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With the following question we wish to see whether the style in which newspaper reports are written enable people to determine in what newspaper they were published. On the following page you will find a report that recently appeared in a national newspaper. Please read the report carefully and then indicate in what newspaper you think this report appeared. Rain drop mystery solved Further research has been published showing that the behavior of rain drops as they fall has not been properly understood so far. Falling rain drops flatten out into a pancake shape, turn into a little pouch and finally splash apart. French researchers have demonstrated in Nature Physics (20 July) that the perceived distribution of a lot of small and a few large drops in a rain shower is the consequence of large drops falling apart, shortly after they emerge from the cloud. Until now it was assumed that this distribution is a consequence of internal collisions. Last month Mexican researchers had already reported in Geophysical Research Letters that many drops hit the ground at very different speeds than previously thought. The size distribution of drops in rain showers of various calibres was first established in 1904 by Wilson A. Bentley. Bentley caught the drops in an open container with a bedding of loose wheat flour that encapsulated each drop when it fell, thus retaining its shape for research. Filtration paper turned out to work just as well, following callibration with standard drops. Drops with a size exceeding a critical diameter turn out to flatten into a pancake shape as they fall, which is then blown into a pouch shape with a heavy donut-like ring from below. In the last stage the pouch disintegrates, leaving the donut as the largest drop. Further calculations suggest that this mechanism produces exactly the distribution of drop sizes that are found in the field. An essential point is that the French claim that this distribution already emerges directly beneath the cloud base. This is at odds with the result of the Mexican study. The Mexicans discovered that large rain drops often hit the ground at speeds lower than previous assumed, and smaller drops with higher speeds, because they are created through internal collisions at the last moment.

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