A Survival Guide to the Misinformation Age: Scientific Habits of Mind by David J. Helfand

Author:David J. Helfand [Helfand, David J.]
Language: eng
Format: epub, mobi, pdf
Tags: Teaching, Mathematics/Study &#38, MAT030000, Science/Philosophy and Social Aspects, SCI075000
Publisher: Columbia University Press
Published: 2016-02-15T23:00:00+00:00

THE POISSON DISTRIBUTION

In some experiments, the goal is simply to count events that are occurring at random times and compare this to the known average rate at which they are expected to occur. One of the important examples of this is in using the radioactive decay of atomic nuclei as clocks to date ancient materials. We now know the age of the Earth to better than 1 percent through the application of such techniques and have dated the Shroud of Turin (the putative burial cloth of Jesus) to the 1350s (when church documents show it was forged by an artist in the employment of a corrupt bishop). In these applications, we use the fact that each type of radioactive nucleus decays at a precisely determined average rate, although the individual decays happen at random moments. For example, the heavy isotope (see box 10.5) of carbon-14 (C-14) will have half of its atoms decay over an interval of 5,730 years. We can determine how much of the C-14 breathed in by a plant (or the linen made from it) is left by counting the number of decays (signaled by the emission of a high-energy electron) and thus determine the age of the sample directly.

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