Carbon dating is a scientific method used to determine the age of ancient organic materials, such as bones, wood, or shells. It works by measuring the amount of carbon-14, a radioactive isotope of carbon, present in a sample. Living organisms continuously absorb carbon from their environment, but when they die, they stop taking in carbon, and the carbon-14 begins to decay at a known rate. By comparing the remaining carbon-14 in a sample to the expected levels in the atmosphere, scientists can estimate how long it has been since the organism died. This technique is useful for dating artifacts and fossils up to about 50,000 years old.