1. Absolute-Age Dating
Chapter 21.3

2. Absolute-Age dating allows geologists to assign a numerical age to rocks, fossils, or artifacts. Radioactive decay is the process by which radioactive elements break apart to form elements with smaller nuclei. The half-life of a radioactive element is the amount of time for half of the atoms in the sample to break apart and form smaller nuclei.

3. Radiometric Dating:
- By knowing the half-life of the radioactive element in a rock and assuming the amount present when the rock formed, scientists can assign an absolute-age to the rock.
Radiocarbon Dating:
- Uses carbon-14, a radioactive form of carbon.
- Carbon-14 accumulates in the tissues of living things until they die.
- By measuring the amount remaining, you can estimate how long ago it died.
Video – Radiometric Dating (1:38 min)