1. Absolute Dating

2. Radioactive ParentStable Daughter Product Half Life Values U-238Pb-20645 Billion Years U-235Pb-207713 Million Years Th 232Pb-20814.1 Billion Years Rb 87St-8747 Billion Years K - 40Ar-401.3 Billion Years C -14N-145730 Years

3. In this example, each time this happened, 10,000 years had gone by. So if it happened 3 times, then the object is: 3 x 10,000 = 30,000 yrs old Parent: 16  8  4  2 Daughter: 0  8  12  14 Parent: 16  8  4  2 Daughter: 0  8  12  14

4. Absolute Dating – What Proportion is Left?