Pluses and Minuses by Stefan Buijsman

Author:Stefan Buijsman
Language: eng
Format: epub
Publisher: Orion

You can also calculate volume in the same way. That’s a little more difficult because you have to work both vertically and horizontally, but the principle is the same. Sometimes, all you have to do is use the standard formulas I spoke about at the beginning of this chapter. But it might be a more concrete problem: you can also see calculating how dangerous a crash is in terms of calculating an area. The rectangles below the line refer to the movement of the head. The line shows how quickly the head moves, and the higher the line the faster it moves; the sum of all the rectangles shows you how much the head has moved back and forth in total. The idea is the same; it’s just described differently.

Nothing changes more than the weather

At last, the weather forecast for tomorrow is good. But when can you assume that the forecast is right? Weather reports are so often wrong that we should take them with a pinch of salt. At least that’s how it used to be, until large computers made it possible for meteorologists to use calculus to predict the weather. Since then the forecasts have been surprisingly accurate compared, for example, to those of the 1970s.

Until then, the weather was predicted using three simple steps. You looked out of the window and studied the clouds, temperature, and so on; then you searched in the records for an earlier day on which the weather was similar; thirdly, you used the weather on the following day back then to forecast what the weather would be the day after in the present. In other words, you assumed that the weather would be exactly the same as it was before, with the coming few days the same as they were then. If you only look at clouds and temperature, that is of course hardly ever right. Predictions in the past were very often wrong because the weather is a little more complicated than that.

Of course, it’s also possible to ‘calculate’ the weather. The changeability of the weather caused by air flows is a perfect application for calculus. In the First World War, for example, the English mathematician Lewis Richardson experimented with using maths to forecast the weather. He started cautiously by trying to forecast the weather for the coming six hours. He would look outside, do a quick calculation and then know what the weather was going to be like six hours later. Richardson was, however, wrong about the ‘quick calculation’: it took him six weeks!

Forecasting the weather by calculation was therefore very difficult. It not only took far too long, it was often wrong as well. That’s because, with the weather, so many things change. The air is constantly moving and temperature, humidity, etc. are consistently changing. You have to know where areas of high and low pressure are and how they are moving – and for a very large section of the atmosphere. Even small changes can make a significant difference.

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