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One of the uses of radioactive elements is to date items. For example, Carbon-14

ID: 579723 • Letter: O

Question

One of the uses of radioactive elements is to date items. For example, Carbon-14 is used to date organic material. Uranium-238 is another radioactive isotope used for dating. It is primarily used to date the earth itself. According to scientists, using Uranium-238, the earth is approximately 4.3 billion years old. Your assignment this week is to research how Uranium-238 is used to date the earth; what assumptions were made in the calculations? Read both benefits and disadvantages to the method. Based on your research do you agree with an earth age of 4.3 billion years old. (Make sure you explain your reasoning.) Include a works cited page (your resources)

Explanation / Answer

Uranium-Lead dating is a very common mode of radiometric dating used. Mineral ZIRCON (belongs into the group nesosilicates) is used to perform this dating method. Zircon strongly rejects Lead, and only incorporated thorium atoms and uranium. So we can assume that all the lead content found in zircon is the product of radioactive decay of uranium. Uranium 238 decays to Lead 206 ( 238U to 206Pb). So from the lead content present in zircon, the age of earth can be calculated as the half-life of Uranium is known (radioactive decays are first-order reaction, so reaction rate is independent of concentration, only depends on rate constant which can be easily calculated)

The assumption we take here:

Advantage:

Ability to date an object without destroying it

Disadvantage:

We are not sure that the assumptions here are correct.

From my research, I think this method is one of the best available methods to find the earth’s age. Since we cannot depend on carbon dating as organic or life forms were not present at the birth of earth. Also, no other methods other than radiometric dating is been found. And multiple persons have reported this age from their research.

Reference:

https://en.wikipedia.org/wiki/Uranium%E2%80%93lead_dating

https://en.wikipedia.org/wiki/Age_of_the_Earth

https://answersingenesis.org/age-of-the-earth/dating-methods/

http://www.tech-faq.com/radiometric-dating.html