1. Determining Absolute Age
12/7/16
Determining Absolute Age
objective: I will model rates of radioactive decay through a graphing activity.
PAGE 45

2. Absolute Age
absolute age- the exact numeric age of an object or event

4. Radiometric Dating
method of using radioactive decay to measure absolute age

5. Radiometric Dating
rocks contain unstable radioactive isotopes that emit particles (decay)

6. Half-Life
time required for half of a sample of radioactive isotopes to break down (decay)
half-life is always constant for a particular isotope

8. Half-Life parent isotope- original radioactive isotope
daughter isotope- newly formed stable isotope

9. Half-Life
scientists compare the ratio of the parent and daughter isotopes to calculate absolute age
higher % of daughter isotope = more half-lives
higher % of parent isotope = less half-lives

11. Radioactive Isotopes
Uranium-238 (238U): very long half-life (4.5 billion years)
useful for dating geologic samples more than 10 million years old
Carbon-14 (14C): short half-life (5730 years)
used to date once living samples less than 70,000 years old

12. Output Activity (Page 44)
Illustrate Figure 4 from page 194 of the Holt Textbook
Create a key to represent the parent and daughter isotopes
Label each part of the diagram with:
the % of parent isotope that has decayed into the daughter isotope
the % of the parent isotope that has not decayed

13. Output Activity (Page 44)
Using the diagram from page 194, answer the following question. Write both the question and answer.
1) Scientists discover a fossil and use radiometric carbon dating to find its age. The fossil contains a 3 to 1 ratio of the daughter isotope, Nitrogen-14, compared to its parent isotope, Carbon-14. How old is the fossil? (the half-life of Carbon-14 is 5,730 years)

14. Extra Credit
Answer questions #28,29,30 from page 203 in your textbook.
Each correct answer earns 3 points on tomorrow’s Quiz.
Write your answers on a separate piece of paper and submit them when you are finished.
You must show your work!