The Rainbow Formed

How is the rainbow formed?
            We observed the sky on a rainy day, and seen the arc of multi-colored lights that appears when the sun shines through the rain.

            Though it appears to be white, light actually comprises seven different colors. They are--- Violet, Indigo, Blue, Green, Yellow, Orange and Red, abbreviated as VIBGYOR. Each letter of this word represents a colors is known as dispersion, while the strip of seven different colors is called the spectrum.
White light on refraction, splits into seven colors
            A rainbow is normally seen after rain, when the atmosphere is full of small droplets of water. These spherical raindrops act like tiny prisms. When the rays of the sun fail on these droplets, the rays get refracted as they pass through the raindrops, and split up into the VIBGYOR colors. Each component of the ray of light gets refracted at a different of the ray of light gets refracted at a different angle, thus separating into seven different colors. Thus, white light is actually made of seven colors.

            The rainbow is a semi-circular arc because the sun is circulating. A complete rainbow has a primary and secondary arc. The primary arc is more brilliant and its colors are violet on the inner side, then indigo, blue, green, yellow, orange and red on the outside. The colors are reversed in the secondary arc; red is on the inner side and violet on the outer side. The secondary are is located above the primary arc. This rainbow is formed by sun’s rays, which have been reflected and refracted again after the first reflection and refraction within the raindrops.

            The rainbow is seen in that portion of the sky that is opposite to the sun. It is essential for the formation of the rainbow that the sun shines just after the rain. It is also necessary that the sun, our eyes and the centre of the rainbow lie on the same plane. Rainbows are generally seen in the early morning or late evening, after the showers.


What is hypnotism?
            Hypnotism is an art, which can affect the mental state of human beings. The hypnotized person acts according to the directions given by the hypnotist. Man has been practicing hypnotism from ancient times to demonstrate supernatural powers, magic and miracles. Franz A. Mesmer, a doctor from Vienna, was the first person to begin a scientific study of hypnotism. For a long time, it was known as ‘mesmerism’ after the name of the doctor. It was James Braid, a surgeon from Scotland, who used the word hypnotism for the first time in 1840. This word was originated form the Greek word ‘Hypnos’ means ‘state of sleep’.
hypnotized person can be directed to do anything be a hypnotist
            In fact, a hypnotized person appears to be dozing. His brain is in total control of the hypnotist, and he can be directed to do anything according to the instructions given by the hypnotist. Hypnotic power should be used only over those persons who are fully willing and ready to cooperate. No body can be hypnotized against his wishes. The person to be hypnotized is usually asked to sit in a dark room. The hypnotist then repeatedly tells his subject in a very calm voice to relax and sit comfortably.

            Thereafter the subject is asked to concentrate his attention and focus his eyes on some object. When he gazes at that object for a long time, his eyes start getting tired. When this happens, he is asked to close his eyes. The subject is in a state of sleep thereafter. He is at the command of the hypnotist and does whatever he is directed to do.

            A hypnotist can make a person experience himself as blind, deaf or dumb, and even make him shiver. A person under the influence of hypnotism can be made to do things that he would never do in his normal state. When he regains his normal state, he does not remember what he did in the hypnotized state.

            Hypnotism is also used to operate on patients without anesthesia and also help people deal with mental anxieties.

            A person can also induce hypnosis himself; this is called self hypnosis or autohypnosis. Hypnosis is not a game. It can be dangerous when performed by an untrained person.

Dust Useful to Us

How is dust useful to us?
            Many of us believe that dust is harmful to us but this is only one side of the picture.

            Dust is also useful to us. But before we go through the uses of dust, let us find out what dust is, and how it is formed. Every solid substance is composed of very small particles. When a substance disintegrates, its small particles scatter and they form dust particles.

            For example, if we break a brick into small pieces, it produces small particles in the form of dust. There is a number of ways b which dust is formed. Smoke generated by the burning of coal, wood, petrol, etc. also produces dust. Dead plant and animal matter, sea salt, desert sand, volcanic ash, etc also produce dust particles. These dust particles mix with air, which are carried from one place to another.
Dust particles helps in rainfall
            Thus, particles form the Earth’s surface fly in the air in the form of dust. Did you know that dust helps in rainfall? The water vapor in the clouds condenses on dust particles in the form of water drops. These drops fall to the Earth as rain. The absence of dust particles can hinder rainfall. Like wise, mist, fog, etc. are also formed due to the presence of dust particles in the atmosphere.

            The dust present in the atmosphere scatters sunlight in all possible directions. It is due to this phenomenon that there is light even after sunset for an hour or two. The lovely red color seen at sunrise and sunset is also the result of the dust particles and water vapor present in air.

            We are able to witness the breath taking hues of the sun seen during twilight owing to the scattering of light by dust. Thus the dust particles, which are usually considered harmful by many, are actually indispensable.

