Dating bricks

If this were so, the width of the annual growth rings would show changes in synchronism with the sunspot numbers.

He established a laboratory in the university of Arizona, at Tucson, to study tree-rings.

Unfortunately, after many years of analysis he was not able to confirm the correlation he sought.

Nevertheless, the laboratory was able to demonstrate many interesting properties of ring widths and their relationship with various aspects of climate and other natural phenomena and, of course, their use in the accurate dating of timber.

First they found that newly fired bricks, aged naturally in air over several months, contract to their original dimensions after a couple of hours of heating at 450ºC.

Dry heating nonetheless restored the bricks to their original size.This suggests that heat treatment might return even old bricks to their freshly fired state.Finally, the team was surprised to find a similar relationship between shrinking and age for building blocks 20 years old, 120 years old, or Roman samples 1,900 years old. Bricks swell very slowly as they age, because they absorb moisture. How much they shrink indicates how old they are because it is proportional to how long they have been wicking up water, argue Moira Wilson of the University of Manchester Institute of Science and Technology, UK, and colleagues.The researchers performed a series of experiments with new and old bricks.

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