Most of us don't even think about all the "stuff" that populates our lives -- until we trip over something. As a teenager, Mark Miodownik started out much like all of us, until a stranger on the tube slashed through five layers of his clothing with a razor blade that was "not much bigger than a postage stamp" -- giving him a huge scar down his back and an unexpected focus to his life.
"Since the stabbing incident, I have spent the vast majority of my life obsessing about materials", writes Miodownik. "A million questions poured out", at least a thousand of which gave rise to his latest book, Stuff Matters: Exploring the Marvelous Materials That Shape Our Man-Made World [Viking (an imprint of Penguin Books), 2013; Guardian Bookshop; Amazon UK; Amazon US/audiobook CD US]. The author, a UCL professor and materials scientist, uses chemistry, history, psychology and good old fashioned storytelling to explore the nature of the materials that compose some of the stuff that occupies most peoples' everyday lives, prompting readers to view the most ordinary objects -- drinking glasses, stainless steel spoons, a bar of chocolate and even pencils -- with a newfound appreciation.
Self-healing concrete has these bacteria embedded inside it along with a form of starch, which acts as food for the bacteria. Under normal circumstances these bacteria remain dormant, encased by the calcium silicate hydrate fibrils. But if a crack forms, the bacteria are released from their bonds, and in the presence of water they wake up and start to look for food. They find the starch that has been added to the concrete, and this allows them to grow and replicate. In the process they excrete the mineral calcite, a form of calcium carbonate. This calcite bonds to the concrete and starts to build up a mineral structure that spans the crack, stopping further growth of the crack and sealing it up. [p. 67-68]
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