Ice Float on Water

Why does ice float on water?
            We may have often put ice cubes into a glass of cold drink, but have we ever wondered. Ice floats on water because it is lighter than that. Long ago, a Greek scientist named Archimedes also wondered about it. He hit upon a solution, which is today, known as the Archimedes principle. He put forward the law of flotation of bodies. According to this law, whenever a body is placed in water, two forces act upon it—the weight of the body acting downwards and the buoyant force of water acting upwards. If the upward thrust of water, the body floats. In simple words, a lighter object always floats on water. On the other hand, if the weight of a body is more than the weight of the water displaced by it, it sinks. This phenomenon is same as a piece of word floating on the surface of water. Since the weight of wood is nearly half the weight of an equal volume of water, half of the wood remains submerged, while the other half can be seen on the top. Generally, when a liquid changes into a solid, its molecules come closer to each other and it contracts. As a result, the volume of the liquid decreases and its density increases. Hence a substance becomes heavier in solid state than in the liquid state.
Ice floats because it is slightly lighter than water
            Water is a peculiar liquid. When it freezes and changes into ice, its molecules—instead of coming closer-expand. Thus, the volume of ice increases. As a result of this expansion, its density decreases to nine-tenths of the density of water. So if you try freezing nine liters of water, you will get ten liters of ice!
Submerged Iceberg
            The ice cubes floating in your drink are very much similar to the icebergs floating in the sea. This also explains the reason why the maximum portion of the giant icebergs remains submerged in water while only a tip (1/10 part) is above water.

            In the olden days, a number of ships sank, including the Titanic (sank of April 15, 1912), as they could not see the icebergs submerged in water. This is why icebergs are considered to be dangerous. The ice under water (9/10 of the whole) displaces water. The weight of the water displace equals the weight of the ice. The largest iceberg in 1956 was in the South Pacific. It was 335 kilometers long and 97 kilometers wide.


What is consciousness?
The word consciousness in psychological terms refers to the condition of alertness of the organism. The brain is the control centre of the nervous system of the body and plays a major role in mans thinking remembering and alertness. Unconsciousness refers to the state of sleeping. Between these two conditions one may have varying degrees of consciousness.
            In a condition of full consciousness the level of alertness is high. For example if someone is playing chess and wants to win he would try to remain in a state of high alertness and deep concentration. Similarly the circus gymnasts would have to be very alert during their performances.

            If a person is dozing he is said to be in a state of lower level of consciouscious if he falls asleep.

            These are different states of consciousness that we come across in our normal day to day life. However unconsciousness or sub consciousness can also be produced by artificial means. A high state of consciousness’ can be produced with the help of some medicines which act as a stimulant and make a person more active beyond his normal ability. Such medicines affect the central nervous system and produce abnormal conditions. Caffeine in a strong coffee or tea can act a powerful stimulant for some people. Too much alcohol can produce drowsy effect and finally unconsciousness’.

            Certain diseases have a marked impact on the level of consciousness. There are some mental diseases that can lower the consciousness of a person. Emotional disturbances also affect the state of alertness of an individual. Highly emotional people often girt the felling of depression.

            Today scientists have developed several medicines and shock therapies that can contra the level of consciousness. These methods are used for treating people with lower level of consciousness how ever these should be used only when prescribed by a physician.

Our Body Stops Growing

Why does our body stop growing after a certain age?
            All living beings grow. The process of growth is a natural way of life. Plants, animals, birds, and human beings all start growing up just after the conception. In the first nine months, the foetus develops in the mother’s womb and keeps on growing after birth also. When a child is born, he is about 50 centimeters high. And in the next 20 years his height becomes more than triple. Mans growth stops after the age of 20-22 years.
Growth almost stops by the late teenage
            In its simplest sense, growing means adding living matter to the matter, which is already present in the body. In fact, these are mainly proteins that help the body to grow. We get these proteins from meat, fish, eggs, seeds, vegetables, fruits, milk and its products. During the process of digestion, these proteins get converted into amino acids. These amino acids produce cells and tissues.

            The endocrine glands, which secure hormones correctly into the bloodstream, control our body growth. These glands are the thyroid hand and some sex glands. The pituitary gland controls the grower of bones. When a child is born, his thymus glands are very large but it starts shrinking after the age of 13-14 years. The body attains full maturity by the age of 20-22 years and after that the growth stops. The glands responsible for the physics growth become less active after this age. After 40 years of age the body states contracting the drying up of the cartilages in our joints and spinal column.

Left Handed People

Why are some people left handed?
Most of the people in the world do most of their work with the help of their right hands; but 4% of the world population is left handed. If we go through the history of mankind we find that many of the great men of the world have left handed. The world famous sculptors Leonardo Ad Vinci and Michelangelo both were left handed. Parents of the left handed children usually feel worried about this habit and make efforts to correct it. But psychologists believe that if a child is a left handed he should not be forced to hanger this habit.
People whose right hemisphere of the brain is dominant are left-handers
            If we examine the constitution of the body carefully we will notice that our body is not fully symmetrical. There is a little asymmetry between the left and right side of the body. Generally right side of the body id lightly heavier than the left parts. Even the functions of these parts are somewhat different. Usually the left half of the brain is predominant over the right half. In such cases, the nerves from the brain cross over at the level of the neck and go to the right side of the body. Such persons are right handed. Most people of the world fall under this category. But there are cases where right half of the brain is predominant over the left, nerves coming our of the brain pass on to the left parts of the body. Such people perform all their functions with their left hands. That is why some children write and even eat food with left hand.

            Have you wondered why left hander’s are in such a minority in comparison to the right hander’s? Scientists have not been able to solve this riddle till now. Since the number of right hander’s is so large, the door handles, locks, screwdrivers, and motorcars, musical instruments all are designed keeping in view the convenience of the right hander’s. Even buttons are fixed on the right side for the same reason. The left handed people experience some difficulty in handling all these but get used to the functions with a little effort.

