-ring dating, this method involves counting the annual growth rings of trees. Each ring represents one year, and by analyzing these rings, scientists can determine the age of a tree and also gather information about past climate conditions.
These methods help provide an accurate estimate of the age of geological materials and ancient life forms.