Wending A Wet Way

LORD Charles Bowen was a grandson of the essayist Sir Richard Steele, a brilliant lawyer, and something of a wit.

LORD Charles Bowen was a grandson of the essayist Sir Richard Steele, a brilliant lawyer, and something of a wit.

He once described a certain metaphysicist, for instance, as "a blind man in a dark room, looking for a black hat which isn't there". More to the point as regards today's soliloquy, was his observation on a rain fall and on human nature.

The rain it raineth on the just

And also on the unjust fells

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But chiefly on the just, because

The unjust steals the just's umbrella.

It is but one small step from a moral not like this to a question that must have trouble most of us from time to time when caught in the open in a shower of rain do you get wetter if you run towards shelter, thereby getting a soaking down the front, than if you take your time, encountering less rain per second, but for a longer spell? Four meteorologists from Reading University have found the answer using calculus.

They assume for the purpose of their argument, that the rain is falling vertically, and that its intensity is constant over time. A person standing still when exposed to such a downpour, will have rain falling directly on his horizontal surfaces if, on the other hand, he moves, he will also collide with any raindrops in his way. To simplify their calculations, the team approximate the average son by an imaginary rectangular block of appropriate dimensions, and they work out a total quantity of water en-countered by this person block as it moves at various speeds, over given distances, and for a variety of different rates of rainfall. The answers are very interesting indeed.

Obviously if you just stand still and brave the rain indefinitely, you will get very wet indeed. But if you move, the total amount of water encountered tums out to decrease rapidly as you increase your rate of progress to a brisk walk because the faster you travel, the quicker you reach shelter. But surprisingly perhaps, beyond a brisk walk, any further increase in speed has very little effect on how wet you get if you run like mad, you will reach the shelter very quickly, but at this higher speed you will have collected more raindrops on the way, and consequently got wetter down the front.

Bearing in mind that we wish to achieve the best result with a minimum of effort, the best tactic, it seems, is to head for the nearest shelter at six miles per hour, or slightly more than walking pace. If you move more slowly, you will catch more rain and to go any faster is simply just not worth the extra energy required.