uKnoWhy.com » Science http://www.uknowhy.com/blog The fish doesn't think , cause the fish knows everything ! Thu, 20 Oct 2011 22:14:09 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 U know why the “fractals” are called so ? http://www.uknowhy.com/blog/u-know-why-the-fractals-are-called-so/ http://www.uknowhy.com/blog/u-know-why-the-fractals-are-called-so/#comments Tue, 18 Nov 2008 21:27:21 +0000 admin http://www.uknowhy.com/blog/?p=66 The history of fractals in the strict sense is fairly recent. Suddenly opened in 1975 with the revolutionary publication “A Theory of Fractal Sets” of mathematician Benoît Mandelbrot, which became the basis of its fundamental text and manifest.
In “The Fractal Geometry of Nature” Mandelbrot, has coined the term fractal which derives from the Latin word “Fractus” (split), because the size of a fractal is not whole. The fractal geometric figures are characterized by repeated indefinitely until the same reason on an ever smaller scale.
The characteristic of these figures, a feat which derives its name, is that although they may be represented (if you do not claim to represent endless iterations, ie processing for which it retains a special plea geometric) in a conventional two – or three dimensions, their size is not whole. In fact, the length of a fractal “plan” can not be definitively measured, but depends strictly by the number of iterations in which you put the initial figure.
Mathematicians as Waclaw Sierpinski, David Hilber, Georg Cantor and Helge von Koch gave shape to the first fractals, mainly for the pleasure of abstraction, without having the idea of ultimate meaning that would take. Many of them considered these pathological forms, cumbersome or even unpleasant. They would be certainly surprised to learn that today are remembered mainly thanks to those forms that both disgusted them!
Some of these pioneers had good reasons for not appreciating those geometric aberrations. They had indeed realized that Mandelbrot had revealed something that called into question and threatened some of the cornerstones of their discipline. We know now that the era in which these scientists lived (1875 – 1925) was, in fact, a period of crisis for mathematics. Increasingly, the mathematical encounters forms that were unsettling the concepts of space, area, distance and size.
]]> http://www.uknowhy.com/blog/u-know-why-the-fractals-are-called-so/feed/ 0 U know why ‘you take the electrical shock when you get off the car’? http://www.uknowhy.com/blog/u-know-why-you-take-the-electrical-shock-when-you-get-off-the-car/ http://www.uknowhy.com/blog/u-know-why-you-take-the-electrical-shock-when-you-get-off-the-car/#comments Tue, 18 Nov 2008 14:41:25 +0000 admin http://www.uknowhy.com/blog/?p=40

All bodies (the car, the human body and so on.) Have a tendency to lose or to accumulate electric charges through friction or even for a trivial contact (for example, the car is traveling “rubbed” by the wind). When you touch the car, the electricity accumulated on the body passes through the body of the passenger (and the car is “discharged”), from there the electrical shock. This phenomenon is called triboelettricità – electricity through friction – and there is more in dry days. In fact in those days conductivity (the tendency to transmit electric charges) in air, is lower. So when a charge accumulates on a body (eg car) has a tendency to remain there. In a humid day, however, the charges will disperse more easily in the air and you feel a lot less shock touching objects.

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