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  3. If you are caught in a downpour, it is better to run for shelter than walk, researchers in the US advise. This may sound obvious

If you are caught in a downpour, it is better to run for shelter than walk, researchers in the US advise. This may sound obvious

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问题     If you are caught in a downpour, it is better to run for shelter than walk, researchers in the US advise. This may sound obvious, but an earlier study in Britain suggested that you would get just as wet running as walking.
    In 1995, Stephen Belcher of the University of Reading and his students calculated how much water falls on top of your head and how much you sweep up on your front as you move forward. Obviously, you would get wettest standing still, and less wet the faster you moved. But the Reading team found that the benefits of running faster than about 3 metres per second—which they described as a walking pace—were tiny.
    Thomas Peterson and Trevor Wallis, meteorologists at the National Climatic Data Center in Asheville, North Carolina, had a hunch that this was wrong. They realized that the Reading team had overestimated the average walking pace, so they reworked the calculations for a walking pace of 1.5 metres per second and a running speed of 4 meters per second.
    Peterson and Wallis conclude in the latest issue of Weather that a walker would get 16 per cent wetter than a runner over a distance of 100 meters in drizzle. In heavy rain, this would rise to 23 per cent. When the researchers allowed for the way that runners tend to lean forward, sheltering the front of their bodies but increasing the rainfall on their backs, they found that a walker would get 36 per cent wetter than a runner in heavy rain.
    Not content with theory alone, Peterson and Wallis decided to test their ideas. " If verification requires an $ 80 million satellite, one may have to forgo verification, " says Peterson. "But if it involves a simple experiment, that’ s another matter. " Peterson and Wallis are roughly the same size. Wearing identical clothing, one ran 100 meters in heavy rain and the other walked.
    They weighed their clothes before and after the experiment. This showed that the walker bad absorbed 0.22 kilograms of water, while the runner had soaked up only 0. 13 kilograms. This is about 40 per cent less, is line with the model’ s predictions.
    Belcher says that his team’ s work was a bit of fun, and that apart from the confusion over what a typical walking speed is, their results were similar to those of Peterson and Wallis. "I’m delighted to see that their experiments gave results in qualitative agreement with the model," says Belcher.
    But why not just take an umbrella? For anyone thinking of taking the easy way out, Wallis has a warning: "Running with an umbrella has a negative impact on your aerodynamics. "  
They verified their model predictions by experimenting______.
选项 A、on themselves
B、with a satellite
C、on the twins of the same size
D、with sophisticated calculating devices
答案A
解析 第五段最后以及第六段叙述了Peterson和Wallis的实验，通过叙述可知两人是以自己为实验对象的。
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