radiocarbon

Everyday

1. (science) A kind of carbon, called carbon-14, that is slightly radioactive and slowly breaks down over thousands of years. tree →
2. (adjective) Using carbon-14 to find out how old something is: «radiocarbon dating». tree →

In the lessons

In science and history lessons radiocarbon dating tells how old once-living things are (wood, bone, cloth), up to about 50,000 years. All living things take in carbon-14; after they die it slowly disappears, so scientists measure what is left. Phrases: «radiocarbon dating», «radiocarbon age», «radiocarbon test».

Examples

• Radiocarbon dating showed the wooden boat was 3,000 years old. tree →
• Scientists used radiocarbon to date the bones in the cave. tree →
• Radiocarbon dating only works on things that were once alive. tree →
• The Shroud of Turin was tested by radiocarbon dating in 1988. tree →
• You cannot use radiocarbon to date dinosaur bones; they are far too old. tree →
• Half of the radiocarbon in a sample breaks down in about 5,730 years. tree →

Note

Uncountable. Also called carbon-14 or C-14. Maths: its half-life is about 5,730 years, so after 5,730 years half is left, after 11,460 years a quarter is left. Myth: radiocarbon dates dinosaurs — false; dinosaurs are tens of millions of years old, so other methods are used on rocks.