1. Carbon-14 is Radioactive:
* C14 is a radioactive isotope of carbon. It decays over time, transforming into nitrogen-14 (N14).
* This decay happens at a constant rate, known as the half-life.
2. Half-life of Carbon-14:
* The half-life of C14 is approximately 5,730 years. This means that after 5,730 years, half of the original C14 in a sample will have decayed into N14.
* After another 5,730 years (a total of 11,460 years), half of the remaining C14 will decay, and so on.
3. Living Organisms and Carbon-14:
* Living organisms continuously take in carbon from their environment.
* This carbon includes a small but stable amount of C14, which is constantly replenished.
* As a result, the C14/C12 ratio in living organisms is roughly the same as the ratio in the atmosphere.
4. Death and Decay:
* When an organism dies, it no longer takes in carbon.
* The C14 present in the organism's remains starts to decay at a constant rate.
* The C14/C12 ratio in the fossil begins to decrease as the C14 decays.
5. Dating Fossils:
* By measuring the remaining C14 in a fossil and comparing it to the original C14/C12 ratio, scientists can estimate the time since the organism died.
* This method is called radiocarbon dating and is a powerful tool for understanding the age of fossils and archeological artifacts.
In Summary:
The C14/C12 ratio in fossils changes over time due to the radioactive decay of C14. This decay happens at a constant rate, allowing scientists to use the remaining C14 to estimate the age of the fossil.
