My Science School

               Pain is an unpleasant feeling that is usually caused by an injury, disease or other abnormality of the body. It is a warning that something is wrong somewhere in our body. Do you know why do we feel pain?

               We feel pain if something burns or presses hard on the end of certain nerves which are known as pain receptors. These receptors are located throughout the body as well as in the skin. Each pain receptor is a part of a nerve which carries pain impulses to the brain.

               Superficial pain is caused by receptors in the skin. A person can tell the location of the superficial pain as the skin has a large number of pain receptors. It is very difficult to pin-point the location of pain in internal regions because there are only a few pain receptors there. Sometimes deep inside the body, pain may be experienced that might get transferred to some other part of the body at some distance from the actual source of the pain. Toothache is one example of such pain.

               The best treatment of pain is to treat its cause. It can be controlled by some drugs called pain killers. Aspirin is one such drug. For controlling severe pain narcotics are usually used. Long term or chronic pain is treated by interrupting the pathways of the brain or spinal cord. Opium, morphine and heroine are the important narcotics used for this purpose. These drugs cut off the paths of the nerves which carry the pain messages to the brain. The biggest disadvantage of these drugs is that they lead to addiction. In modern times, chemists have invented anaesthetic drugs and other pain killers having fewer side effects to deaden pain caused by any disease and injury. 

          We know that construction of a huge structure requires thousands of slabs and other material like steel or stones to make it functional. Similarly billions of cells, tiny or long, subtle or sturdy, construct a living being. All the cells in the human body are not alike. They differ greatly according to the tasks that they have to perform. Muscle cells, for instance, are long and have the ability to contract and shorten the muscle. There are two types of muscle. Some work when our brain tells them to perform. For instances, when we pick up a load, our brain sends signals to muscles in our arms. Other muscles work even when we are asleep, for example, our stomach muscles go on churning the food we have consumed. The cells of the skin are mostly quite flat as their task is generally to cover a surface of the body. It acts as a barrier to infection and prevents the body losing water and heat too rapidly. In fact nature has designed cells to carry out every necessary bodily task.

          When many cells of the same or of different types are arranged together they form a tissue. These cells are put together by a substance called matrix. Its function is similar to that of the mortar placed between layers of bricks. The form of a tissue is determined by the nature and amount of the matrix and the type of cells. For example the quantity of matrix in the skin tissues is very small while in bone tissues it is quite large. The matrix is made from calcium phosphate and carbonate and magnesium phosphate and carbonate. They strengthen the bones. Our blood is made up of pale liquid called plasma and millions of cells or corpuscles. The blood cells float in it quite freely.

          Different types of tissues arranged together form an organ which performs a particular task. In the human eye, for example, there are many different tissues, all of which assist in the process of seeing. Though eye is a very small organ of our body, it is very complicated in structure. It is made of different types of tissues. Some organs like liver are much bigger but they are largely composed of a single type of tissue.

          When several organs work together to perform a special and complicated task, they are usually called a system. Digestive, respiratory, excretory etc. are the different systems which perform different tasks. Every system in the body helps each other and provides energy. For example, many of our activities are controlled by different parts of our brain. The hind brain, which consists of medulla oblongata, controls the heart-lings and digestive system.

          All warm blooded animals and human beings have their own system which varies in different degrees in terms of functional behaviours. 

            When we decide to get up early in the morning at a fixed time, we wake up without the help of an alarm or even a watch. Our body in fact does have a regular daily rhythm and this makes us aware of time. We usually sleep for eight hours every night. Depending upon the temperature of the surroundings our body temperature also undergoes a change and so does the speed of our heartbeat.

            Now the question arises, whether these rhythms depend on a sort of built-in-clock or on the daily changes of light and darkness? A famous experiment gave some clues to scientists to find an answer to this question. For several months the researchers lived alone in a cave where they did not even see daylight and had no idea about the time. They camped in tents, with gas heaters, lights, books and even a record player to make life in the cave bearable. Frequently they used a special phone to call the base camp above ground, reporting when they woke up, ate and went to bed.

            In another experiment people lived in specially built underground apartments. They, too, reported regularly to scientists outside.

            Most of the researchers in these experiments slept and wake up regularly on time. Only few lived on irregular schedules.

