Recommended Reading
Ever wondered why we study probability theory and all that stuff about normal distributions? The "bell" shape of the normal distribution makes it a convenient choice for modelling a large variety of random variables encountered in practice. For sure, it's used throughout the social sciences and it's long been known that experimental error follows a normal distribution - a useful concept employed in manufacturing and industry for reducing waste and ensuring quality. However, as an elegant bit of maths it crops up in some of the most bizarre places.
Take a meandering river, yes those horse-shoe shaped things taught in Geography lessons that generate ox bow lakes when adjacent bends touch. It just so happens that a symmetrical meander can be modelled by the normal distribution curve. If the course of a meander is broken down into path segments then the probability of a change in direction for any segment is given by a normal distribution curve centred around zero. The probability distribution peaks at zero change in direction (most of a meander is a straight line) with the limbs of the distribution governing the apex of the bend. As the meander bend grows and becomes more sinuous so the standard deviation of the normal distribution increases.
Bizarrely, a brainbox called von Schelling, who worked all this out, concluded that a river meanders because that's the path that's most probable. Funny that, I always thought they meandered because of erosion and deposition?! Perhaps some things are worth learning about for the sheer fun of it.
