How Water Can Identify Murder Victims and Fake Scotch - Issue 42: Fakes
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One of the criteria that make a Scotch a Scotch is that it’s made with Scottish water. That means that a clever connoisseur should be able to tell whether her drink is authentic by tracing the source of its H2O molecules. But how? After it’s collected and filtered of impurities, water is water, right? Not exactly. The elements hydrogen and oxygen appear in nature in various forms, called isotopes, which differ in neutron number. By measuring the relative abundance of these isotopes in a water sample using a technique called mass spectrometry, scientists can determine its “isotope ratio.” And as it turns out, the isotope ratio of water varies dramatically from place to place. Scientists first noticed this in the 1950s, when they started collecting freshwater samples from around the world, (...)