            On the basis of these experiments, we may conclude that our body has a built-in-clock. In fact the clock does not exist literarily. The most probable answer could be that our body responds involuntarily to a fixed regular time of all actions or even to any conceived time in mind. The actions in response to time may be the results of involuntary body actions or conditioned reflex actions. When the body is accustomed to a particular time for a particular action or become responsive to a pre-set time in mind then it works accordingly in set times. Researchers are going on this subject and it is hoped that someday scientists would be able to find a definite answer to these questions related with built-in-clocks in our bodies.

               Arthritis is the name given to a group of diseases that cause pain in the joints of the body. Arthritis in general, is a disorder of the joints. In fact, the word arthritis is of Greek origin, which means inflammation of a joint. In these diseases the connecting tissues of the joints get inflammed. Sometimes it can even cripple a patient.

               Although arthritis is more common in old age, it can occur to a person of any age. As per the available data the disease attacks twice as many women as men. It is not restricted to human beings only. It may even attack the animals. Today scientists have sufficient evidence to prove that dinosaurs suffered from arthritis. It may be caused by inflammation or infection in the joints.

               Sometimes it is a symptom of another disease. There are various forms of this disease but the exact cause of most kinds of arthritis is not yet known. Some types of arthritis are caused by injuries or by high content of some special chemicals in the body. It may also be caused by the wearing a way of cartilage in old age or by an allergic reaction involving joint tissues.

               A new form of arthritis has been discovered which is believed to be caused by a virus. It spreads among human beings by a bite from an insect, known as tick.

               In this disease joints get swollen and crooked. The patient feels pain and finds it difficult to move. There is no absolute cure for arthritis, although it is usually treated by aspirin-type drugs to reduce pain and swelling. Physiotherapy has also been found very helpful in its treatment. Vigorous massage and transmission of sound waves into the body is also very effective in curing this disabling disease.

               The treatment of arthritis varies according to the stage of the disease in the patient at the time of medical check-up.

               In preliminary stages the treatment is directed towards the relief of symptoms, improvement in general health and performance of some physical exercises. In some kinds of arthritis, diseased joints can be replaced with artificial ones. 

          After taking meals most of us tend to belch. Some people even belch whenever they want to. Do you know why do we belch?

          Every time we swallow food, a little air goes down with it. A muscular valve at the top of our stomach opens to let in whatever we have consumed and then closes quickly. This keeps strong stomach juices from sloshing out.

          Usually, some air is always present in our stomach. A little gas is produced during the digestion of food. Sometimes carbohydrate bubbles in soda water enter the stomach when we drink soda water. It helps to release pressure of gas generated in stomach due to indigestion. When too much of air and gas collects, our brain gets a signal that something should be done. As a result muscles of our stomach tighten up and the valve opens. Thus we get a burp. The noise is produced by the air and the gas vibrating in the pipes that go out of our stomach. Thus we see that belching is a mechanism and a kind of reflex action by which the extra gases collected in the stomach are released. 

 

          The recording of potential changes produced by the eye when the retina is exposed to a flash of light is called the electroretinogram, or in short ERG. Retina is a light-sensitive area at the back of the eye connected to the brain by the optic nerve. To record an ERG, one electrode is mounted on contact lens that fits over the cornea and the other is attached above the ear or forehead.

          An ERG signal is more complicated than a nerve signal because it is the combination of the effects taking place within the eye. The general pattern of an ERG is shown in the figure. From the medical point of view, the ‘B’ wave is the most important because it arises in the retina. If a patient is suffering from ‘Retinitis pigmentosa’ the ‘B’ wave would be absent in his ERG because of the inflammation of the retina.

          The recording of the potential changes due to eye movement is called electroculogram. In short, it is known as EOG. To record an EOG, a pair of electrodes is attached near the eye. An EOG can record horizontal and vertical movements of the eye. EOG also provides information about the orientation of the eye, its angular velocity, and its angular acceleration. Scientists have studied the effects of drugs on the eye movement. By an ERG, eye movements during sleep can also be studied. EOG is very rarely used in the routine check up for eye ailments.

