Science: Absolute Age of Rocks and Fossils Quick check.
Which quantity helps determine the absolute age of rocks and fossils?
1. the difference between the number of protons and neutrons in carbon-14
2. the ratio of carbon-12 to carbon-14
3. the ratio of protons to neutrons in carbon-14
4. the difference between the amounts of carbon-12 and carbon-14
The correct answer is 4. the difference between the amounts of carbon-12 and carbon-14.
To determine the absolute age of rocks and fossils, we rely on the principles of radioactive decay and the measurement of isotopes.
The correct answer is option 2: the ratio of carbon-12 to carbon-14.
Carbon dating is a commonly used method to determine the age of organic materials, such as fossils or remains of ancient civilizations. It relies on the fact that carbon atoms occur in different isotopes, with carbon-12 (12C) and carbon-14 (14C) being two of the most important isotopes of carbon.
Carbon-12 is stable and does not decay over time, but carbon-14 is a radioactive isotope that undergoes radioactive decay. This means that over time, carbon-14 atoms in a sample will break down and transform into nitrogen-14 (14N). By comparing the ratio of carbon-12 to carbon-14 in a sample, scientists can estimate how much time has passed since the death of the organism.
The half-life of carbon-14 is approximately 5730 years, meaning that after this time, half of the original carbon-14 will have decayed. By measuring the ratio of carbon-12 to carbon-14 in a sample and comparing it to the known ratio in living organisms, scientists can calculate the age of the sample.
Therefore, the answer that helps determine the absolute age of rocks and fossils is the ratio of carbon-12 to carbon-14 (option 2).