1. Radioactive Dating

2. Amount of Parent Isotope Present Amount of Daughter Isotope Present Decay

3. Amount of Parent Isotope Present Amount of Daughter Isotope Present Will DECREASE

4. Decay Amount of Parent Isotope Present Amount of Daughter Isotope Present Will DECREASE

5. Decay Amount of Parent Isotope Present Amount of Daughter Isotope Present Will DECREASE Will INCREASE

6. Decay Amount of Parent Isotope Present Amount of Daughter Isotope Present Will DECREASE Will INCREASE

7. Ratio of: will INCREASE INCREASE

8. Ratio of: will INCREASE INCREASE

12. Good to 50 000 years

13. Good to 5 billion years

15. Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO 2 ). Most of the carbon in the atmosphere consists of the stable isotope carbon–12, but a very small fraction is a radioactive isotope called carbon–14. The ratio of in the atmosphere has been relatively constant for the last 50 000 years.

16. Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO 2 ). Most of the carbon in the atmosphere consists of the stable isotope carbon–12, but a very small fraction is a radioactive isotope called carbon–14. The ratio of in the atmosphere has been relatively constant for the last 50 000 years.

17. Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO 2 ). Most of the carbon in the atmosphere consists of the stable isotope carbon–12, but a very small fraction is a radioactive isotope called carbon–14. The ratio of in the atmosphere has been relatively constant for the last 50 000 years.

18. Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO 2 ). Most of the carbon in the atmosphere consists of the stable isotope carbon–12, but a very small fraction is a radioactive isotope called carbon–14. The ratio of in the atmosphere has been relatively constant for the last 50 000 years.

19. Carbon from the Environment

20. While they are still alive, the ratio of remains the same as it is in the environment.

21. When an organism dies, it stops getting fresh carbon from the environment.

22. Remains as it is

23. Decreases as it decays

24. As the object gets older, the ratio of gradually decreases over time.

25. Carbon–14 nuclei undergo beta decay:

32. 5730 y

33. 50% of its original carbon–14 will still be present

34. 5730 y

36. A rib-bone from an archeological site was analyzed. By measuring the ratio of in the sample and comparing it to that in the environment, archeologists calculated that 12.0% of its original remained. How old is the bone?

37. 12.0%

39. 17 500 y

40. 17 500 years old