You must have seen cows seek out the sand, piled up at a construction site, to lie down and rest. Being stone free is not the only reason why cows prefer the sand. If you have ever stretched out on the beach you would know how very comfortable a bed of sand is!
A little knowledge of weights and pressures will make you understand why sand makes a great bed. And also, why it is more comfortable to sit on a wooden chair than on a flat top, wooden stool, why it is pleasant to be in a hammock even though the pieces of rope that make the hammock are not soft, and why it feels good to sink into a cushion.
When we sit or lie down, our entire weight presses down at the areas of contact of the body with the surface. Hence when less part of the body touches the support, the weight gets distributed over a less area. The pressure at the points of contact becomes more and we feel the discomfort.
That’s what happens when you sit on a flat stool. You press down with your entire weight on a small area. A chair, on the other hand, has a concave seat, so that ‘fits’ the curvature of the bottom, and your weight is now spread over a much greater area, making it more comfortable. On a soft, cushioned, chair, we make depressions on it as per the shape of the body. Pressure is thus distributed widely and evenly, with only a few grams per square centimetre.
And that make the cushioned chair even more comfortable. Like wise, when we (or the cow) lie on the sand, we make an imprint of the body on the sand and so the entire body weight gets most evenly distributed, all over. And that is what makes the experience extremely pleasant!
The same principle works when we pierce something with a needle. It is easy to drive a sharp needle through a piece of cloth but very hard to do the same thing with a blunt nail. Though in both cases the same force is applied, in the case of the sharp needle the force is concentrated at it sharp end, while in a blunt needle it is spread over the larger, blunt, area.
Friday, October 7, 2005
English
for you
