How is soil formed?

          Soil is the upper most surface layer of the earth in which plants grow and on which directly or indirectly, all life depends. It is composed of rocks, minerals, organic matter, water and air. It did not take one or two days for the soil to form but millions of years. Do you know how soil is formed?

          Millions of years ago, soil existed in the form of rocks. Since then weather and other natural forces like wind, rain, snow, water, heat etc. had been interacting with the rocks to break them into smaller fragments. These forces further converted the rock-pieces into sand. Bacteria, carbonic acid and other micro-organisms converted this sand into soil. In course of time bacteria converted the bodies of dead plants and animals also into soil.



          Soil is classified according to its colour, texture, chemical properties and climate. Colours of soil range from yellow and red to black. Soils are also categorized as acidic, alkaline and neutral. Extremely acidic or alkaline soil does not support plants. 





          There are three main types of soil a) Pedalfers - associated with temperature, humid climate, contain iron and aluminium salts, b) pedocalo - associated with low rainfall regions, contain soluable substances such as calcium carbonate and other salts and c) Laterites - tropical red or yellow soils heavily leached and rich in iron and aluminium. Based upon soil classifications, modern farming and plantation are made to yield maximum returns.



          An organic matter called humus is constantly being added to the parent soil. Humus makes the soil more fertile.



          Deep, well developed soil is divided into four layers called horizons. The top layer, where most plants grow, is called the A-horizon or top soil. This layer is rich in organic material and contains some minerals. The next is called B-horizon or sub soil. It is rich in minerals, especially in clay, but with little or no organic matter. Farmers often mix the A-and B-horizons by ploughing. The third is called C-horizon and it is a layer of weathered and shattered rocks. It is called the fragmented rock. It is quite similar to parent soil. The last layer is D-horizon or bed rocks. 


What are pain relievers?

          A pain reliever is a drug that reduces pain without causing unconsciousness or complete loss of feeling. In medical terminology, they are called analgesics. There are two main types of analgesics: The peripherally-acting analgesics or non-narcotic pain-relievers and the centrally acting analgesics or narcotic pain-relievers.

          The first type acts on any pain associated with muscles or bones or their related structures. Hence these are called peripherally-acting analgesics or ‘mild analgesics’. The most common of these is aspirin. Its active constituent is acetylsalicylic acid. It was first synthesized in 1899, and produced in huge commercial quantities ever since. Other analgesics of this group include analgin and paracetamol. These are used to relieve headaches, rheumatism and other body pains.



          The second groups of pain killers, the centrally-acting analgesics are very potent drugs and include substances derived from opium, an extract of the poppy plant. Two such analgesics are morphine and heroin. In the brain they depress the activity of the cortex, and thalamus which is the part that receives messages from the body’s pain receptors. They are very effective and act instantly when injected into a muscle or vein. They are only used by physicians for relieving intense pain of those suffering from cancer, heart attack or severe injuries involving broken bones or wounds. Some common drugs of this group are Codeine, Pentazocine and Ethoheptazine.



          Both types of analgesics have a number of side effects. For example, aspirin can irritate the stomach, cause indigestion or in serious cases it may even lead to an ulcer. If used indiscriminately, it may cause anaemia.



          Morphine drugs can cause nausea and vomiting, but this side-effect can be blocked by giving the drug Cyclizine along with it. Morphine and its allied drugs can cause addiction when used over a prolonged period.



          Some other analgesics such as antipyretics are used to bring down fever. In severe cases or while carrying out a surgical operation, doctors apply many anaesthetic drugs to deaden pain.



          These drugs are available under different brand names. Aspirin is available in the brand name of Disprin, Mejoral etc.; paracetamol is available in the name of Calpol, Crocin etc. Novalgin is an analgin whereas Fortwin is a brand of Pentazocine. It is always advisable to check the constituents before buying these drugs. 


How can we test the purity of milk?

             The instrument used to assess the purity of milk is called a ‘lactometer’. It is a cylindrical vessel made by blowing a glass tube. One end of the glass tube is blown in the form of a bulb and filled with mercury. The other end is blown in the form of a thin tube and sealed. For calibration it is dipped in pure milk. The point up to which it sinks in the pure milk is marked ‘M’. After that it is put in water and is marked ‘W’ at the point up to which it sinks in water. It sinks less in milk than in water because milk is denser than water. The portion between ‘M’ and ‘W’ is divided into three parts and marked as 3, 2 and 1 to indicate the level of purity.

