Here's why:
* Carbon-14 is naturally occurring: It's formed in the upper atmosphere when cosmic rays interact with nitrogen atoms.
* Carbon-14 decays at a constant rate: This means it has a known half-life of approximately 5,730 years.
* Living organisms incorporate Carbon-14: Plants take in Carbon-14 during photosynthesis, and animals eat plants (or other animals that have eaten plants). This means living things contain a relatively constant amount of Carbon-14.
* When an organism dies, the Carbon-14 starts to decay: It no longer takes in new Carbon-14.
* Measuring the ratio of Carbon-14 to Carbon-12: By comparing the amount of Carbon-14 remaining in a sample to the amount of stable Carbon-12, scientists can determine how long ago the organism died.
This technique, known as radiocarbon dating, is a powerful tool for understanding the history of life on Earth and is widely used in archaeology, geology, and other fields.
