Radioactive dating and relative dating are two methods used by scientists to determine the age of rocks and fossils, but they operate on different principles.
Radioactive dating, also known as radiometric dating, involves measuring the amount of radioactive isotopes present in a sample and knowing their half-lives. This allows scientists to calculate the actual age of the sample in years. For example, carbon-14 dating is commonly used to date organic materials up to about 50,000 years old by measuring the remaining carbon-14 isotopes.
On the other hand, relative dating does not give an exact age but rather determines the sequence of events. It involves looking at the layers of rocks and fossils found within them, using the principle of superposition, which states that in an undisturbed sequence of rocks, the oldest layers are at the bottom and the youngest are at the top. By examining these layers and the fossils contained within, scientists can establish a relative timeline of when various organisms existed.
In summary, radioactive dating provides an exact age based on scientific measurements, while relative dating gives a chronological order of events without specifying exact dates.