Isotopes and Radioactivity

Change the number of neutrons and you get an isotope — same element, different weight. Carbon-12 has 6 neutrons. Carbon-14 has 8 neutrons.

Carbon-14 decays with a half-life of 5,730 years — half of it transforms into nitrogen over that period. This makes it perfect for dating ancient objects up to about 50,000 years old. Scientists measure remaining Carbon-14 to determine an artifact's age.