Estimates age of organic remains from the remaining fraction of carbon-14, half-life 5730 years.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
Radiocarbon dating estimates the age of organic material from the proportion of carbon-14 that remains. Living organisms take up carbon-14 from the atmosphere and maintain a constant ratio, but after death the carbon-14 decays with a half-life of 5730 years. Measuring the remaining fraction of carbon-14 relative to stable carbon gives the age of the sample. The method is accurate for samples up to about 50,000 years old, beyond which too little carbon-14 remains. It is widely used in archaeology and geology.
Key ideas: Living organisms maintain 14C / 12C at about 1.2 x 10^-12 from cosmic-ray production (14N + n gives 14C + p). After death, 14C decays with t1/2 = 5730 years. Age t = (t1/2 / 0.693) x ln(N0 / N). Useful for organic material up to about 50000 years old. Example: 25 percent remaining means 2 half-lives, or 11460 years.
Common mistakes and connections: Students use it for rocks or fossils millions of years old (use U-Pb or K-Ar instead), and apply it to dinosaurs. Another error is assuming constant atmospheric 14C; calibration with tree rings is needed. The calculation is first-order decay. Fossil fuel burning dilutes 14C, and bomb tests raised it.
With a 5730 year half-life, carbon-14 in dead material falls to 25 percent after 11,460 years, which dates samples up to about 50,000 years old. The interactive lesson shows this as a live animation or chart.
A sample retaining 25 percent of its original carbon-14 has undergone two half-lives, so it is about 11,460 years old.
Estimates age of organic remains from the remaining fraction of carbon-14, half-life 5730 years.
Radiocarbon Dating is a intermediate topic in Atomic Structure & Periodicity. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Atomic Structure & Periodicity first: Half-life, Nuclear Fission, Nuclear Fusion.
The next topics in Atomic Structure & Periodicity are Magic Numbers and Island of Stability.
Yes. The interactive lesson includes a self-check question on Radiocarbon Dating, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Radiocarbon Dating is topic 110 of 115 in Atomic Structure & Periodicity.