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)
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“If your child was told a dinosaur bone was dated using uranium-lead radiometric dating, could they explain what that means — what is decaying, why the rate of decay is useful, and roughly why scientists don't use carbon-14 for 70-million-year-old bones?”
Full guide and materials
- Activity. 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)
What to notice. Defines half-life as the time for half the radioactive parent isotope to decay to the daughter isotope • Explains that the parent:daughter ratio in a sample gives an estimate of absolute age • Distinguishes carbon-14 (for recent organic material) from uranium-lead or potassium-argon (for deep geological time), explaining why carbon-14 cannot be used for dinosaur bones
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If your child was told a dinosaur bone was dated using uranium-lead radiometric dating, could they explain what that means — what is decaying, why the rate of decay is useful, and roughly why scientists don't use carbon-14 for 70-million-year-old bones?
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)
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- Defines half-life as the time for half the radioactive parent isotope to decay to the daughter isotope
- Explains that the parent:daughter ratio in a sample gives an estimate of absolute age
- Distinguishes carbon-14 (for recent organic material) from uranium-lead or potassium-argon (for deep geological time), explaining why carbon-14 cannot be used for dinosaur bones
“If your child was told a dinosaur bone was dated using uranium-lead radiometric dating, could they explain what that means — what is decaying, why the rate of decay is useful, and roughly why scientists don't use carbon-14 for 70-million-year-old bones?”
Curriculum record
- Type
- Conceptual
- Subject
- Science
- Domain
- Dinosaurs & Paleontology
- Age range
- Ages 11–13