The Human Digestive System

How do we digest food?
            The human body requires a constant supply of food in order to carry out its numerous activities. The food we consume performs two main functions in our body. First, it supplies proteins for the growth of the body and second, it supplies energy to the tissues for the day to day work.
The Human Digestive System
            The process of digestion is very complex and elaborate. Digestion begins at the mouth. When we chew food, the saliva produced in the mouth moistens it. The saliva contains a substance called ptyalin, which converts the starch of the food into simple sugar. This is the first stage of digestion. Therefore we should swallow the food only after chewing it properly.

            After that, the food material passes through the esophagus to the stomach where the gastric juices get mixed with it. The walls of the stomach secret juices containing an enzyme called pepsin and hydrochloric acid. Pepsin breaks down the molecules of proteins into peptones.

            From stomach, the food then enters the small intestine, where it mixes with three other digestive juices- bile, pancreatic juice and intestinal juice. The liver produces bile. Its main function is to digest the fats. The pancreatic juice is basic in nature and neutralizes the acids. It also digests the proteins. The intestinal juice converts sugar into glucose. Here, many enzymes also mix with the food. The digestion of food mainly takes place here. The digested food is them absorbed by the blood vessels present in the wall of small intestine. The remaining waste of the food now goes to the large intestine and is finally excreted out of the body as faeces through the anus.

Intoxicants Affect Our Body

How do intoxicants affect our body?
            Alcohol, wine, cigarettes, bidi, opium, intoxicating hemp ganja and bhang, cocaine or morphine etc. are known as intoxicants. Many people indulge in them for various reasons but they have a number of harmful effects on our health. The uses of these are also considered a social evil.

            People generally consume tobacco in the form of bidi, cigarettes or Hubble bubble hookah. Some people chew it raw. Tobacco contains a powerful poison called nicotine and 26 other poisons. Even though it is contained in extremely minute quantities, they harm our body to great extent. When we smoke, our blood absorbs some of the nicotine. This nicotine excites our nose and throat. This also causes coughing. Smoking increases blood pressure. It accelerates the heartbeat and cases heart ailments. It also affects the body temperature and blood circulation. Recent scientific researches have shown that smoking causes lung cancer too. It has also been proved that smoking shortens the lifespan of people. Moreover, indigestion, peptic ulcer and cancer of the mouth are also among its after effects. What is worse is that nicotine is an addictive substance and those who are used to it find it impossible to give up smoking.

            Use of alcohol in the form of liquor is also very harmful for our heath. Some people carry the wrong impression that drinking makes the body more active. But this is far form the truth. All the physical process gets slowed down when one consumes alcohol. More liquor like whisky, rum or brandy contains a high degree of alcohol. The alcohol has unsuitable effects on our body. As soon as it enters our body and mixes with the blood, it immediately starts influencing some areas of the brain. As a result of this, the individual starts getting intoxicated. His vision gets disturbed. And his thoughts become illogical and he finally becomes senseless.

            Accidents caused by drunken people are very common these days. Statistics show that one cut of every five accidents is caused by people who are drunk. Drinking also reduces the control over muscles. Prolonged drinking causes dangerous diseases of the liver.

            Some people take many types of pills of relieve themselves of pains and mental tensions. These are very dangerous for health. Excessive use of these weakens the memory. Once you develop the habit of taking intoxicants, it becomes very difficult to get ride of them. The use of LSD, brown sugar, opium, ganja, and charas is certainly an invitation to death. These substances adversely affect the body and brain and give birth to crimes in the society. We should, therefore, always avoid using them.

            To deal with these problems many reform organizations have established to treat the patients.

The Blood Group Varies from Person to Person

Why does the blood group vary from person to person?
            Even though the blood of all the human beings looks alike, in reality, it is not so. Our blood is mainly composed of red blood corpuscles, white blood corpuscles, platelets and plasma. It has been observed from microscopic investigations that molecules of antigens found on the surface of red blood corpuscles are different in different people. Antigen molecules are a kind of proteins that stimulate the production of antibodies. It is this difference in the antigen molecules that gives rise to different groups of blood.
Blood Compatibility
            In the year 1900 Dr Karl Landsteiner discovered two kinds of antigen- A and B type. He was awarded the Nobel Prize for medicine in 1930 for this discovery. Blood containing A type antigen was classified as A group, while that containing B type as B group. Subsequently, it was discovered that the blood of some people contains both A and B type antigens. This type was classified as AB group. The blood that contained neither A nor B type antigens was called O group. Thus the blood of all human beings has been divided into four groups. Studies made till now have revealed the existence of more than 200 groups of human blood.

            However, as far as the transfusion of blood of nay patient is concerned, only the aforesaid four groups of blood are important. Before transfusing blood to any patient, it is essential to get his blood group tested. It is very essential to match the blood of the patient with that of the donor before transfusion. It has been found that the blood of even real brothers and sisters may not be of the same group. On the other hand, the blood of two individuals belonging to two different states may be of the same group.

            If the wrong blood is transfused to patient, he can die, because antigens of different classes cannot combine with each other. However, blood plasma of one individual can be given to another because it is the same in every body.

            Landsteiner and Alexander S. wiener discovered another important blood antigen in 1940. This additional factor is called the rhesus antigen or Rh factor.

