# Radiometric Dating

Explain how radiometric dating works — radioactive isotopes decay at a known rate (half-life), so measuring the ratio of parent to daughter isotope in a rock or fossil gives an absolute age; distinguish between carbon-14 (useful up to ~50,000 years) and uranium-lead (useful for millions to billions of years)

Builds on: Rock Layers & Relative Dating (hard, https://ai.page/c/rock-layers-and-relative-dating/en.md), Atoms, Elements & Compounds (soft, https://ai.page/c/atoms-elements-and-compounds/en.md)

Concept id: radiometric-dating. Subject: science. Licence: CC BY-SA 4.0.

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