Why do people walk in sleep?Some people unconsciously walk during sleep, perform some work and return to bed. In Science, it is referred as Somnambulism.
We know that we need to sleep when we feel fatigue. There is a sleep centre in the brain which regulates the sleeping of the body. Calcium released to the blood stream due to body activities stimulates the sleep centre of the brain. Then the sleep centre does two things. Firstly it blocks off part of the brain and we enter into ‘brain sleep’. Secondly if blocks off certain nerves in the brain stem and we enter into ‘body sleep’. The combination of the brain sleep and body sleep gives us sound sleep. But under certain conditions these two types of sleeps may be separated. The brain may sleep, while the body is awake. The reason for this is the abnormal activities of the nervous system.
In this condition such people might get out of the bed while the brain is asleep and walk about. This unconscious deed is called Somnambulism.
Why do onions make you cry? Film artistes especially actresses, use glycerin to produce tears in eyes. But you can have ample tears without glycerin if you peel an onion. What is the reason for it?
The answer is simple. The onion has an oil containing sulphur which irritates the eye. The eye has got a special capacity to produce tears when it is irritated. The eye automatically blinks and tears appear to wash the eye and protect it against the irritant. When the sulphur contained in the oil of onion reach the eye the same thing happens and tears roll from your eyes.
Why do we Grow Old?Do you want to grow old? No! Nobody wants to grow old. But even then everyone grows old. There is no medicine even now to prevent ageing. It is a process that begins with birth itself and continues throughout life.
A good number of biological changes take place when we grow old. All the body functions and reactions slow down, strength is lost and the senses become duller. Even weight and height diminishes followed by failure of eye sight, partial deafness, appearance of gray hair and skin with less elasticity.
The reason for these peculiarities is connected with changes taking place in the tissues of the body and body organs. Circulatory system of the body begins to change with age and doesn’t function as actively as it used to. This affects the working of all systems.
The biological changes connected with age cannot be prevented also. It can be slowed down or altered to a certain extent but prevention is impossible. Hence we grow old.
Why do we blink our eyes?You might have seen the wind screen wiper of motor cars. These are highly essential to drive in bad weather. But can you name a built in wind screen wiper the nature has provided to human beings? These are eyelids which move up and down when we blink.
The eyelids are made up of folds of skin. They can be raised and lowered by certain muscles. The eyelids move so quickly that they don’t disturb our vision in any way. We blink our eyes every six seconds, it is estimated. That means we pull them back and forth about 250million times in the course of a life time. It is a protection device of our eyes. The eyelashes attached to the eyelids catch dust which might go into our eyes. When you walk through rain or sandstorm the eyelids automatically drops down and protects our eyes.
The blinking provides automatic lubrication and irrigation of the eyes. The sebaceous glands which are seen along the edge of each lid open between the lashes. Every time the lids close the secretion of these gland come out which lubricates the edge of the eyelid and lashes. Hence always they are wet.
Even though the eyelids are smaller, how much work they are doing? Is’ nt it?
Why is 13th considered unlucky? Nobody really knows the reason behind it. But there are certain theories. One theory is related to Scandinavian mythology. Originally there were twelve demigods. Then later the 13th demigod, Loki appeared. He was evil, cruel and caused human misfortunes. Because he was the 13th, the number 13 considered to be a sign of bad luck.
Another superstition is connected with the Last Supper of Jesus Christ. There were 13 persons at the Last supper and that Judas was the 13th guest. Hence the number 13th came to be a sign of bad luck.
Whatever be the reason, even today the number 13th is considered as unlucky. Even the star hotels avoid the number 13 when they number their rooms. In many hotels after room number12, there is room number 14. It is a wonder that even in this century of scientific development this superstition exists.