            Rhesus antibodies do not occur in naturally blood groups- both for
recipients and donors. AB groups are called the universal recipients whereas O is the universal donor.

Some People Snore during Sleep

Why do some people snore during sleep?
            We must have definitely come across people who snore during sleep. Their mouth remains open and a peculiar sound comes out while breathing.
A woman snoring during the sleep
            Normally, people breathe through nose. But some peoples nose remains blocked due to some reason. And thus they breathe also make a person snore. When we are asleep and breathe through the mouth, the air coming out caused our soft palate tissue at the back and top of our mouth to flutter back and forth. Thus, a strange sound of snoring is produced. Often this vibration also caused cheeks, lips and nostrils to vibrate which produces an even louder sound. When we are awake, the palate remains tight and, therefore, no such sound is produced.

            If we clean our nose and mouth before sleeping, snoring can be controlled to some extent. This increases the possibility of breathing through nose rather than through mouth. If one develops the habit of breathing through nose, the possibility of snoring is greatly reduced.

            Breathing through mouth is harmful for heath. The germs of many diseases can enter directly into the mouth and cause diseases. If we breathe through nose, the hairs present in the nose do not allow these germs to enter into the body. It is, therefore, advisable to develop the habit of breathing through the nose.

Human Body Temperature

How is our body temperature maintained?
            Man is a homoeothermic or warm blooded creature. His normal body temperature remains almost constant in all the seasons. The temperature of the surroundings affects it very little. The normal temperature of a healthy person remains at 370 F or 98.40 F. as a result of this, the body remains warm.
Human Body normal temperature remains at 37 centigrade degrees
            Our body receives heat energy from the food we eat. The food substances produced heat by the process known as oxidation. Oxidation is a kind of combustion that takes place in our body. We know that the burning of fuels produces heat. The oxidation of food produces heat in the similar manner. The only difference is that burning of fuels produces both heat and light, while combustion of food produces only heat.

            The body uses the heat produced by food for doing different kinds of work. Food such as flour, rice, sugar and potatoes contain sufficient quantity of carbohydrates. To consume foods containing carbohydrates is very important and necessary to the body because they keep body warm and provide it energy. Normally 2500 calories of heat energy is produced every day in the body of a human being. This energy keeps the body warm and enables its various organs to do different kinds of works.

            The temperature center of the brain maintains the temperature of the body. This center consists of three parts- control center that regulates the temperature of the blood; heating center that raises the temperature of the blood when it drops; and the cooling center that cools the blood when the temperature rises.

            Whenever a disturbance occurs in the temperature center of the brain, the body starts shivering and these results in fever. If the disturbance occurs in the beating center it causes shivering whereas the abnormality in the cooling center causes fever in the body. The body always radiates heat to the surroundings. Whenever we sleep or sit on something, it becomes warm due to the heat coming out from our body.

            Many diseases cause a rise in body temperature. This happens because the body produces more heat than it can give off. Much disease causing bacteria are killed by even a small increase in the person’s body temperature. But if the body temperature rises above 440 C, it often results in death because some important enzymes are destroyed.

Female Mammals Produce Milk

How do female mammals produce milk?
            Mammals are those living beings whose females produce milk to suckle their young. They are warm-blooded and have well developed brains. They gibe birth to young ones and feed them with their own milk. Mammals breathe through lungs and their bodies are covered with hair.
Internal Structure of Mammary Glands
            Milk in the female’s mammals is produced by mammary glands that are located in the breasts. They are bag shaped and big in size. Shortly before the birth of her young hormonal changes in the mothers result in increased development of the mammary glands. They produce large drops of fats which when mixed with fluids present in the breasts become milk. Corpus luteum of the ovary also produces a hormone that helps in the process of milk production. Most of female mammals have tears or nipples form which the young can suck milk.

            At present, there are about 4400 living species of mammals grouped into 19 orders and about 120 families. They of course, differ from one another in their bodies, shapes, sizes and habits. Most of them live on land but some live in water and air also. For example, whales and the dolphins are mammals, which live in water. And, the bat is a mammal that flies in the air. They exist in different climatic conditions- hot, cold, dry or humid. Most mammals give birth to less than 10 young ones a year. Humans usually give birth to only one baby at a time. Apart from human beings, cow, buffalo, sheep, goat, etc. also come under the category of mammals.

Our Ears detect Sound

How do the ears detect sound?
We hear a number of sounds every day. Some are pleasant while others are not. On the basis of its structure the human ear can be divided into there parts external, middle and internal. Anything producing sound first vibrates. These vibrations set up a motion of sound waves in the medium through which the sound reaches our ear. The external ear has large surface and can receive a number of sound waves at the same time.
The internal structure of human ear
            When the sound waves hit the external ear, they are transmitted to the middle ear through a pipe. The middle part has the ear drum, which starts vibrating when tenses sound waves hit it. Just behind the ear drum there are three small bones called hummer anvil and stirrup. As the ear drum vibrates, these bones also start vibrating. These vibrating are then transmitted to the cochlea. Which acts like a spring it is surrounded by a fluid the fluid contains the nerve ending.

Due to the vibrations of cochlea the fluid also starts vibrating and this activates the nerve endings. The activation of the nerve ending produce impulse which are taken to the brain the auditory nerve and we hear the sound.

