Theory
Scattering
Atoms
αβγ decay
Decay Series
Law
Half-life
Geiger
Carbon-14
Fission
Chain Reaction
Nuclear Energy
Nuclear reactors
Fusion

The half-life of carbon-14 is 5,700 years.

Because of its half-life, Carbon-14 is only reliable for dating objects up to about 50,000 years old.

A small % of Cardon Dioxide is made with Carbon14.

Carbon14 enters plants through photosynthesis. Carbon14 enters animals when they eat plants.

Supplies of Carbon14 are replenished by cosmic ray.

What is carbon-14 dating?
Scientists use radioactivity to determine the age of many ancient objects. The technique they use is called carbon-14 dating. It is used in dating things such as bone, cloth and wood or in fact anything that was made of matter that once lived. Because the half-life of carbon-14 is 5,730 years, it is only reliable for dating objects up to about 50,000 years old.

How is carbon-14 formed?                          Proton




Neutron
 
                                          Carbon-14

When a neutron collides with and is captured by a nucleus of nitrogen, a proton is ejected and radioactive carbon-14 is formed.

How does carbon-14 get to so many places?
The carbon-14 atoms created by cosmic rays combine with oxygen to form carbon dioxide, which plants absorb naturally by photosynthesis. Animals and people eat plants and take in carbon-14 as well. The ratio of normal carbon (carbon-12) to carbon-14 in the air and in all living things at any given time is nearly constant. The carbon-14 atoms are always decaying, but they are being replaced by new carbon-14 atoms at a constant rate. Today, your body has a certain percentage of carbon-14 atoms in it, and all living plants and animals have the same percentage.

How is the dating done?
As soon as a living organism dies, it stops taking in new carbon. The ratio of carbon -12 to carbon -14 at the time of death is the same as every other living thing, but the carbon -14 decays and is not replaced. Since carbon -14 decays, while the amount of carbon -12 remains constant in the sample, then the ratio of carbon -12 to carbon -14 in the sample diminishes as time passes. By comparing the ratio for the sample under investigation to the ratio in a living organism, it is possible to determine the age of the sample.

How is the date calculated?
When the measurements have been taken, the results are substituted into the formula
t = [ ln (N/No) / (-0.693) ] x T
where t is the age of the sample and T is the half-life of Carbon-14