Carbon 14 Dating

Carbon 14 Dating

Intoduction

Road workers in Eastern China dug up a 700 yr old mummy. They say the mummy was from the "(1) Ming Dynasty - the ruling power in China between 1368 and 1644". As your reading this article in the daily news paper, you question yourself "How do they know it was 700 years old?" The way we determine the age of an ancient artifact is a process called Carbon 14 Dating. Carbon 14 dating was discovered by "(2)Willard Frank Libby, a chemist who developed the first method for dating a material that had a biological orgin" Carbon 14 Dating is a way of determining the age of an archeological artifacts of a biological origin dating up to 50,000. (3) We can use Carbon 14 dating on Bones, cloth, wood, and plant fibers'.

How is it used

* How does it work, from a nuclear / chemical perspective?

The Nitrogen in our atmosphere makes up about 78 percent of the earths air. When cosmic rays enter our atmosphere it may collide with one of our atoms in our atmosphere. It also can create a second cosmic ray to form an energetic neutron. When these energetic atoms collide with Hydrogen-14 it creates Carbon 14. Carbon 14 then combines with oxygen creating carbon dioxide. Through photosynthesis plants naturally absorb the carbon dioxide combined with carbon 14, and then consumed my humans and animals. When the animals, or humans consume a plant the Carbon 14 is consistently decaying, but is always being replaced when more plants are consumed, and or animals.

Most of the carbon that exists in today's world is mostly carbon 12, carbon 14 exist only in small amounts of our environment. Carbon 14 in animals and plants are consistently decaying. As the animal or plant breaths oxygen, and eats, the carbon 14 is replaced. When a plant or animal dies it stops bringing in new carbon 14, the remaining carbon 14 that's in the organisms body slowly decays. Scientists can determine the age of the artifact by comparing the ratio of Carbon 14, and carbon 12.

Limitations

There are several limitations of carbon 14 dating. Firstly, carbon dating can only be used on objects that were or are living, meaning that man-made objects cannot be tested. Secondly, the sample tested must be quite large in size, because part of the object is broken down and lost when it is cleaned and distilled. The loss of the part may cause an inaccurate date given to the object. Thirdly, Changes in the atmosphere, particularly the thinning of the ozone, cause more Carbon 14 to be produced, so the standard measurement of the Carbon 14 existing in the time used to compare with the fossil must be transferred to the correct