# How do we use carbon 14 for radioactive dating

Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies.

Carbon-14 is also passed onto the animals that eat those plants.

After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.

Carbon-14 has a half-life of 5,730 ± 40 years, meaning that every 5,700 years or so the object loses half its carbon-14.

Where t is the age of the fossil (or the date of death) and ln() is the natural logarithm function.

If the fossil has 35% of its carbon 14 still, then we can substitute values into our equation.

But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.

Because the time it takes to convert biological materials to fossil fuels is substantially longer than the time it takes for its in the atmosphere, which attained a maximum in 1963 of almost twice what it had been before the testing began.When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon 14.Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death.Samples from the past 70,000 years made of wood, charcoal, peat, bone, antler or one of many other carbonates may be dated using this technique. The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.