Radioactive Dating?
A sample of igneous rock is found to contain the radioactive parent and daughter isotopes uranium, ^235U, and lead, ^207Pb, in the ration of 12.5%:87.5%. Assuming that no ^207Pb was present when the rock first formed, estimate the age of this sample.
Answer: 2.14 billion years old
How did they get that? I know the half life formula, which we did in math, but I guess the ratio part is confusing me. Thanks!
Don’t worry about the ratio. All that means in this context is that 87.5% of the Uranium has decayed into lead. This is also equal to 7/8. Every half-life, approximately one-half of the material will decay. Since there is only one eighth left, that means that three half lives have passed. (The first decays 1/2, the second decays 1/4, and the third decays 1/8, leaving 1/8.) The half-life of U-235 is 7.038×108 y, or 703.8 million years. Multiplying that by three gives 2.14 billion years.
Radiometric Dating age of the earth
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Radioactive Dating (Home Use) $17.99 Radioactive or radiometric dating is a method of estimating the age of fossils, human artifacts or geologic formations by analyzing the tiny amounts they contain of certain radioactive elements. This program uses animation to help explain the key underlying concepts, including radioactive decay and half-life. A Coronet release.(For Home Use Only)This product is manufactured on demand using DVD-R r… |
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Radioactive Dating $54.95 Radioactive or radiometric dating is a method of estimating the age of fossils, human artifacts or geologic formations by analyzing the tiny amounts they contain of certain radioactive elements. This program uses animation to help explain the key underlying concepts, including radioactive decay and half-life. A Coronet release.This product is manufactured on demand using DVD-R recordable media. Am… |
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Radioactive dating: An entry from Thomson Gale’s Gale Encyclopedia of Science, 3rd ed. $1.95 The “Gale Encyclopedia of Science” is written at a level somewhere between the introductory sources and the highly technical texts currently available. This six-volume set covers all major areas of science and engineering, as well as mathematics and the medical and health sciences, while providing a comprehensive overview of current scientific knowledge and technology. Alphabetically arranged … |
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