              Whenever we want to test the purity of milk, the instrument is put in milk. If it sinks up to the mark ‘M’, the milk is pure. If the milk is not pure, but mixed with water, it would sink to a mark higher than ‘M’. When the instrument stands at the mark 3, the milk is 75% pure. At the mark 2, the purity is only 50%. Mark 1 indicates a purity of 25%.



            Even though lactometer is commonly used to measure the purity of milk, yet, it is not a very reliable instrument. It has been observed that in the case of skimmed milk (denser than pure milk) that the lactometer fails to give the correct assessment of the purity, if the density of the skimmed milk is made equal to that of the pure milk by adding water in an appropriate proportion.


Who created the Frankenstein’s monster?


           In the 18th and 19th centuries, science fictions with an element of horror became quite popular with the masses. An Englishman named Horace Walpole first introduced horror as a permanent feature in most of his writings during the 1760s. Since then many writers started writing such stories including science fictions with amazing success. The Frankenstein’s monster is one such example that attained worldwide popularity.



           The story of Frankenstein was published in 1818 which had a scientific flavour with imagination. It is about the creation of a monster that ultimately destroys its creator. With its elaborate narrations of mystery, horror, outrage, madness and spirit of revenge - this character maintains the trend first started by Walpole. The basic idea behind the creation of the monster was to show the power of science - how a dead person becomes alive and the subsequent consequences of it. The trait induced in Frankenstein makes it a reactive and suffering creature that wavers between good and evil.



           But do you know who the creator of Frankenstein - the monster was? She was Shelly Mary Wollstonecraft, the daughter of William Godwin and second wife of the famous poet P.B.Shelly. She was born on 30 August 1797 in London. She spent much of her life editing her husband’s works after his death. Among the novels she wrote, the most famous was Life and Adventure of Castruccio.



           However, in spite of her many notable works, her name is mainly attached to the creature she portrayed in Frankenstein. This novel was transformed into feature films in many versions all over the world.



           Mary Shelly died on 1 February 1851 at the age of 54. 


What is a Hydrogen Bomb?

          Soon after the development of the atom bomb in 1945 scientists started developing a more powerful bomb. As a result, they managed to develop another highly destructive bomb called the ‘hydrogen bomb’. The first hydrogen bomb was tested in 1952 by the American scientist Edward Teller and his team. It was a 10 megaton bomb, about 700 times more powerful than the atom bomb dropped in Hiroshima.

          The hydrogen bomb makes use of the phenomenon of ‘nuclear fusion’. In the fusion process, four hydrogen nuclei combine at extremely high temperature to form one helium nucleus. In the fusion reaction tremendous amount of heat energy is liberated. Similar reactions take place in the sun and other stars due to which, they have been producing continuously enormous amounts of heat and light energy. 



  



       The shell of the hydrogen bomb is made of a strong alloy. Two isotopes of hydrogen (deuterium and tritium) are kept inside this cover. One atom bomb is also enclosed in the same shell to initiate the fusion reaction. When the hydrogen bomb is to be exploded, the atom bomb is made to explode first. It produces a temperature of millions of degrees. At this temperature, deuterium and tritium combine together to form a helium nucleus and produce huge quantity of heat. This reaction is completed in one millionth of a second. In fusion, not only the helium nuclei are formed but neutrons are also produced. These neutrons carry out the fission reaction in uranium by which heat is continuously produced to carry out fusion reaction. That is why this bomb is more powerful. For peaceful uses, they can be modified so that the radio activity produced is minimal.



          So far hydrogen bombs have been developed by USA, Russia (former USSR), UK, France and China. Erstwhile USSR tested a hydrogen bomb in 1962 whose power was equivalent to 62 megaton TNT. 


How are valleys formed?


          The wide, broad plains or uneven tracts with gradual slopes between the mountains are called valleys. They are found in the mountains all over the world. Srinagar is one of the beautiful valleys in our country. Do you know how valleys are formed?



          Most of the valleys were formed by rivers. When streams originate on hill top, their water flows down the side of the hill. Because of the steepness of the slope, the river flows very fast and the force of water eats into the hillsides, forming a narrow V-shaped bed. With the passage of time, it becomes U-shaped when the water from other sides joins it and its breadth goes on increasing. Eventually the banks of the river become flat and the floor of the river widens. The area almost becomes like a plain. This is how a valley is formed. It takes thousands of years for its formation.