            Our ears can detect both feeble and intense sounds with frequencies ranging from 20 Hz to 20,000 Hz. In the order to keep the ear healthy, it is essential to produced in the ear, which gets deposited on the ear drum if it is not cleaned. If this wax accumulates then it can lead of our ears and consult the ENT expert as soon as there is trouble in the ears.

We get Tired

Why do we get tired?
            Most of us feel tried after working all day long. We also feel tried after running, swimming or exercising.

            When we work at a fast speed, our muscles do not get as much oxygen as they need. The glycogen stored in our muscles is transformed into lactic acid through the process of fermentation provide extra energy to the body. The lactic acid reduces the working capacity of the muscles. This state of the body is known as muscle fatigue.
Tired woman
            The lactic acid acts as a poison for the muscles. If we can expel the lactic acid form the muscles by some process, they can again become fit for working.

            As a result of the muscular action, some other substances called fatigue toxins are also produced in the body. These acids and toxins are circulated through the body by the blood, because of which both the body and the brain get tried. Even when we do some mental work, lactic acid and fatigue toxins are produced in the body and we get tired. Scientists have conducted many experiments in this field. A dog was made to work hard. And when it got tired and went to sleep, its blood was transferred into an active dog’s body.

            Guess what happened!

            The active dog also became tired and fell asleep. Similarly, if the blood of an active dog is transfused into the body of a tired dog, it immediately becomes active.

            Fatigue is not only chemical process but is a biological process also. It is a defense mechanism. This warns us to stop working and give test to the body. Fatigue cannot be removed quickly. It is essential to gibe rest to the cells of the body to overcome remove fatigue. It repairs the damaged cells of the body.

            When the body receives proper quantity of oxygen through berating the lactic acid is converted into glycogen and we feel energetic once again. Little rest also removes fatigue is supplied to some extent by our food also. That is why a tired person feels very hungry.

We Hiccup

Why do we hiccup?

            Sometimes you begin to hiccup and they just do not seem to stop, no matter how much you try. At such times, your grandmother might tell you that someone is remembering you. Some people even say that the person who is hiccupping has secretly eaten something. All these sayings are mere myths. Hiccups are just reflex actions by which the body protects itself.
Movement in diaphragm when we hiccup
            Hiccups are short, sharp, and very sudden breaths of air which happen when our breathing muscles jerk, making us gasp. There is a diaphragm located between the chest and the stomach. While inhaling air this diaphragm does down presses the stomach due to which the lungs are filled with air; while exhaling air, when the diaphragm goes up, the air  comes out from the lungs. Thus the diaphragm goes up and down and the process of respiration continues incessantly without making any sound. The diaphragm functions like a piston.

            Sometimes, due to the formation of gas or increase of acidity in the stomach, the diaphragm gets irritated and as a result contracts suddenly. In such a situation, the air passing into the lungs experiences obstruction and makes a peculiar sound. This is known as a hiccup. It is simply a process by which the body tries to expel gas or undesirable food material out of the stomach so that respiration remains unobstructed. Shrinking of the diaphragm due to drinking or the growth of a tumor near it also causes hiccup. Hiccups can be cased by eating or drinking too much or too fast. It may also be an indication of material disorders and brain-stem disease.

            Hiccups usually last for a few minutes and disappear if nothing is done about them. The best way to stop a hiccup is to drink a glass of cold water because the cold water stops the irritation produced in the diaphragm and it resumes its normal movements. Holding breath for a while can also stop hiccups. Sometimes the hiccup stops when one sees something frightening. If the hiccup does not stop even after a long time, it is advisable to consult a physician. Generally, in such situation, doctors prescribe the inhaling of oxygen mixed with 5%- 10% carbon dioxide. Chlorpromazine also suppresses hiccup.

Fuel of our Body

Which substance work as fuel in our body?

Just as an engine needs, fuels like coal, petrol diesel, etc. to run similarly our body also requires fuel which provides us the energy to work with. The substances, which act as fuel or energy for our body, are fats and carbohydrates. The food we consume is burnt with the help of oxygen that we obtain fro breasting and produces these constituents. The energy, which is released in the process, is used to perform all our voluntary protein is required for growth and tissue repair while vitamins and the minerals are necessary for the proper functioning of various body organs.
Nutritious Food
            Just as a machine needs pepper fuel, our body requires nutrients to keep it in proper working condition. The nutrients come from the food we consume. Our body absorbs and utilizes the useful elements form the food we eat, and rejects those that are not needed in the form of waster material. We excrete about 2 kilograms of urine and stools daily. We inhale oxygen when we breathe and carbon dioxide is produced as a waste material. About 400 gram of water is excreted through the process of sweating.

            Human body temperature remains constant between 980 F and 990 F.  There is a wonderful equilibrium between the production and consumption of heat in the body so that the body temperature remains constant. Food is measured in units of energy, called calories.

            Our body is a wonderful machine that works continuously without any break. Even when we are in sleep, many processes such as respiration, digestion, heart beating, etc. go on incessantly. These processes also consume fuel continuously. Eating a balanced and nutritious diet provides the body wit all its energy requirements.


What is cholesterol?
These days everyone talks about harmful is cholesterol and how important it is to eat a diet with less of this element. What exactly is cholesterol?
            Cholesterol is an organic compound belonging to the steroid family. Occurring either in a free state of as esters of fatty acid in practically all animal tissues. The molecular formula for cholesterol is C27 H46 O in a normal man it is about 0.3% of his average weight. It is the starting material from which the body produces bile acids asteroid hormones and pro-vitamin substance in the body. Our body also uses it to help the digestive system.

