A child mummy is found high in the Andes and the archaeologist says the child lived more than 2, years ago. How do scientists know how old an object or human remains are? What methods do they use and how do these methods work? In this article, we will examine the methods by which scientists use radioactivity to determine the age of objects, most notably carbon dating. Carbon dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 50, years old.
Half Life Calculator
By: Jessika Toothman. Prior to the development of radiocarbon dating , it was difficult to tell when an archaeological artifact came from. Unless something was obviously attributable to a specific year -- say a dated coin or known piece of artwork -- then whoever discovered it had to do quite a bit of guesstimating to get a proper age for the item. The excavator might employ relative dating, using objects located stratigraphically read: buried at the same depth close to each other, or he or she might compare historical styles to see if there were similarities to a previous find. But by using these imprecise methods, archeologists were often way off.
How Accurate is Carbon Dating?
In this section we will explore the use of carbon dating to determine the age of fossil remains. Carbon is a key element in biologically important molecules. During the lifetime of an organism, carbon is brought into the cell from the environment in the form of either carbon dioxide or carbon-based food molecules such as glucose; then used to build biologically important molecules such as sugars, proteins, fats, and nucleic acids. These molecules are subsequently incorporated into the cells and tissues that make up living things. Therefore, organisms from a single-celled bacteria to the largest of the dinosaurs leave behind carbon-based remains.
This included cloth fibers, bone, bits of wood and charcoal. Libby had realized that since all living things had a relatively constant carbon 14 to carbon 12 ratio as found in the atmosphere. Carbon 14 is a radioactive isotope type of atom and carbon 12 was a stable isotope. The reason was that plants took on carbon dioxide CO2 through photosynthesis and animals did so through breathing, eating plants and eating other animals. Libby knew that when a plant or animal died it would stop absorbing carbon.