          Some valleys have been formed by glaciers. Glaciers are slow moving rivers of ice. The ice grinds deeply into the ground and at the same time smoothens out any ridges in its path. The glacier picks up all the rocks and other projections that come in its path, breaks them up and redeposits them smoothly over the ground. This makes the ground smooth and a U-shaped valley comes into existence.



          Sometimes the river changes its direction and thus the river bed becomes dry. The valley formed in this manner is called a dry valley.



          Sometimes when land sinks between two fractures in the earth’s crust, a valley is formed. These valleys are called ‘rift valleys’. The most famous valley of this type is the Great Rift Valley, which extends to more than 5000 km from Syria to East Africa. Narmada, a famous river of India, also flows through a rift valley.



          All the ancient civilizations started in the valleys only.



 


What is LPG?

         The term LPG stands for liquefied petroleum gas. LPG is commonly used for domestic cooking purposes. It is supplied in gas cylinders that need to be replaced when their fuel contents are consumed. The supply in gas cylinders contains a mixture of liquefied butane and iso-butane under pressure. The mixture remains a liquid under pressure but the highly volatile liquid fuel in the cylinder evaporates when pressure is released. The gaseous mixture starts going into the burner of attached stove or oven. Here it is ignited and the blue flame is used for different purposes.

         LPG is used as a cooking fuel. This is also used in water heaters, space heaters and furnaces. This gas is also used to heat incubators and brooders, to sterilize milking utensils and other equipments, dry fruits and vegetables and prevent frost damage.



         Moreover, LPG is highly combustible and forms an explosive mixture with air, therefore, any leakage followed by its mixing with air can cause a severe explosion just by the ignition of one match stick. In order to make gas leakage easily detectable some strong smelling substance is added to LPG. Before igniting the match stick we should be sure that there is no such smell near the gas cylinder or in the kitchen.



 


What is an Alkaline Battery?

A battery is a device that produces electricity by chemical action. A battery contains one or more units called cells. Each cell can produce current.        



There are three main types of dry cell batteries: carbon-zinc, alkaline and mercury. Here we are describing an alkaline battery.



An alkaline dry cell battery is more powerful than carbon-zinc battery. It lasts five to eight times longer than a carbon-zinc battery. It has carbon and zinc as electrodes. Instead of a carbon rod extending from the top, a nail like collector (1) is inserted from the bottom. The granules of zinc which form the anode (2) are made uniform in size and shape. The electrolyte - a solution of potassium hydroxide - is in direct contact with the anode, ensuring that the anode is exhausted by the end of the battery’s life. The manganese dioxide cathode (3) is made by electrolysis. The additional oxygen increases the reactivity of the cell. Alkaline dry cells are used mainly for portable radios. 


How is synthetic rubber made?

                  Rubber, which is in common use, is of two types, namely, natural rubber and synthetic rubber. Natural rubber comes from the juice of a tree while synthetic rubber is made from chemicals.



                 Synthetic rubber was first developed before 1900 from the hydrocarbon isoprene which was synthesized from turpentine. Almost all types of synthetic rubber are obtained from petroleum industry. Important sources are styrene, acetylene and butadiene. Two of the most important types of synthetic rubber are butyl rubber and styrene-butadiene rubber. These two rubbers along with natural rubber made up about 90 percent of the worlds’ demand.



                Natural-synthetic rubber is also an important rubber for the industry. These are the synthetics that duplicate the molecular structure of natural rubber and can be used interchangeably with the natural product. Since World War II, a lot of products such as foam rubber have been directly made from natural rubber latex or from synthetic equipment.



 


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How does a dish washer work?

A dishwasher is a modern domestic appliance that cleans and dries utensils automatically. These machines generally worked on the principle of passing the dirty dishes under jets of hot water by means of conveyor belt or revolving basket. Modern dishwashers have reversed the procedure. In these dishwashers the utensils are cleaned by revolving jets of water above and below the basket.



                  A modern dishwasher contains heater, pumps, motors etc. and requires a water supply. It is housed in a enameled cabinet. A drop down door enables the plastic coated basket to be pulled out on slides or rollers for loading. The door is fitted with a micro switch to shut of all operations.



                  A dish washer generally has several programmes which may be selected by means of keys or push buttons, depending on the type of utensils to be washed and the type of food residues to be removed. In a typical programme, dirty crockery and cutlery are loaded into specially designed carriers. To wash and rinse, water is sprayed from above and below the dish basket by whirling arms through which the water is pumped, each of the arms have several spray holes in it. The pressure of the water itself makes the jets spin around. The first part of the cycle uses water containing detergent to dissolve grease and grime. The detergent is loaded into a compartment in the lid which automatically releases the right amount at the proper point in the cycle. In the second part of the cycle, clean water rinses away the soapy water. Then a heating element warms and dries the utensils.



