Carbon 14 dating 1 | Life on earth and in the universe | Cosmology & Astronomy | Khan Academy

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Carbon-14 is formed in the atmosphere and absorbed by organisms, decaying over time back into nitrogen-14, allowing scientists to estimate the age of organic material through carbon dating based on the number of half-lives undergone. This method provides a way to determine the age of archaeological finds by comparing the amount of carbon-14 in a sample to living organisms.

Insights

  • Carbon-14 is a radioactive isotope formed in the atmosphere and absorbed by living organisms, decaying over time and used to determine the age of organic materials through comparing decay rates.
  • The process of carbon dating relies on measuring the amount of carbon-14 in a sample to estimate its age by calculating the number of half-lives it has undergone, providing a valuable tool for dating archaeological artifacts accurately.

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Recent questions

  • How is Carbon-14 formed?

    Through cosmic particles interacting with nitrogen.

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Summary

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Carbon-14 Dating: Estimating Age Through Decay

  • Carbon-14 is formed in the Earth's atmosphere through cosmic particles interacting with nitrogen, replacing a proton and forming a neutron, creating carbon-14.
  • Carbon-14 is constantly formed in the atmosphere, combining with oxygen to create carbon dioxide, which is absorbed by plants and enters the food chain.
  • While alive, organisms incorporate carbon-14 into their tissues through consumption, but once they die, the carbon-14 begins to decay back into nitrogen-14 through beta decay.
  • The rate of carbon-14 decay is used to determine the age of organic material, with a half-life of roughly 5,730 years, meaning half of the carbon-14 will decay in that time frame.
  • By comparing the amount of carbon-14 in a sample to living organisms, the age of the sample can be estimated based on the number of half-lives it has undergone.
  • Finding a sample with 1/2 the expected carbon-14 indicates it is around 5,730 years old, while a sample with 1/4 the expected amount has undergone two half-lives, making it approximately 11,460 years old.
  • This method of carbon dating provides a way to estimate the age of archaeological finds based on the amount of carbon-14 present in the sample.
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