Module 8
1. Module 8
1.14. Page 5
Module 8—Nuclear Decay, Energy, and the Standard Model of the Atom
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In order to verify the accuracy of radioactive dating it must be tested using samples of known age. For example, could radioactive dating confirm the age of a piece of wood from a mummiform coffin from Egypt dated, on stylistic grounds, to be from the Ptolemaic period, 332 B.C.? Could it accurately predict the age of acacia wood from the tomb of Zozer at Sakkara, which is known to be 4650 ±75 years old?
In all such tests, observations matched predictions, verifying the accuracy of radiocarbon dating. Once verified, the methodology could be applied to measure the age of any organic sample, such as the Burmis tree in Alberta.
In order to determine the age of a sample using radioactive dating, we will assume that the amount of carbon-14 in the ancient wood, when it died, was identical to the amount of carbon-14 in a similar sample of living wood today. In other words, the amount of carbon-14 in the atmosphere has not changed significantly in the past 5000 years. In reality scientists and archaeologists carefully adjust for variations in atmospheric carbon-14 by comparing values to known values from ice cores, deep-sea sediments, and tree growth rings (dendrochronology).
Module 8: Lesson 2 Assignment
Remember to submit your answers to RC 1 and RC 2 to your teacher as part of your Module 8: Lesson 2 Assignment.
RC 1. Predict the percentage of remaining carbon-14 (half-life = 5730 years) in an ancient wood sample that is known to be 2500 years old.
RC 2. Explain how this prediction could be used to measure the accuracy of radiocarbon dating.
Module 8: Lesson 2 Assignment
Remember to submit the Module 8: Lesson 2 Assignment to your teacher.