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Carbon Dating By: Kelly Davenport, John Kolenda, Rosalie Tolentino, David McCracken.

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Presentation on theme: "Carbon Dating By: Kelly Davenport, John Kolenda, Rosalie Tolentino, David McCracken."— Presentation transcript:

1 Carbon Dating By: Kelly Davenport, John Kolenda, Rosalie Tolentino, David McCracken

2 Definition of Carbon Dating Carbon Dating: a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon 14; believed to be reliable up to 40,000 years Carbon Dating: a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon 14; believed to be reliable up to 40,000 years Based on the rate of decay of the carbon isotope 14 (14C)

3 How Carbon14 is made Cosmic rays enter the earth's atmosphere. They then collide with an atom in the atmosphere, creating a secondary cosmic ray in the form of an energetic neutron. These energetic neutrons collide with nitrogen atoms. When the neutrons collides a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon 14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons). Cosmic rays enter the earth's atmosphere. They then collide with an atom in the atmosphere, creating a secondary cosmic ray in the form of an energetic neutron. These energetic neutrons collide with nitrogen atoms. When the neutrons collides a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon 14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).

4 How Carbon Dating Works The carbon content of living matter is constantly renewed so the proportion of carbon 12 to carbon 14 is the same The carbon content of living matter is constantly renewed so the proportion of carbon 12 to carbon 14 is the same The rate Carbon 14 forms seems to be constant. Therefore by measuring the ratio between carbon 12 and the carbon 14 in a dead organism and comparing it to the ratio in living things, a measurement of time is made. Because the rate of decay for carbon 14 is 57,000 years, carbon dating is only reliable for dating things up to 60, 000 years old. As soon as a living organism dies, it stops taking in new carbon. The rate Carbon 14 forms seems to be constant. Therefore by measuring the ratio between carbon 12 and the carbon 14 in a dead organism and comparing it to the ratio in living things, a measurement of time is made. Because the rate of decay for carbon 14 is 57,000 years, carbon dating is only reliable for dating things up to 60, 000 years old. As soon as a living organism dies, it stops taking in new carbon.

5 Half Life of Carbon Dating Half-Life refers to the time taken to lose half of radioactivity: the time a radioactive substance takes to lose half its radioactivity through decay. Half-Life refers to the time taken to lose half of radioactivity: the time a radioactive substance takes to lose half its radioactivity through decay. The Half-Life of Carbon 14 is 5730 years. For example, if a relatively large sample of Carbon 14 was left untouched for 5730 years, half of it would remain and the other half would decay. The Half-Life of Carbon 14 is 5730 years. For example, if a relatively large sample of Carbon 14 was left untouched for 5730 years, half of it would remain and the other half would decay.

6 Half Life Analogy Half Life is to Carbon 14 as exponentially decreasing over time is to mathematics Half Life is to Carbon 14 as exponentially decreasing over time is to mathematics

7 Examples of Carbon Dating Uses Carbon Dating can be extremely useful to archeologists when they need to know the approximate date of a fossil or any other object. Carbon Dating can be extremely useful to archeologists when they need to know the approximate date of a fossil or any other object. Some examples of when carbon dating is used: to find the ages of trees, mummies, fossils, or any other organic material Some examples of when carbon dating is used: to find the ages of trees, mummies, fossils, or any other organic material

8 Bibliography gy/dating/radio_carbon.html gy/dating/radio_carbon.html gy/dating/radio_carbon.html gy/dating/radio_carbon.html 14.htm 14.htm 14.htm 14.htm astr.gsu.edu/hbase/nuclear/cardat.html astr.gsu.edu/hbase/nuclear/cardat.html astr.gsu.edu/hbase/nuclear/cardat.html astr.gsu.edu/hbase/nuclear/cardat.html perts/ae403.cfm perts/ae403.cfm perts/ae403.cfm perts/ae403.cfm


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