ChemTeam: Half-life problems involving carbon
Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of. carbon Carbon with 6 protons and 8 neutrons is called carbon (14C). Radiometric dating is relatively cheap (about $/sample), takes about a month to achieve . and others, working on events in the Holocene, there is a further problem. Research has shown was dated to C14 BP; but shells, lying on the. Older carbon dating techniques directly detected decays of C14 atoms. The problem: If the material is too old, the small amount of C14 present.
Though radiocarbon dating is startlingly accurate for the most part, it has a few sizable flaws.
The technology uses a series of mathematical calculations—the most recognizable of which is known as half-life—to estimate the age the organism stopped ingesting the isotope. Unfortunately, the amount of Carbon in the atmosphere has not been steady throughout history. In fact, it has fluctuated a great deal over the years. This variation is caused by both natural processes and human activity. Humans began making an impact during the Industrial Revolution.
Radiocarbon Dating: A Closer Look At Its Main Flaws
The isotope decreased by a small fraction due to the combustion of fossil fuels, among other factors. The answer to the problem of fluctuating amounts of this important isotope is calibration. Standard calibration curves are now used for more accurate readings. These curves indicate the changes in Carbon throughout the years and modifies the end result of the tests to reflect that.
Though the calibrated date is more precise, many scholars still use the uncalibrated date in order to keep chronologies consistent in academic communities. As the lecture detailed, it is only accurate from about 62, years ago to 1, A.
There is a sizable amount of time before and after that period that cannot be investigated using this method. Also, archaeologists cannot use their hands to touch the samples or smoke near them. As it turns out, Miller's research group obtained their sample in quite a remarkable way.
In fact, the creationist posed as chemists in order to secure a number of fragments of fossilized dinosaur bone from a museum of natural history, misrepresenting their own research in the process of doing so.
Radiocarbon dating - Wikipedia
When the museum provided the bone fragments, they emphasized that they had been heavily contaminated with "shellac" and other chemical preservatives. Miller and his group accepted the samples and reassured the museum that such containments would not be problematic for the analysis at hand. They then sent it to a laboratory run by the University of Arizona, where radiocarbon dating could be carried out. To get the scientists to consider their sample, the researchers once again pretended to be interested in the dating for general chemical analysis purposes, misrepresenting their research.
Let's take a little pause to consider the general issue of misrepresenting your own research. It is understandable that Miller et al. Thus, it appears that Miller et al.
Radiocarbon Dating: A Closer Look At Its Main Flaws | Great Discoveries in Archaeology
This, of course, raises some ethical questions, but let's brush these aside for now. What exactly are we dating here? Sample contamination and general trustworthyness After the samples were submitted by the laboratory, Miller et al.
Miller let assured the professor that the analysis was still of interest to the group. The issue of contaminations is quite a serious one, as can be seen in this paper by Hedges and Gowlett sorry, paywalled!!!
- How Accurate is Carbon Dating?
- Considering Contamination
- Radiocarbon dating
I quote quote also reproduced in the paper by Lepper that I linked earlier: At a horizon of 40, years the amount of carbon 14 in a bone or a piece of charcoal can be truly minute: Consequently equally small quantities of modern carbon can severely skew the measurements. Contamination of this kind amounting to 1 percent of the carbon in a sample 25, years old would make it appear to be about 1, years younger than its actual age.
Such contamination would, however, reduce the apparent age of a 60,year-old object by almost 50 percent. Clearly proper sample decontamination procedures are of particular importance in the dating of very old artifacts It is clear that the sample provided by Miller did not under go any 'sample decontamination procedures' at all, and it is therefore strongly questionable to which extent it can be used to obtain a good estimate of the age of the bones.