2. Chapter: Clues to Earth’s Past Table of Contents Section 3: Absolute Ages of Rocks Section 1: Fossils Section 2: Relative Ages of Rocks

6. Alpha and Beta Decay Absolute Ages of Rocks 3

7. Alpha and Beta Decay Absolute Ages of Rocks 3

10. Radiometric Ages Absolute Ages of Rocks 3

17. Section Check 3 Question 1 __________ age is the age in years of an object. A. Absolute B. Calculated C. Derived D. Relative NC: 5.01

18. Section Check 3 Answer The answer is A. Geologists use properties of atoms in specific materials to determine absolute age. NC: 5.01

19. Section Check 3 Question 2 What is meant by the term “half-life” of an isotope?

20. Section Check 3 Answer The half-life of an isotope is the time it takes for half of the atoms in the isotope to decay.

21. Section Check 3 Question 3 What information must you have in order to conduct radiometric dating? Answer You must have an isotope with an appropriately short or long half-life. You must also know the isotope’s half-life and be able to measure the ratio of parent isotope to daughter product.