Author Question: What are radioactive decay rates in minerals affected by? A) temperature and pressure B) ... (Read 153 times)

plus1

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What are radioactive decay rates in minerals affected by?
 
  A) temperature and pressure
  B) nothing
  C) variations in gravity and magnetism
  D) heat

Question 2

How have scientists determined the age of the Earth?
 
  What will be an ideal response?



rosiehomeworddo

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Answer to Question 1

Answer: B

Answer to Question 2

Answer: Eighteenth-century geologists, including James Hutton, applied scientific observations and principles to conclude that the geologic rock record requires that Earth be extraordinarily ancient. Lord Kelvin calculated Earth's age based on a conceptual model of how much the planet has cooled since its origin. His calculations suggested an age in the range of 20-40 million years. John Joly calculated the age of the oceans based on a conceptual model of how long it would take Earth's rivers to transport enough salt to account for the current saltiness of the ocean. His calculations suggested an age of 80-100 million years. Kelvin's and Joly's calculations were correct but included assumptions that could not be verified at the time of their work. Reconsideration of their assumptions shows that the ages they calculated are minimum values and, therefore, Earth must be still older.



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