This document discusses radiometric dating and how it is used to determine the absolute ages of rocks and minerals. It explains key concepts such as radioactivity, half-life, and how comparing ratios of radioactive isotopes like carbon-14 and carbon-12 can be used to calculate radiocarbon dates for samples. Radiometric dating relies on the fact that radioactive isotopes decay at a constant rate and comparing the amounts of parent and daughter isotopes allows the age of a sample to be estimated.

1. 12.3 Dating with Radioactivity

2. Radioactivity
• The spontaneous decay of certain unstable
atomic nuclei.

3. Half- life
• The time required for one half of the atoms of
a radioactive substance to decay

4. Radiometric dating
• The procedure of calculating the absolute ages
of rocks and minerals that contain radioactive
isotopes.

5. Radiocarbon dating
• Method for determining age by comparing the
amount of carbon-14 to the amount of
carbon-12 in a sample

6. Key Concept
• When nuclei are unstable, they spontaneously
break apart, or decay, in a process called
radioactivity.

7. Key Concept
• A half-life is the amount of time necessary for
one half of the nuclei in a sample to decay to
its stable isotope.

8. Key Concept
• Each radioactive isotope has been decaying at
a constant rate since the formation of the
rocks in which it occurs

9. Key Concept
• As the uranium decays, atoms of the daughter
product are formed, and measurable amounts
of lead eventually accumulate.

10. Key Concept
• An accurate radiometric date can be obtained
only if the mineral remained in a closed
system during the entire period since its
formation.

11. Key Concept
• When an organism dies, the amount of
carbon-14 gradually decreases as it decays. By
comparing the ration of carbon- 14 to carbon-
12 in a sample, radio0carbon dates can be
determined.