          Retina is an important part of the eye. It is a layer of special cells at the back of an eye ball and contains sensory cells capable of converting light into nervous messages that pass down the optic nerve to the brain. Images of the objects are formed on the retina. So with the help of an ERG, certain major diseases of the retina can be detected. Damage to the retina can cause blindness.

          Just as an engine needs fuels like coal, petrol etc. to run, similarly our body also requires fuel which provides us energy to work with. The substances which act as fuel or energy for our body are fats, carbohydrates, proteins etc. — the substances which our food consists of. Whatever food we take it gets burnt with the help of oxygen which we get from in-breathing, thereby releasing energy by breaking into these constituents. This energy thus produced is used in the performance of all of our voluntary and involuntary body functions. For instance, protein is required for growth and tissue repair while vitamins and the minerals are necessary for the proper functioning of various body organs.

          So, we need to supply these substances regularly to our body for its efficient functioning. That is why we take food regularly.

          Out of these substances taken as food our body absorbs and utilizes useful ones and rejects those which are not needed, in the form of waste material. We excrete daily about 2 kg of urine and stool. Carbon-dioxide also comes out during out-breathing as a waste material. About 400 gm of water comes out through the process of sweating and out-breathing.

          Human body temperature remains constant between 98°F and 99°F. This 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 which 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.

 

               The word consciousness in psychological term refers to the condition of alertness of the organism. The brain is the control centre of the body’s nervous system and plays a major role in man’s thinking, remembering, alertness and vice-versa. 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 will be very 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 consciousness. He would be regarded as unconscious if he falls asleep.

               These are different states of consciousness 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 to make person more active beyond his normal ability. Such medicines affect the central nervous system and produce such abnormal conditions. Caffeine in a strong coffee or tea can act as a powerful stimulant for some people. Too much alcohol can produce dozing effect and finally unconsciousness.

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

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

          Cholesterol is an organic compound belonging to the steroid family and occurring either in a free state or as esters of fatty acid in practically all animal tissues. The molecular formula for cholesterol is. In a normal man it is about 0.3 percent of his average weight. It is the starting material from which the body produces bile acids, steroid hormones and pro-vitamin substances in the body. It is used by our body to help the digestive system as well.

          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 a certain level can be harmful for our body. Excess of fat and cholesterol get deposited in the walls of arteries causing blockage and hardness thus obstructing the free flow of blood. Due to this, quantity of blood flowing in the arteries decreases and consequently the oxygen supply to vital parts of our body is also decreased. This condition is medically termed as arteriosclerosis. Small blood clots that would normally pass through blood vessels may get trapped by high cholesterol deposits.

          We know that coronary arteries play a vital role for the heart to function. They provide oxygen and carry blood to the heart. If a coronary artery gets blocked that particular part of the heart may stop functioning leading to 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 origin like meat, egg, butter etc. Doctors advise to avoid high-cholesterol foods by substituting unsaturated foods like fruits, vegetables, cereals and so on.

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

 

               Balloon flights have become a popular air sport these days though the number of participants is limited to a few. Balloon festivals are organized every year at different places all over the world as a competitive sport as well as for fun and entertainment. But who made the first balloon flight and when?

               The idea of a balloon flight first occurred in the mind of two Frenchmen when they watched smoke rising up inside a chimney. This led Joseph and Etienne Montgolfier to build the first man-carrying balloon. The balloon made by them was filled with hot air from a fire to provide the lift required for flying. It was the year 1783 when the people of Paris were amazed to see a sheep, a cock and a duck flying in a balloon made by Joseph and Etienne Montgolfier. But strangely the fact remains that though they made the first balloon they could not become the first air travellers. The honour of making the first balloon flight is shared by two brave men, J.P. de Rozier and Marquis d’ Arlandes. This historic flight carrying these two men was made in November, 1783. With this began the era of flying.

               But a balloon flight of this kind depended on wind blowing and the balloon flew in the direction of the wind. To overcome this drawback the first powered flight was made by fitting an engine to a balloon in the year 1852. Henri Gifford of Paris made this airship with a balloon fitted with hydrogen gas for lifting the balloon. A platform was attached below the balloon through wires and a small steam engine was fitted on this platform. The airship could be moved forwards with the help of a propeller run by the engine. This was the fore-runner of the more advanced airships and the later day aeroplanes which were run by electric and petrol engines.