            Cholesterol was discovered in 1812. Its name arises from its occurrences in gallstones derived from the Greek. Word Chole-stereos-ol meaning bile-solid. The synthesis of cholesterol occurs in various tissues and organs particularly the brain liver and arteries.

            The increase in its quantity beyond certain level can be harmful for our body. Execs of fats and cholesterol get deposited in the walls of arteries causing blockage and hardness thus obstructing the free flow of blood. This may lead to heart problems. When the arteries get blocked the quantity of blood flowing in them decreases and as a result the oxygen supply to vital parts of our body is also decreased. This condition is medically termed as arteriosclerosis.

            High cholesterol deposits may be trap small blood clots that would normally pass through blood vessels.

            We knew that coronary arteries play a vital role for the proper heart function. They provided oxygen and carry blood to the heart. If a coronary artery gets blocked that particular part of the heart may stop functioning leading o a major heart attack which can even prove fatal.

            Cholesterol in blood can be controlled by a regulated diet. A high concentration of cholesterol is present in the foods of animal’s origin like meat, egg, butter, etc. doctors advise to avoid high cholesterol food by substituting them with unsaturated foods. Like fruits, vegetables, reveals and so on. 

            Lowering cholesterol levels in the blood can help to reduce the risk of heart attacks. There are many other measures that can be taken to maintain the desirable cholesterol level. This includes giving up smoking regular exercises, and avoidance of overeating and fatty substance.

Human Muscles Work

How do our muscles work?
Whether we are running waking lifting an object or just getting up from a couch, a number of muscles come into play. There are about 639 muscles of all shapes and sizes in the different parts of our body. A medium sized muscles of the body 10 million cells. All the muscles of the body put together have almost 6,000 millions cells. Each of these muscle cells is like a motor. Containing ten cylinders arranged in a row. The cylinders are tiny boxes that fountain fluid. A muscle contracts when the brain sends a message to these tiny boxes. For a fraction of second the fluid in the tiny box congeals and then returns to normal. It is this action that causes the muscles to move. Muscles make up to about 40% weight of the body.
Human Muscles Movements
            From birth to death, these muscles form a very important part of our life. They produce heat and help in the movement of food from one place to another in the digestive system. They take the air to the lunges. If they stop working all the factions of our body would come of halt. The throbbing of the heart and the expansion and contraction of intestines would also stop.

            The muscles of our body are of three kinds striated of voluntary smooth or involuntary and cardiac. Most of the muscles of the hands legs neck and head are voluntary because al these limbs function according to our wishes. Most of them are attached to nuns and are called skeletal muscles. Striated mussels are made up of many fibers. Smooth or involuntary muscles are those which functions on their functioning. The muscles of the stomach and intestine are involuntary because the process of digestion contours on ties own. These muscles help in blood circulation. The cardiac muscles are found in the heart. They are also involuntary muscles. They cannot be controlled by our will. It is most important muscle and is fibrous in structure. With the help of his muscle the heart beats 2,500 millions times in a life span of 70 days.

            Several body parts such as brain, spinal cord and nerves are involved in the working of muscles. A muscle is made up to of many tiny fibers that contract when they receive a signal from the nerve. Muscles fibers either only a few of its fibers contract the muscles contracts more powerfully when more of its fibers contract. All muscles work by contraction.

Intake of Salt helps our Body

How does the intake of salt help our body?
The human body contains about 65% of water. Some body parts have very high water contains for instance muscles contain 75% water while liver 70% content. The water present in the body has common salt dissolved in it. To body we eat salt. Now the question rises why should we maintain a certain level of salt in our body?
Salt is an essential component in our body
            According to one scientific theory, all land animals including man, are the descendants of organisms that came from the sea. The body fluid of this creature had a high content of seawater. Since they ware born in the seas, they were not able to survive without salt water. When these creatures shifted to dry land, they retained of the body were accustomed to it. Once as there could not get it from the sea, to make up to deficiency of salt, they started consuming salt.

            Carnivorous animals do not need extra salt, since their salt requirement is fulfilled by the amount of salt present in the meat they consume. This is true of human beings also. Non vegetarians need only small quantities of salt. Eskimos who are mainly non vegetarians take very little salt.

            Those who live on land need more salt. In the ancient Mexico, common salt was treated so precious that people used to worship it as god. The word salary comes from the word salt because in roman time’s solarium of allowance of money for salt was given to officers and men in the roman army. Most of the salt in our body is stored in the skin. The excretions from our body deplore the amount of salt in our body. If we consume food without salt, the amount of salt the amount of salt in the blood reduces in which case the salt stored in the skin gets used up. The body is mainly done by the kidneys and skin as sweat.

            Salt is essential for effective functioning of our body. Today iodized salt is consumed to meet the iodine requirement in our body. Iodine deficiency cause ailments like goiter and congenital disease like cretinism. Some medical authorities opine that excess of salt intake increases the risk of high blood pressure and hence leads to hear attack.

