Geology 1A West Valley College

A. Use the graph paper attached.

B. Label the X-axis with number of half-lives (0, 1, 2, 3 … 10).

C. Label the Y-axis with number of parent atoms (0 to 1000) and daughter atoms (0 to 1000).

1.The half-life of the radioactive element to be graphed is given as 5730 years. Label the number years corresponding to each half-life (0, 5730, 11460, etc.).

2. Begin with 1000 atoms of radioactive parent element and 0 atoms of stable daughter product. Plot points to draw the decay curve, showing the decrease in the number of parent atoms through ten half-lives.

3. Label each point with the number of parent atoms remaining.

4. Draw in the decay curve using a ruler to draw the line between each pair of points.

5. Plot points to draw the accumulation curve, showing the increase in the number of atoms of stable daughter product through ten half lives.

6. Label each point with the number of daughter atoms remaining.

7. Draw in the accumulation curve using a ruler to draw the line between each pair of points.

8. How many years are equal to 5 half-lives?

9. How many parent atoms will be left after 5 half-lives?

10. How many daughter atoms will be left after 5 half-lives?

11. At what point in time (number of half-lives) will the number of parent atoms be equal to the number of daughter atoms?

12. At what point in time (number of years) will the number of parent atoms be equal to the number of daughter atoms?

13. At what point in time (number of half-lives) will the number of daughter atoms be exactly three times the number of parent atoms?

14. At what point in time (number of years) will the number of daughter atoms be exactly three times the number of parent atoms?

15. How many daughter atoms will be present after 3 half-lives?

16. How many parent atoms will be present after 3 half-lives?

17. How many half-lives are equal to 22,920 years?

18. What element has a half-life of 5730 years?

19. What is the element to which 14C decays?

20. If you have 125 atoms of parent, how many daughter atoms will be present?

21. If you have 125 atoms of parent, how old (number of years) is the sample?

22. If you have 750 parent isotopes remaining, how many daughter atoms will be present?

23. If you have 750 parent isotopes remaining, how many have lives have elapsed?

24. What is the age of a sample with 750 parent isotopes remaining?