Shortlisted entries 2012
2. From Fire to Eternity
For over twenty thousand years people have been using fire to make durable, utilitarian and often beautiful objects out of clay. Fired clay has been used to form decorative or religious items, household objects, even buildings made of bricks and tiles. This image shows a tile from Victoria train station, Manchester; the crazing on the glaze has occurred because the underlying clay ceramic has expanded as it has aged, but the brittle glaze has not. Research at Manchester has discovered that all fired clay material expands because it reacts chemically with atmospheric moisture at a constant and predictable rate over time. This has implications for the durability of fired-clay objects, whether they are brick buildings or Chinese porcelain. It also means that it is possible to calculate how much time has passed since a fired-clay object was made; this is rehydroxylation dating, and it will revolutionise understanding of our past.