67 research outputs found

    Scientific U-turns: eight occasions when science changed its mind

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    The Scientific Method is the series of processes by which hypotheses, ideas and theories are shown to be true beyond a reasonable scientific doubt. Most science ‘fact’ is expressed in terms of probabilities rather than certainties. Thus, by means of statistical calculations, researchers aim to determine whether an observed association between two events or characteristics may have occurred by chance (coincidence), whether they frequently occur together (correlation) or whether they occur together because one causes the other (causative relationship). In this article we review the Scientific Method and consider the statistical tests that are applied. We then focus on the occasions when science changes its mind and review eight such occurrences

    An overview of some natural products with two A-level science club natural products experiments

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    Natural products are ubiquitous in nature but do not form a large proportion of theA-level syllabuses in the UK. In this article we briefly discuss a small selection of natural products, focusing on alcohols, aldehydes and ketones, and alkaloids. We then outline two natural product experiments that are suitable for A-level chemistry clubs or similar. Experiment 1 is the isolation and analysis of caffeine from tea, and Experiment 2 is the extraction and characterisation of a volatile oil, eugenol, from cloves. These experiments include a variety of laboratory techniques, including steam distillation, determination of melting point, thin-layer chromatography andcolumn chromatography, infrared spectroscopy and ultraviolet spectrophotometry

    To teach or not to teach?

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