1. Absolute Dating Chapter 3, Sec.3

2. Process to find the approximate age of rocks or fossils

3. Atoms Smallest part of matter Made of protons, neutrons, electrons Center called the nucleus

4. Everything is made of atoms

6. Protons, neutrons in nucleus Electrons move around nucleus

8. Every element has a diff. # of protons

10. Isotopes Atoms of the same element with different # of neutrons

11. Radioactive Decay Most atoms are stable Some are unstable and breakdown or decay (radioactive)

12. High energy particles are given off Can damage cells, organs, etc.. X-rays, gamma rays, electrons, protons, neutrons

14. Decay occurs at a constant rate called half-life

15. Half-life The time it takes for one-half of a sample to decay

17. Problem I start with 10 grams of a sample It’s half-life is 20 years After 20 years, how much left? After 40 years, how much left 5 grams 2.5 grams

19. Some unstable isotopes decay into stable isotopes

22. 3 radioactive dating methods Uranium-Lead Method Potassium-Argon Method Carbon-14 Method