Carbon dating is a type of radioactive dating used to identify the age of human, animal, and plant remains. This method uses an isotope of carbon, carbon 14, which is formed when cosmic rays enter our atmosphere, strike nitrogen, and change it into another element. This isotope is radioactive and has a half-life of 5,730 years. This means that the quantity of carbon 14 in an organism will be cut in half every 5,730 years. All organic matter has both carbon 12(the most abundant form of carbon) and carbon 14, which is much less in abundance. Since C12 does not decay scientists compare the ratio of C12 in a sample to the amount of C14 left and they then can estimate how much C14 was there to begin with. Today, the ratio in the atmosphere is about one C14 atom for every one trillion C12 atoms. Here is an example, if a fossil is discovered and there is one C14 atom for every two trillion C12 atoms, you can assume that the fossil is 5,730 years old since the radioactive carbon has decayed one half-life. Basically, scientists date organic material based on the amount of C14 left in a sample compared to the amount of C12.
There are several flaws with this method of dating. One is that the method only works for organic material that is 60,000 years old or younger because by the time something reaches that age, the amount of C14 left becomes untraceable. Scientists can only account for around 10 half-lives of C14. Also, we are assuming that the ratio of C12 atoms to C14 was the same in the past as it is today. Since radioactive carbon is forming 28-37 percent faster than it decays, our environment has not yet reached equilibrium and the amount of C14 in our environment is constantly increasing. We have no way of undoubtedly knowing how much C14 was originally in a sample.
Questions:
1. What is the instrument used to detect C14 and briefly explain how it works.
2. Into what element does Carbon 14 decay?
3. What is another way to find the age of organic material?
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1. Accelerator mass spectrometry uses accelorated ions to determine the amount of Carbon 14 in a sample.
ReplyDelete2. Carbon 14 decays into Nitrogen 14
3. For material older than 50,000 years, whether it is organic or not, stratigraphy is used to measure its age. Stratigraphy uses the layers of rock and sediment where the material was found to determine its age.
1. Accelerator mass spectrometry or AMS. It uses accelerated ions to measure the carbon 14 in a sample.
ReplyDelete2. Into the stable (non-radioactive) isotope nitrogen-14.
3. By using stratigraphy.
1) The instrument used to detect C14 is the Accelerator mass spectrometer. This spectrometer detects positions of ions through magnetation, to obtain the amount of C14 in a substance.
ReplyDelete2) Carbon 14, which is unstable, decays into Nitrogen 14, which is stable. This occurs through beta decay
3)You can find the age of organic material through stratigraphy. Stratigraphy is the study of rocks and rock layers. Through this study researchers can discover what an area of land was like back during the time that the rock came from.