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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Radiometric Dating means practising the idea at the table with a simple hands-on check. We will demo once, then your child tries.
Materials: Fossil photos or a printout of a trackway / skeleton; Pencil and sticky notes. 1. Say the goal of Radiometric Dating in plain words once. 2. Adult points to one fossil clue and says what environment or behavior it suggests. 3. Child reads three fossil clues and writes one evidence-based inference each. 4. Fresh check: one fresh fossil-clue inference. Record and stop. Done: three inferences tied to a visible fossil clue. Proof: parent note of examples and results. Stop: End after the fresh check; keep optional challenge for another day.
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USGS · Practice link — not the full lesson
About volcanoes
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About volcanoes supports Radiometric Dating. An adult previews and guides; this is a learning page, not a scored quiz.
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Before you openAsk the learner one fact they learned and one question they still have.
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Public USGS page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
USGS. “About volcanoes.” External page; Gakuva does not copy, host, embed, or redistribute materials.
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Check understanding
- 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