Cutting of Nails and Hair Painless

Why is cutting of nails and hair painless?
            You may have noticed that whenever any part of our body is cut, we experience tremendous pain but when we cut out hair or nails, we do not feel any pain.
Nails are made by dead cells
            We have, in all, twenty nails in our hands and feet. We do not experience any pain in cutting them because they are composed of dead cells. Nails are special structures of the body formed form the outer layer of the skin. They are made up of a hard material called keratin. Keratin is a kind of dead protein. The base of the nails is located inside the skin of the fingers. The skin beneath the nails is similar to that in other parts of the body, but it has flexible fibers. These fibers are attached to the nails and keep them in a fixed position. Generally nails are thick but their roots inside the skin are very thin. The portion near their roots is white and semi circular. It is known as lunule. The fingernails grow at the rate of about 2 inches per year.

            Nails are very useful for our body. They help us in picking up things as well as in doing artistic work. They protect the fingertips too. For ladies, nails are an object of beauty.

            Similarly, hair is also a filamentous structure made of keratin- a dead protein. The hair grows on our head about 13 millimeters each month. We have about 100,000 hairs on our head. The base of the hair- the root, as it is often called is in the form of a round bulb. About 50 to 100 hairs fall every day. Each hair usually lasts for about 3 years and then it falls. New hairs grow to replace the fallen ones. They grow out of pits in the skin and are called foliates. And, it is the shape of these follicles that makes our hair straight, wavy or curly.

            Men and women from very ancient times have practiced the custom of cutting and styling the hair. Hairdressing occupies a very important position in grooming and beautification in present time.

Nose Detect Smell

How does the nose detect smell?
            The nose is an indispensable organ that is used for breathing and sense of smell. If it is not working properly, we cannot distinguish between foul smell and fragrance. How the nose detects smell?
The Internal Structure of Human Nose
            The nose may look like a very simple structure but it is very complicated in nature. The nose is composed of two bones and is situated between the yes below the head and above the lips. These two bones from a kind of bridge. In between them lies a wall of cartilage. Which divides the nose into two parts called the nasal cavities. At the end of the nasal cavities lies a thin membrane called the mucous membrane, which secretes a special fluid. This fluid keeps the nose moist. The hair inside the nose waves back and forth to prevent dust particles, bacteria and fluids from entering the lungs. So the air that goes into the lungs through the trachea has already been filtered by the nose.

            The smell is detected by the cells present in the two olfactory nerves situated at the end of the nasal cavities. These cells are called receptors and are embedded in the mucous membrane. They are spread over an area of 250 square millimeters.

            It is believed that the sense of smell is closely related to that of taste. We know that if a man has blindfolded and his nose was blocked, he would not be able to differentiate the taste between a potato and an apple?

Twins Born

How are twins born?
            You may have come across twins. Have you ever wondered how two babies are born at the same time? Normally a woman delivers only one child at a time. This child can either be a male or a female. Sometimes, however, two or more children are born at a time. Two children born of the same mother at one time are known as twins. Do you know how twins are born?

            Between the 10th and the 18th day from the onset of menstruation, the reproductive organs of the female produce an egg called ovum. If during this period the female mates with a male, one of the male sperms fuses with the ovum. This union of the ovum and sperm is known as fertilization and the female is said to have become pregnant. 280 days later, the woman gives birth to a child.

            But sometimes after the conception, the ovum divides itself into two parts. Both these parts develop in the womb separately as two embryos. As a result, two babies are born simultaneously. The two children so produced are similar in complexion and appearance. Most of their traits are similar. Both the children will always be either boy is girls. This is because they are produced from the same ovum. Such twins are called identical twins.

            Sometimes the twins may not be similar. They could also belong to different sex. How is that possible? This is possible when two sperms form the male semen enter separately into two ova of the same female. The two ova then develop into two different babies. The children so produced may be different from one another. They may or may not be from the same sex. Their characteristics may also differ. Such twins are called non-identical or fraternal twins.

            Sometimes we come cross the term Siamese twins. The term Siamese for conjoined twin is derived form the famous celebrated twins, change and Eng-Bunker born in Mekong, Siam (now Thailand) in 1811. They were joined by a cartilaginous band at the chest. Both of them died with in a gap of three hours at the age of 62 in 1874. However, such twins are very rare.

            Some women have given birth to more than two children at a time. On April 22, 1946, a woman in Brazil gave birth to ten children at a time- 2 boys and 8 girls. Spain and China also hold record of having women who gave birth to 10 children at a time. On June 13, 1971, Mrs. Geraldine Broderick gave birth to nine children in the royal hospital of Sydney Australia. 5 were boys and 4 were girls. Of course, we often hear of women giving birth to 3, 4 or 6 children at a time.

We Feel Thirsty

Why do we feel thirsty?

            Why do you think we feel more thirsty when we exercise or when we are tense? Many people think that parching of mouth or throat is only caused by thirst. But, this is not true. Such parching can occur due to many other cases also. Tension or production of less saliva by the salivary glands as also produces thirst and so can nervousness. Have you ever wondered why we feel thirsty? Present in our blood. The body tissues also contain these two substances. Under the normal condition, the proportion of these two materials in blood remains constant. If due to some reason, the amount of water in blood gets reduced, the proportion of these two materials in blood remains constant. If due to some reason, the proportion of the two materials also changes. In such a situation, the thirst center located in the brain sends signals to the throat. As a result of this, the throat starts contracting. This contraction makes it dry ad we start feeling thirsty and want to drink water.
We feel thirsty when the amount of water in blood gets reduced
            However, sometimes, the salivary glands secrete enough saliva and our stomach and blood too have enough water and yet we feel thirsty. For example, when man drinks liquor he takes enough quantity of slated preparations along with the drink. Though the amount of water goes on increasing with the intake of liquor, consumption of salted foods also increases the quantity of salt in blood. As a result of this, the amount of salt in blood exceeds the normal level. This disturbs the normal proportion of salt and water in the blood. In such a situation, we feel thirsty. Excessive thirst may be a symptom of diabetes or kidneys ailments. In such cases, immediate medical check up should be undertaken.

