Thursday 17 October 2013

The scientific imperative

My partner runs a nursery school and a couple of years ago they were planning to take the children out on a walk which included a stretch of the old railway line which runs nearby. This route is also very popular with dog walkers, some of whom fail to either notice their dogs taking a dump or choose to ignore it. In a typically gallant way I offered to go out with some plastic bags and clear a 500m stretch of track.

A few days after hing done this the scientific imperative struck. By clearing the track I'd established a baseline and so I found myself, exactly a week later, going out and doing exactly the same job again. The only difference was that this time I wouldn't just put the offending matter straight in the bin but would take it home and weigh it.

But how do you weigh a bag of dog shit? We didn't have any bathroom scales so I couldn't weigh myself with and without the bag and work out the difference. It didn't seem right to use the kitchen scales; partly because they only go up to 3kg and the sample would have to be split, partly out of sheer distaste. Instead I found an old broom handle and located its balancing point. Then armed with a bag of kitchen weights, a tape measure and an understanding of the principle of moments I worked out that the bag of pooh weighed just over 6kg. 

Of course, given that some of the pooh must have been deposited a few days not only would it have lost some of its moisture but also our little helpers, the bacteria, would already have got to work, this is a conservative estimate of the total. We're I to carry out the experiment at shorter intervals, or during winter when the bacteria are less lively and the rate of evaporation would be lower, I might have got an even better estimate but any changes here would likely be swamped by seasonal changes in dog walking practices (there's a phrase for the abstract of the paper if it ever gets published).

All this came to mind because I've just bought our first ever set of bathroom scales. Not to weigh myself of course, but so I could weigh my son's new bike and compare it to the fancy one I inherited from a friend. But now that I've got the scales, all I've got to do next is dig out the one remaining mercury in glass thermometer that I know is somewhere about the house and I can finally do the definitive energy efficiency experiment on my particular method of washing up. 


3 comments:

  1. You need help, Science Man, and I don't mean an assistant... I believe Scientists Anonymous have a 12-step plan that helped free Einstein from his obsession with collecting dust bunnies, and Brian Cox from the belief he was a rock star. They went on to lead perfectly useful lives. I'm told the only problem is that severely-scientistic people insist on repeatedly measuring the length of the steps, and thus never progress beyond Step One...

    Mike

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  2. I'd be more inclined to measure a whole load of steps and then take an average. Luckily I don't often find myself seriously obsessed, though this is probably why my scientific career only made it into the foothills, but I still can't help taking things apart when they break, which is why the toaster now has a wooden handle, or applying the laws of thermodynamics to the clothes on the washing line. But I have to admit to not being in the same league as Brian Cox, who's 12th birthday present was a fuse box, when it actually gets down to doing serious persistent work. A rough idea of what's going on is usually enough, until my attention wanders elsewhere.

    I do, however, have a proprietorial attitude to the old railway line and, in the company of a few other Friends of the Old Railway, could be found a couple of days ago coppicing a stand of willows in order to improve sight-lines and get at the litter hidden within.

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  3. Ah, taking things apart! There I'm with you completely -- I had a success yesterday when I fixed the retracting handle on a trundling suitcase (a simple matter of two rods connected to a button, but still...). A similar flush of bloke-ish triumph to dragging home a plump mammoth, I expect...

    Mike

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