# Carbon dating for

Some things you'll be assessed on include which radioisotope of carbon is used in carbon dating, the length of the half-life of carbon-14, and what you can determine about isotopes based upon half-life.Free 5-day trial Ever wondered how scientists know the age of old bones in an ancient site or how old a scrap of linen is?This is why radiocarbon dating is only useful for dating objects up to around 50,000 years old (about 10 half-lives).Radioactive carbon-14 is continually formed in the atmosphere by the bombardment of cosmic ray neutrons on nitrogen-14 atoms.Radiocarbon dating is a method used to date materials that once exchanged carbon dioxide with the atmosphere; in other words, things that were living.Carbon-14 is a radioactive isotope and is present in all living things in a constant amount.

Carbon dating was used routinely from the 1950s onward, and it confirmed the age of these historical remains.For example, if you start off with 1000 radioactive nuclei with a half-life of 10 days, you would have 500 left after 10 days; you would have 250 left after 20 days (2 half-lives); and so on.The half-life is always the same regardless of how many nuclei you have left, and this very useful property lies at the heart of radiocarbon dating. The graph below shows the decay curve (you may recognize it as an exponential decay) and it shows the amount, or percent, of carbon-14 remaining.As a member, you'll also get unlimited access to over 70,000 lessons in math, English, science, history, and more.Plus, get practice tests, quizzes, and personalized coaching to help you succeed.