Start Carbon dating formula for kids

Carbon dating formula for kids

Most carbon on Earth is not radioactive, but a very small percentage is.

The carbon-14 decays with its half-life of 5,700 years, while the amount of carbon-12 remains constant in the sample.

By looking at the ratio of carbon-12 to carbon-14 in the sample and comparing it to the ratio in a living organism, it is possible to determine the age of a formerly living thing fairly precisely. So, if you had a fossil that had 10 percent carbon-14 compared to a living sample, then that fossil would be: t = [ ln (0.10) / (-0.693) ] x 5,700 years t = [ (-2.303) / (-0.693) ] x 5,700 years t = [ 3.323 ] x 5,700 years Because the half-life of carbon-14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old.

­ ­As soon as a living organism dies, it stops taking in new carbon.

Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.

Other useful radioisotopes for radioactive dating include Uranium -235 (half-life = 704 million years), Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14 billion years) and Rubidium-87 (half-life = 49 billion years).

The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy.

However, radioisotope dating may not work so well in the future.