What year was Mt. Rushmore completed?
How old are the rocks of Mt. Rushmore?
Radiometric dating relys on the fact that elements have ___________.
What is a half-life?
Carbon dating measures what form of carbon?
What element do we measure for long periods of time?
What is the daughter isotope of uranium?
What country was the oldest rock on the planet found?
Radiometric dating is reliable.
Use your own words to describe a "half-life"