12 October 2009

Temperature tribulations

Hasok Chang's 2004 book Inventing Temperature tells the long and intriguing history of thermometry, the science of the measurement of temperature. First, thermometers had to be invented, followed by methods to calibrate them. But to calibrate a thermometer at least one reproducible phenomenon that always took place at the same temperature was needed. But how would one know that something, say the boiling of water, always took place at the same temperature if one didn't have a calibrated thermometer? This circularity was behind most of the hurdles the pioneering thermometrists had to overcome. Finally, temperature scales, a multitude of them, were devised—almost one by each independent thermometer maker.

I learned quite a bit from this book. Among the more interesting episodes were a series of experiments by Marc-Auguste Pictet in the late 18th century that demonstrated quite puzzlingly that cold, like heat, could be reflected from a mirror (for details, read this 1985 paper by Evans & Popp) and the potter Josiah Wedgwood's (Charles Darwin's grandfather) almost contemporaneous invention of a pyrometer to measure very high temperatures—it used small pieces of clay, the amount of shrinkage of which at a given temperature were supposed to have been reproducible.

I wish Chang's prose were a bit more straight and readable and the contents of the book a bit more uniform. The first 4 of the 6 chapters have 2 parts each: a historical narrative followed by an analysis that dwells into philosophical issues that I thought were boring and not always relevant. I confess I skipped most of the analyses.

Chang ends his book with a chapter on complementary science, his research program that intends, by utilizing the historical and philosophical aspects of a particular scientific area, physics, in his case, to "generate scientific knowledge in places where science itself fails to do so." I find Chang's ideas provocative, but will try to criticize them in detail in another post.

Also posted in a slightly different form on Amazon.

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