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Amount of Parent Isotope Present Amount of Daughter Isotope Present Will DECREASE
Citation preview
Radioactive Dating
Amount of ParentIsotope Present
Amount of Daughter
Isotope PresentDecay
DecayAmount of
ParentIsotope Present
Amount of Daughter
Isotope Present
Will DECREAS
E
DecayAmount of
ParentIsotope Present
Amount of Daughter
Isotope Present
Will DECREAS
E
DecayAmount of
ParentIsotope Present
Amount of Daughter
Isotope Present
Will DECREAS
E
Will INCREAS
E
DecayAmount of
ParentIsotope Present
Amount of Daughter
Isotope Present
Will DECREAS
E
Will INCREAS
E
Ratio of: will INCREASEINCREASE
Daughter IsotopeParent Isotope
Ratio of: will INCREASEINCREASE
Daughter IsotopeParent Isotope
Good to 50 000 years
Good to 5 billion years
Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO2).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.
126C
14 126 6C / C
146C
Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO2).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.
126C
14 126 6C / C
146C
Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO2).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.
126C
14 126 6C / C
146C
Earth’s atmosphere contains the element carbon, mainly in the form of carbon dioxide (CO2).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.
126C
14 126 6C / C
146C
Carbon from the
Environment
While they are still alive, the ratio of remains the same as it is in the environment.
14 126 6C / C
When an organism dies, it stops getting fresh carbon from the environment.
Remainsas it is
126C
Remainsas it is
126C
Decreases as it decays
146C
As the object gets older, the ratio of gradually decreases over time.
14 126 6C / C
As the object gets older, the ratio of gradually decreases over time.
14 126 6C / C
Carbon–14 nuclei undergo beta decay:144 07 1
16 N eC
144 07 1
16 N eC
144 07 1
16 N eC
144 07 1
16 N eC
144 07 1
16 N eC
144 07 1
16 N eC
5730 y
144 07 1
16 N eC
5730 y
50% of its original
carbon–14 will
still be present
144 07 1
16 N eC
5730
y
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?
14 126 6C / C
146C
12.0%12.0
%
12.0%
17 500 y
17 500 y
17 500 years old