A photo from open sources
A wooden stool is very uncomfortable, because it is so stiff. A the wooden chair is quite comfortable and not at all hard. What is the reason for such a significant difference? In a wicker hammock to lie pretty nice. But the ropes from which it is gossip are very tough. Remember old beds with a metal frame wire? No soft mattresses, but hard to find anything softer like a retro bed. Are there any reasons explaining these contradictions? Lie softly and sit on the hard! It’s small physical miracle. Why a stone bed may seem softer the softest of down feather-beds? Why sit on a simple stool tough, while on a chair, also wooden, not at all hard? Why lie softly in a hammock that is gossipy from pretty solid ropes? Why not lie hard on a wire mesh, arranged in beds to replace spring mattresses? Reason for the post: the seat of the stool is flat, and at the chair it is concave. Human only comes into contact with a stool in a small area. Area the contact with the chair is somewhat larger. And from this it follows that stool presses on the human body less than a stool. Person weight distributed over a larger surface. So, per square a centimeter of the surface has a smaller load. Consequently and the pressure decreases. So, the thing here is more uniform pressure distribution. When we unwind in a soft bed, in it depressions are formed corresponding to the irregularities of our body. Pressure is distributed here over the lower surface of the body rather evenly, so for every square centimeter there is only a few grams. No wonder in these conditions we feel yourself well. The more evenly the pressure is distributed, the more comfortable. Upholstered soft sofa takes the form of bumps the human body. As a result, per square centimeter is just a few grams of pressure. There is nothing strange in soft bed man comfortable. So the point is not at all softness of the starting material. Even from a very hard source material can be built a very comfortable bed. Let’s pretend that someone lay on soft clay that took the form of the body of this person. Then the material was left to dry. In fact, shrinkage clay in the drying process is from five to ten percent. Let’s start from ideal conditions in which shrinkage is absent. Some time will pass and the clay will harden, becoming solid. If the same person lies in a hollow left by him body, he will feel like on a feather bed. In theory, if we assume that the “bed” will be hollowed out of stone, with accurate account of the bumps of this particular person, then such a stone the bed will be very gentle for him personally. Exactly until he will not want to turn around a little, change the position of his arm or leg at least a millimeter. The larger the area that relies on the human body, the softer the bed seems to him, since one a square centimeter of area accounts for less than grams of the weight of this person. More malleable materials are gentle because with incredible ease take the desired shape. And since a person in a toss and turn, changing position, then such materials will comfortable even after he rolled over from side to side. A the clay “bed” would have to be sculpted and dried again. By this its property is soft elastic materials that easily change shape, secured a dominant position in the production of beds, sofas and armchairs. Thus, we were able to establish that tender a stone bed is not a myth, but an indisputable fact, confirmed physicists. Based on “Entertaining Physics” J.I. Perelman
Time