One of our Feet Bigger than the Other

Why is one of our feet bigger than the other?

            You may not believe this but our feet differ in size from each other. Have you even measured or compared one of your feet with the other? What did you notice? If we carefully measure our feet we will observe that the right foot is slightly bigger than the left one. Do you know why it is so?

            The structure of our body is not completely symmetrical. There is a little symmetry between the left and right sides of the body. If we notice carefully, we find the right side of our face is slightly more developed than the left side. The length of the right leg is slightly more than that of the left one. The right hand is slightly bigger than the left one. Our heart is located on the left while the liver on the right. The inner constitution of the body is not in complete symmetry. That is why even the development of bones is slightly a symmetrical. Because of this a symmetrical development, our right foot is slightly bigger then the left foot.
Our right side is slightly more developed than the left side
            The asymmetrical structure of the body affects us in many ways. One of the effects of this is that we are not able to walk in a straight line if we are blind folded. We start moving in circles. This is true of animals also.

            Are you curious about why the right side is slightly more developed than the left one? Though nothing can be said with certainty about this, scientist hold the view that since most of the people use their right limbs more often for any work, their right side gets more developed than the left. 96% of the total population of the world uses right hands more than left ones. Only 4% are left handed. The brain controls the use of the right or the left hand. It is the left part of the brain, which regulates the functioning of the right limbs, and the right part of the brain controls the left limbs of the body. In the world, greater number of people has the left side of their brain more developed than the right one. Hence, the number of right hander’s is also large.

Human Skin has Different Colors

Why does the human skin have different colors?

            Have you noticed that people form different countries and race have different skin colors? For example, people in the northern Europe have white skin whereas those in the western Africa have black skin. People in the Southeast Asia have yellowish skin. Do you know the reason for the variation in this skin color?
Color of human skin depends on the pigments present in the body

            The color of the human skin depends mainly on three pigments or coloring materials found in the body. The first of these is called melanin which is a brown substance. If concentrated, it appears black. The second is called carotene which is a yellow substance. And the third is called hemoglobin which is the red pigment of the blood. In the absence of these pigments the color of the skin will be creamy white. The mixture of these three in different proportions produces the different colors of the skin. A man having more melanin will have dark complexion while the man having more of carotene will have yellowish skin. Melanin and carotene are found in the deep epidermis in all skin types.

            The tissues of the body produce more melanin when exposed to the ultraviolet rays in sunlight. That is why the color of the skin of the people who live in tropical regions is very dark. When we work in the sunlight continuously for days, our skin becomes dark. People living in the colder countries have white skin, because their skin contains smaller quantities of melanin. The deficiency of these pigments in the body produces white spots on the body. This disorder is called leucoderma.

            The color of the skin depends partly on the amount of blood circulating through the dermis and the texture of the dermis. Since the texture varies considerably in different people, the light that falls on the skin is not always reflected in the same way. This is why the color of a person’s skin varies from place to place.

Process of Respiration

How do we breathe?

            Breathing is essential for all living beings. It is an involuntary reaction that takes place continuously. Men, animals, birds, insects and plants- all need oxygen, which they get form the air through respiration. However, different creatures breathe in different ways. Some breathe through lungs, some others breathe through their skin. The earthworm is one animal that breathes through its skin. Do you known how man breathes and what happens in the body during the process of respiration?
When diaphragm pulls down, it gives lungs more space to suck sufficient air, when it relaxes, it forces some of the air out of lungs.
            We, human beings, inhale air through the nose or mouth. The nose and mouth are jointed in the back of the mouth in an area called pharynx. The air inhaled goes to the lungs through the windpipe. There are two lungs in our body- one on each side of our chest. They are made up of tissues shaped like soft bags. Each lung has millions of air sacs, which get filled and enlarged when air is inhaled. When it is exhaled, they contract.

            The energy releasing process, which utilize the oxygen and produces carbon dioxide, is termed as tissue respiration or external respiration. In man, external respiration is the process where by air is breathed from the environment into the lungs to provide internal respiration.

            The oxygen, which is inhaled, is circulated throughout the body by the blood. It oxidizes the food materials. During the process of oxidation, carbon dioxide, water and other substances are produced. The same carbon dioxide is expelled when we breathe out. When we do some physical work or exercise, we need more energy. For the production of more energy, we need more oxygen. That is hwy the rate of breathing becomes fast when we do any hard work or physical exercise.

            Normally, a newly born child breathes 60 items per minute. A 15 years old child breathes 20 times a minute and an adult 16 to 18 times. The rate of breathing is faster in adults than in old people. The respiratory center in the brain controls the process of breathing. This center is sensitive to the amount of carbon dioxide in the blood. If there is an increase in carbon dioxide such as during exercise, this center sends signals to control breathing. As a result, the person breathes faster.