Fire and water to unlock ‘internal clocks’ of archaeological objectsMay 20th, 2009 - 12:20 pm ICT by ANI
Washington, May 20 (ANI): A team of scientists has developed a new way of dating archaeological objects, by using fire and water to unlock their ‘internal clocks’.
The scientists, from the University of Manchester and the University of Edinburgh, call this technique as ‘rehydroxylation dating’, which can be used to date fired clay ceramics like bricks, tile and pottery.
Working with The Museum of London, the team has been able to date brick samples from Roman, medieval and modern periods with remarkable accuracy.
They have established that their technique can be used to determine the age of objects up to 2,000 years old - but believe it has the potential to be used to date objects around 10,000 years old.
The method relies on the fact that fired clay ceramic material will start to chemically react with atmospheric moisture as soon as it is removed from the kiln after firing.
This continues over its lifetime causing it to increase in weight. The older the material, the greater the weight gain.
In 2003, the Manchester and Edinburgh team discovered a new law that precisely defines how the rate of reaction between ceramic and water varies over time.
The application of this law underpins the new dating method because the amount of water that is chemically combined with a ceramic provides an ‘internal clock’ that can be accessed to determine its age.
The technique involves measuring the mass of a sample of ceramic and then heating it to around 500 degrees Celsius in a furnace, which removes the water.
The sample is then monitored in a super-accurate measuring device known as a microbalance, to determine the precise rate at which the ceramic will combine with water over time.
Using the time law, it is possible to extrapolate the information collected to calculate the time it will take to regain the mass lost on heating - revealing the sample’s age.
According to Lead author Dr Moira Wilson, Senior Lecturer in the School of Mechanical, Aerospace and Civil Engineering (MACE), “We are extremely excited by the potential of this new technique, which could become an established way of determining the age of ceramic artifacts of archaeological interest.”
“The method could also be turned on its head and used to establish the mean temperature of a material over its lifetime, if a precise date of firing were known. This could potentially be useful in climate change studies,” Dr Wilson added. (ANI)
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