Trees do not grow on mountain tops either because the situation is too exposed, or because the soil is too thin or too frozen to allow their roots to draw nourishment from the ground. In most mountainous areas there is usually a clearly marked timberline, a boundary above which there is no tree growth. Sometimes the height of the timberline …
Read More »Why don’t cranes topple over?
Cranes do not topple over because their jibs or booms are counter balanced at the opposite end from the the lifted load, thus keeping the center of gravity over the base. The first cranes were simply long poles fixed in the ground at an angle, with a pulley at the top through which passed a rope. They were called “cranes” …
Read More »Why don’t Birds on a wire get a shock?
Now how is that possible? The fact is, for a living creature to get a ‘shock’ there has to be a substantial flow of current through the body. However, there is barely any current running through the bird’s body for two reasons. Firstly, the bird not only forms a circuit with the wire, but it also offers a high resistance …
Read More »Why doesn’t distilled water conduct electricity?
Distilled water does — but very little compared to piped, well or salt water. The reason is that the way a liquid conducts electricity is by the positively or negatively charged ions that are actually moving from one of the electrodes to the other, carrying charge (electricity) with them. Salt water has salt in it, NaCl, which readily ionizes or …
Read More »Why doesn’t the sun shine at night?
Well, as a matter of fact the sun is shining at night, but we can’t see it. The Earth, which is rotating in space, turns completely round once every twenty-four hours. In the course of this rotation each part of the glob will be facing the sun for a certain amount of time. It is this time which we call …
Read More »Why doesn’t our stomach get digested?
All the food we eat goes into our stomach. Here, it is broken into smaller and simpler substances and get absorbed into the blood. Then, the blood carries these food particles to the different cells of the body, where they are used to provide energy to our body. How is food broken into smaller particles? When we eat, the glands …
Read More »Why doesn’t one key open every door?
There wouldn’t be much point in locking your door if you knew that anyone cold come along with another key and unlock it! Locks and keys are made for keeping things safe from burglary or damage, and you should always lock up a house if you are going our, or a car if you are leaving it parked in a …
Read More »Why does wood have a grain?
The grain is a piece of wood is the pattern produced by the annual bands or rings which row in the trunk of the tree during its lifetime. The tree’s rate of growth varies with the seasons. In the spring soft porous wood is needed to carry sap. In the summer, stronger cells of hard wood develop to support the …
Read More »Why Does Water stay Cool in ‘Matkas’?
Have you ever had a drink of cool refreshing water from a matka or earthen pot placed outside? Surprisingly enough, the pots are exposed to blazing sunlight, yet the water within stays so cool. How is that possible? This is because of a physical process known as evaporation. When a liquid changes to a gaseous (or vapour) state without boiling, …
Read More »Why are fingerprints of identical twins not alike, whereas that of two clones are supposed to be identical?
Twins are monozygotic dizygotic. Monozygotic twins are externally identical while dizygotic twins may or may not be identical. Every human has two things which are unique to him-finger prints and DNA. In any case twins cannot have identical DNA or finger prints because they are genetically different. But clones are genetically identical and hence finger prints of clones are supposed …
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