               There are some interesting facts about the recent history of ballooning. A balloon called Miss Champagne rose to a height of 50 feet with 61 passengers on board on 19 Feb 1988.

               The Dutch balloonist Henk Brink made a balloon that reached a height of 328 feet with 50 passengers on board on 17 August 1988 which lasted for 25 minutes. 

               Dr. Subrahmanyan Chandrasekhar was a world famous astrophysicist. He was awarded the Nobel Prize for physics in 1983 for his outstanding researches in the field of astronomy related to the structure and evolution of stars. He shared this prize with an American professor William Fowler. Do you know why he received this honour and what are his contributions to the astrophysics?

               Prof. Chandrasekhar was born on Oct 19th, 1910 in Lahore. He was educated at Presidency College, Madras University. He got his doctorate from Trinity College, Cambridge. From 1933 to 1937 he worked on stellar evolution. His genius is established from the fact that he became a Fellow of Trinity College at a young age of 24. And at the age of 25 he had put forth his theory on dying stars which startled the whole world.

               In 1938 he became an Assistant Professor in Chicago University and in 1953 acquired American citizenship. In the same year he was given the Gold medal of Royal Astronomical Society.

               In 1947 Dr. Chandrasekhar became a Professor in Chicago University and the Morton D. Hull Distinguished Service Professor of Astrology in 1952. His genius is evident from the fact that his book An Introduction to the study of Stellar Structure, published in 1939 is still used as a reference book for students of astrophysics all over the world.

               In 1973 he was made a member of the Swedish Academy that awards the Nobel Prizes. His findings on White Dwarfs are internationally acclaimed. ‘Chandrasekhar Limit’ that deals with the limiting mass of the stars is again an epoch making discovery by him.

               The Mathematical Theory of Black Holes was his most important work, published in 1983. His latest book was Newton’s Principia for the common reader. Prof. Chandrasekhar passed away as an American citizen in the year 1995, within a few weeks of the publication of this book.

 

               Srinivasa Ramanujan was one of the greatest mathematicians India has ever produced. His contributions to the theory of numbers brought him worldwide acclamation. He was born in a poor Brahmin family of south India on 22nd December, 1887. Due to lack of scope, he started his career as a clerk. In his spare time he used to devise mathematical Problems himself and solve them.

               When he was 15 years old he obtained a copy of George Shoobridge Carr’s Synopsis of Elementary Results in Pure and Applied Mathematics. Having verified the results in Carr’s book, Ramanujan went beyond and developed his own theorems. In 1903 he secured a scholarship from the University of Madras. But since he devoted himself fully to mathematics and neglected other studies it was forfeited the following year.

               But undeterred, Ramanujan continued with his work in extreme poverty without employment. He got married in 1909 and began to search for a permanent employment. He obtained a clerical post with the Madras port trust.

               Ramanujan published his first research papers in the journal of the Indian Mathematical Society in the year 1911. His genius slowly gained recognition and in 1913 he began a correspondence with the British mathematician Godfrey H. Hardy that led to a special scholarship from the University of Madras and a grant from Trinity College, Cambridge. In 1914 Ramanujan went to England, where Hardy tutored him privately and collaborated with him in some research.

               Ramanujan’s genius was unrivalled. He worked out the Riemann series, the elliptic integrals, hyper geometric series, and the functional equations of the Zeta function and his theory of divergence series. In England, Ramanujan made further advances, especially in the partition of numbers. His papers were published in English and European journals. In 1918 he became the first Indian to be elected as a Fellow to the Royal Society of London.

               In 1917 Ramanujan got tuberculosis and so he returned to India. He died at Chelput in Madras on 26th April, 1920. 

               In the study of elementary Geometry we all are familiar with the concept of “Pythagorean Theorem”. This tells us that for any right angled triangle, the square of the longest side of the triangle (hypotenuse) is equal to the sum of the squares of the lengths of the other two sides.

               But do you know who invented this famous formula that still is the basic concept of the geometrical studies on triangles? He was Pythagorus, the Greek philosopher, mathematician and astronomer. Pythagorus was born during 500 B.C. in Samas, Greece, near the present city Metaponto in Italy. He migrated to South Italy during 532 B.C. to escape the tyrannical rules those prevailed there.

