Ch. 16-2 Radiometric dating does not measure the age of an individual atom. It is a measure of the age of a quantity of atoms—a statistic. As with any statistical measure, its values may deviate around an average. Imagine that one sample of rock is dated ten different ways. Nine of the tests yield an age close to 225,000 years. One test yields an age of 3.2 million years. Do the nine consistent results imply that the one that deviates is incorrect, or does the one odd result invalidate the nine that are consistent?

Radiometric dating is a technique used to determine the age of rocks. Geologists have used this technique to determine that:   A. The universe started with the "Big Bang."   B. Earth is about 6.2 trillion years old, and life appeared on Earth about 4.9 trillion years ago.   C. Earth is about 4.6 billion years old, and life appeared on Earth about 4.1 billion years ago.   D. Earth is about 4.6 million years old, and life appeared on Earth about 4.4 million years ago.   E. Earth is about 6.2 thousand years old, and life appeared on Earth about 6 thousand years ago.

Comment on the remark "Evolution seems to be reversible," which refers to industrial melanism.

Using the rule of 1500, what is a more precise rate?

"The half-life of the C14 isotope is 5730 years. 19,000 years after an animal dies the fraction of carbon in its bones that is C14 will have decreased to about ______ percent of its original level."     2   5   10   16