Extend your thinking: The slow decay of radioactive materials can be used to find the age of rocks, fossils, and archaeological artifacts. In a process called radiometric dating, scientists measure the proportions of radioactive atoms and daughter atoms in an object to determine its age. Carbon-14 is a useful isotope because it is found in wood, ash, bone, and any other organic materials. You can use the Half-life Gizmo to model the decay of Carbon-14, which has a half-life of approximately 6,000 years (actual value is 5,730 years). In the Gizmo, select User chooses half-life and Theoretical decay. Set the Half-life to 6 seconds (to represent 6,000 years) and the Number of atoms to 100. Use the Gizmo to estimate the age of each of the objects below. For these questions, each second in the Gizmo represents 1,000 years. Description Age (years) Egyptian papyrus with 63% of its original carbon-14 atoms Aboriginal charcoal with 22% of its original carbon-14 atoms. Mayan headdress with 79% of its original carbon-14 atoms Neanderthal skull with 3% of its original carbon-14 atoms