The amount of carbon-14 in the air has stayed the same for thousands of years.
There is a small amount of radioactive carbon-14 in all living organisms because it enters the food chain.
Along with hydrogen, nitrogen, oxygen, phosphorus, and sulfur, carbon is a building block of biochemical molecules ranging from fats, proteins, and carbohydrates to active substances such as hormones.
All carbon atoms have a nucleus containing six protons.
Ninety-nine percent of these also contain six neutrons.
The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.
Materials that originally came from living things, such as wood and natural fibres, can be dated by measuring the amount of carbon-14 they contain.
At an archaeological dig, a piece of wooden tool is unearthed and the archaeologist finds it to be 5,000 years old.is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.It can be used on objects as old as about 62,000 years.Carbon-14 dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 50,000 years old.It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities.Once an organism dies, it stops taking in carbon-14.