                A timing device automatically controls the selected cycle, it is often operated by means of round calibrated knob. Some machines have pilot lights which indicate the part of the cycle in operation. These machines are proving very useful as kitchen aids.



 


How does a washing machine work?

          A washing machine is an electrically operated machine used to clean dirty clothes. Most washing machines have a round drum that spins to wash the clothes. The clothes tumble over each other as it turns, which helps the detergent to clean them.

          In a modern washing machine, a set of buttons allows the user to select a pre-programmed cycle of washing, rinsing and removing the water. At the start of the cycle, water pours in through an electrically controlled inlet valve. Once the water reaches a certain level in the drum, this is detected by a sensor that turns off the inlet valve. The pressure of the water in the inlet pipe helps to shut the valve firmly. If required, the water is then heated by the machine’s heating element. Once the preset temperature is reached, a thermostat switches off the electric supply to the heater. The dirty clothes are cleaned by the detergent mixed in water in the spinning drum. The clothes are rinsed in clean water to remove the soapy water.



           The clothes may be washed and rinsed several times in the washing machine to get them really clean. Then they are spun very quickly to remove most of the water so that they may dry quickly. This forces droplets of water out of them by centrifugal force. After spin-drying, the clothes can be air-dried or dried in a tumble dryer.



           Washing machines, now a day, are being used on a large scale. They save time and labour of washing the clothes. 


What are the constituents of milk?

          Milk is white nutritious liquid produced by female mammals as food for their young ones. Milk obtained, especially from cows, buffaloes, goats, etc. is drunk by human beings. Butter, cheese, curd, etc. are also made from it.

          Nothing definite can be said as to when exactly man started using milk but it is certain that around 5000 years ago man had started domesticating milk-producing animals.



          Cow, buffalo, sheep and goat are the main milk producing animals. In northern Europe, milk from reindeer is also used. In the Middle East countries, goat’s milk is commonly used for consumption.



             From the very beginning, milk has been known to be a perfect food. It contains all the nutritional elements like sugar, proteins, fats, vitamins, minerals, salts and water needed to our body. Cow’s milk contains 87.2% water, 3.7% fat, 3.5% proteins, 4.9% sugar and many minerals and vitamins. The milk of various other animals contains all the above mentioned nutrients in varying percentages.



             We extract fat present in milk in the form of butter. Fats give us extra energy. The proteins present in the milk strengthen the muscles of our body. The sugar is easily absorbed by the body and acts as a fuel. Minerals like calcium and phosphorus are useful for our bone formation. Vitamins A, B, C, D, E, K and niacin present in milk reduce the vitamin deficiency of our body.



              Milk gets spoiled very soon. As such, it should be cooled to 10° C within two hours of milking. It should be maintained at this temperature till it is transported to other places. Its fermentation can be prevented by boiling it several times a day.



              In many countries, pasteurized and homogenized milk is sold. Skimmed milk is popular with dieters because most of the fat is removed before the milk is sent out for sale.



 


What is Water?


Like air, water is essential for life. Without water we cannot survive for more than a few days. Human beings, trees, plants and animals all need water for their survival. Perhaps, that is why nature has covered more than seventy percent of the earth’s surface with water. About 97% of water on earth is in the oceans.



Water is a compound of hydrogen and oxygen. It contains two parts of hydrogen and one part of oxygen by volume. Pure water is colourless, odourless and tasteless. We get water from rivers, lakes, fountains, wells, rains, oceans etc. Water exists in three states - solid, liquid and gaseous. Normally it is found in liquid state, but when it is cooled to zero degree centigrade, it freezes into ice. When it is heated to 100° C, it is converted into steam.



Water obtained from nature is not pure, but contains many salts and minerals dissolved in it. Due to these impurities, water develops some taste. Some of the impurities make water hard. Hard water does not form lather with soap. The hardness of water is of two types - temporary and permanent. Temporary hardness is due to the presence of bicarbonates of calcium and magnesium. It is removed by boiling the water. Permanent hardness is caused by the presence of chlorides and sulphates of calcium and magnesium. This hardness is removed by mixing sodium carbonate in water.



