数学家教你如何科学地切蛋糕

You've had your share of birthdays so you know perfectly well how to cut a cake, right?你已经过了好几次生日了，所以你觉得你很懂怎么切蛋糕，对吗？Don't count on it.千万别这么想。As British mathematician Alex Bellos explains in a fun new video from his Numberphile series, the traditional approach to divvying up a cake -- cutting a series of wedges -- just doesn't cut it from a scientific standpoint，or from the standpoint of flavor.在“数字狂”系列短片里，英国数学家亚历克斯·贝洛斯详细解释了把蛋糕切成多个楔形的传统方法，既不是科学的切法，也不是一个保留口感的切法。"You're not maximizing the amount of gastronomic pleasure that you can make from this cake," he says in the video, adding that once you cut out a wedge, you expose the inside of the cake to the air -- and it dries out."你没有从蛋糕上极大限度地获得美食带来的愉悦，" 在短片里他这样说道，并补充说一旦你切下一块蛋糕，蛋糕的内部就暴露在空气中——然后它就会被风干。A better way, Bellos says, has existed for more than a century. In 1906 the journal Nature ran a letter from Francis Galton in which the celebrated British polymath offered -- "for his own amusement and satisfaction" -- what he considered a superior method of cutting a cake. The goal, he wrote, was to cut it "so as to leave a minimum surface to become dry."贝洛斯说，在一个多世纪以前，就已经有一个更妙的切蛋糕的方法。在1906年，《自然杂志》刊登了一篇来自英国著名学者弗朗西斯·高尔顿的报告——“出于他的自娱自乐”——他在研究一个最绝妙的切蛋糕的方法。他写道，这个目标就是"让蛋糕会被风干的暴露面积尽可能缩小。"The cake should be cut in parallel lines, starting in the centre, with the rectangular segments of the cake then taken out and eaten.科学的切蛋糕方法是：在中间平行切两刀，把中间切出的矩形蛋糕拿出来吃掉。This would allow the cake to then be closed, provided it is one with icing, keep the sponge inside sealed and retaining its freshness.这样剩余的蛋糕还可以拼在一起，像一个完整的奶油蛋糕那样存放。用这种方法就可以保持蛋糕内部密封保鲜。