b'Engineer Innovation | Brownian motionBrownian Motion.The random musings of a Fluid DynamicistHow entropy made my house untidyI am writing this column in a messy room, in a messy house. A house that only hours previously had been (at least to my rather uncritical eye) in a state of almost perfect tidiness, is now in a state of utter disarray. But of course, none of this is my fault. The blame rests squarely with entropy which, as you might vaguely remember from undergraduate thermodynamics, is a measure of disorder in a system (in this case the untidiness of my house). One of the fundamental principles of physics is that the entropy of a closed system always increases over time.While there are an almost infinite number of ways that I could arrange the contents of my house, only a very small number of these billions upon billions of permutations would leave the house in a tidy state. And certainly, none of those involve socks in the kitchen, discarded underwear in the bathroom or cereal bowls in the bedroom. Since there are always many more disorderly variations than orderly one, almost any interaction I have with my home environment will push it towards a state of disorder, and only carefully considered deliberate actions will act against the relentless march of entropy and reduce the amount of disorder in my house. Its a bit like a Rubiks cube. There are 43,252,003,274,489,856,000 different permutations of a Rubiks cube, but only one correctly solved state. Anyone can reduce a solved cube to one of those 43 quintillion unsolved permutations with just a few random twists. But no amount of random twisting will ever return the cube to its solved state. Instead, you have to spend effort and energy first learning how to solve the cube and then correctly applying the algorithms to solve it. Or you could just pull the stickers off and stick them back on like everyone else.Unfortunately for me, the human mind is wired to appreciate order over disorder. Only an artist can turn a selection of paints and a canvas into a beautiful painting. Only a musician can arrange an array of notes into a beautiful song. And only a talented writer can waste time arranging words and letters into an article about entropy when he should be frantically tidying his house. I fear that none of this will be much consolation to my long-suffering other half when she returns home to find her previously tidy house in a state of utter disarray. While I coulduse the Second Law of Thermodynamics as an excuse, experience tells me that it would probably be safer just toblame it on the dog. n66'