Water has many fascinating properties. For example, ice is lighter than water. That is why ice and big icebergs float on water. Water has the highest density at 4° C. Due to this property, during winter, only the upper surface of water in lakes and ponds freezes but the lower portions do not freeze. Hence marine life can survive in such lakes and ponds easily. The structure of water is such that most substances dissolve in it. Water is regarded as a universal solvent. Sea-water is saline because many minerals remain dissolved in it. Air dissolves itself in water enabling aquatic animals to breathe inside water. Water is a liquid which is not easily evaporated. That is why soil retains moisture for a longer period and trees and plants are, therefore, benefited by this.



Water content in different living organisms varies. Trees and plants have 60% to 80% water, fresh fruits 85% to 95% and plants living in water, contain 98% water. Human body contains 65% water.



A civilized man on an average uses 35 gallons of water every day for drinking, bathing and washing. One should be careful about ones drinking water. Often water contains germs of dangerous diseases like typhoid, cholera, diarrhoea, dysentery etc. Boiled water is, therefore, hygienic. Water can be made free from germs by filtering, boiling and mixing potassium permanganate or bleaching powder in it.





 


 

What is Uranium?

           Uranium is a silvery, radioactive, metallic element. It occurs as uranium oxide in the mineral pitchblende.



           Uranium was discovered by the German chemist Heinrich Martin Klaproth in the year 1789 from a mineral called pitchblende. He named it ‘Uranit’. But, after a year Klaproth changed its name to Uranium after the planet Uranus. By the end of the eighteenth century scientists had already made many compounds of this metal. In 1896 Henry Becquerel discovered radioactivity in Uranium.



            Uranium is a shining metal of white colour but it turns black when it comes in contact with the atmosphere. Uranium is a very heavy metal. The weight of a cubic foot of this metal is approximately half a ton. In the beginning, it was used for dyeing silk and porcelain vessels.



            Natural Uranium is a mixture of two main isotopes - Uranium-238 and Uranium-235. 99.27% of the Uranium found in nature is uranium-238 and 0.72% is Uranium-235.



            Two of its unique properties have enhanced its utility throughout the world. The radioactive rays coming out from the nucleus of Uranium are very useful. These rays are used in agriculture, industries, biology and medical research. The second use of Uranium is in the field of nuclear energy. In 1938 the process of nuclear fission was discovered by bombarding Uranium nucleus with neutrons. The nuclear fission is the process in which the nucleus of the Uranium-235 atom is split into two parts by neutron bombardment, hence tremendous energy is produced. The atom bombs were made through this process only in 1945 which were used against Japan in World War II. After the development of the atom bomb, its utility increased tremendously.



 


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How is silk produced?

                   All of us are familiar with the soft and beautiful clothes made of silk. Silken cloth can be made so thin that a full bale of it can be passed through a small ring. Do you know how it is made?

                   You may be surprised to know that silk threads are made by small insects called silkworms. A silkworm makes a cocoon around itself which increases in size as the worm grows bigger. When the cocoon becomes big, it is heated in hot water. In this process the worm dies and silk is obtained from the cocoon. If this worm is allowed to grow it turns into butterfly.



                  The Chinese knew the art of making silk four thousand years ago. There is an interesting story in this regard. It is said that the Chinese Queen Si Ling-Shi once put a silkworm by mistake in a water pot which was meant for washing hands. The next day she saw silk threads coming out of the pot. Fascinated by it, she started keeping silkworms and used the silk prepared by them for wearing. For years, the Chinese kept the art of making silk a secret. The Japanese were the first to know this secret in the third century. Around A.D. 550, King Justinian of Byzantium sent two Persian monks to China as spies. On their return these two spies brought eggs of the silkworms in a bamboo tube. After this, art of obtaining silk from the silkworms slowly spread throughout the world.



                  Today, countries like China, Japan, India, France, Spain, Russia and Italy produce silk.



                  In the beginning of the summer season, the female worm lays about 500 eggs on the leaves of mulberry. In around ten days, larvae come out of these eggs. They are carefully examined and the diseased ones are separated and destroyed. The silk worms are brought up on the leaves of the mulberry. Silk is made from the juice coming through a hole in the mouth of the silk worms. In about 25 days, they give out cocoons. One-fifth of the weight of a cocoon is silk. The silkworms are killed in hot water and silk is spun out. A cocoon has one long thread measuring from 500 to 1300 metres. It is almost as strong as a steel wire of the same thickness.



                 Silk blended with cotton as well as with other synthetic fibres too is produced and is very beautiful. For beauty and finesse, Italian silk is regarded as the best in the world today.