               But his inquisitive and probing mind always thrived him to share his ideas and thinkings among the people. These desires ultimately led him to establish an Academy at Carton — presently known as Crotona to achieve his goals. His teachings on ethics, politics and brotherhood had a great effect over the people there. His thoughts and ideas were flourished throughout most parts of Italy and Greece. But all these eventually died out towards the end of 4th century B.C., largely because of opposition from some quarters for some reason or other. But apart from his philosophical thinkings, his contribution is also credited with the mathematical concepts of the functional significance of numbers. He, in fact contributed to the development of mathematics and geometry in addition to his ideas on Western philosophy. It is an established fact that his ideas greatly influenced the thinking of Plato and Aristotle.

               In the scientific world, his theories on geometry, mathematics, astronomy, sound behaviours etc. were gratefully acknowledged. The famous astronomer, Copernicus for instance, described Pythagorus as a fore-runner of the suggestions put forward by him that earth and other planets rotate in orbit around the Sun.

               During 493, B.C. Pythagorus died at the age of 83.

 

               From the primitive age man has always known and feared earthquakes. We know about the large scale devastations they caused. Do you know who first invented a device for registering and detecting the intensity the earthquakes?

               He was Chang Heng of China. In 132 A.D. the device for registering seismic activity was invented by him. The device had a number of metal balls around the rim of an urn. It was arranged in such a way that an earth tremor would disturb a central column, operating a mechanism that dropped one of its ball into a metal holder causing a noise. The direction of the earthquake could be worked out by seeing the balls that fell and that did not.

               From this primitive device the modern sensitive seismographs evolved and a science has grown up with them known as the seismology or study of earthquakes. The Greek word Seimos means “a shaking”.

               Within the past hundred years there have been many advances in the design of the device called “Seismographer”. Seismographers give a record of movement and waves of the earth’s crust at their location. There is now seismic recording equipment fixed in every country — making continuous recordings. A heavy inert weight is suspended in the equipment by a spring and attached to this is a fixed pen that is in contact with paper on a rotating drum. During earthquake the instrument’s frame and the drum move, causing the pen to record a zigzag line on the paper. The pen does not move.

                These lines indicated the intensity and location of the earthquake. In modern observatories, at least two or three seismographers are installed. Each one is meant for monitoring the horizontal and vertical movements of earthquakes to measure and locate the exact centre of earthquake. It has not possible yet to design a seismograph to measure faithfully the movement of earth’s crust in every direction at once in response to seismic waves. However, it seems possible that earthquakes may soon be within man’s control to some extent. 

               An atom is made up of three types of elementary particles called electrons, protons and neutrons. The neutrons and protons constitute the nucleus of the atom while the electrons revolve around the nucleus in different orbits. Neutron is a subatomic particle that does not have any electric charge. Protons and electrons however carry equal positive and negative charges respectively but neutron has no such charge. The mass of the neutron is slightly greater than that of the proton. Do you know who discovered the neutrons?

               Neutron was discovered by a British Physicist named Sir James Chadwick. In the early 1900s, scientists were aware that an atom contained electrically charged particles called electrons and protons. Scientists believed that there must be uncharged particles also in an atom. In 1932, Chadwick showed that the radiation from the element beryllium, caused by the bombardment of alpha particles is actually a stream of electrically neutral particles. He called these particles neutrons. He also studied some other properties of these particles. Neutrons directly emitted from atomic nuclei are termed as fast neutron.

               Chadwick also explained the existence of isotopes. An isotope of an element has the same number of protons but different number of neutrons. It has, therefore, a different atomic weight. In 1935, Chadwick was awarded Nobel Prize for physics. Chadwick did pioneering work in the field of nuclear chain reactions. He played an important role in the development of the first atomic bomb during World War II.

               From the studies carried out on neutrons it has been found out that a free neutron which is outside a nucleus is unstable. On an average, a neutron decays in 12 minutes. This length of time is called half life of the neutron. Inside the nucleus, the neutrons are usually stable. When they decay inside the nucleus, that substance becomes radioactive. Beams of neutrons have high penetrating power and therefore they have high damaging effect on living tissues. Because of this, scientists working in nuclear establishments have to wear protective shields as a protection against harmful radiations.