My Science School

          Granite is a very hard kind of rock made up of small pieces of mica, quartz and felspar and sometimes other rocks as well. There are many kinds of granite and they may be pink, grey or white. But the most striking thing about granite is that the pieces of rock from which it is made are all crystalline and shine like a wall of snowflakes.

          One city in Scotlandcalled Aberdeen is known as the silver city, because of the way the granite from which it is built shines in the sun.

          This rock is widely used for building, and is especially useful for large engineering jobs such as the making of breakwaters. Not only does it stand up well to the weather but, unlike many other rocks, it can be quarried in huge slabs. It is also used as an orna­mental stone after being polished to a smooth surface.

          Granite is found all over the world and forms part of most of the world's mountain ranges. There is a city in the State of Illinois called Granite City, while the Mountain State of New Hampshire on the eastern side of the United States is called the Granite State on account of the granite quarries there.

          You may have heard the expression “granite features” used to describe persons. This means that they have cold, hard faces, like a granite rock.

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     The seasonal winds of south-west Asia known as monsoons are associated particularly with India because of the lives of the inhabitants. The winds are drawn to India by changes in the temperature of the great land mass. A good monsoon season with plenty of rain means a comparatively good supply of food. A bad monsoon with little rain means a bad rice crop and, perhaps, starvation for many millions.

    Monsoons come from the Arabic mausim, meaning season. The summer season monsoon is a great inrush of moisture-laden air from the ocean. The winter monsoon blows from the land to the sea.

    In India there are three seasons: the hot dry season from March to June; the hot wet season from June to November; and the cool dry season from December to March. During the hot dry season the great plains of northern India becomes like a furnace and a region of low pressure develops.

   By mid-June, the pressure is low all the way to the Equator and draws the south-east trade winds to India, filled with water-vapour as they cross the Indian Ocean. When they meet the hot dry air over India, violent thunderstorms result, followed by steady rain in July. By November India has received three-quarters of its annual rainfall.

    Then the land mass cools and the lower pressure to the south attract the north east trade winds. These bring no rain to India except to the Coromandel Coast and Ceylon, where the rainfall in late September is heavy, because the winds have picked up water vapour as they cross the Bay of Bengal.

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          The world’s highest mountain is Mount Everest on the Nepal-Tibet frontier in the eastern Himalayas. Mount Everest was named after Sir George Everest who discovered it in 1856, when he was surveyor general of India. At that time its height was estimated by trigonometry as 29,002 feet, but more recently it has been  established as 29,028 feet.

          Everest is not only the highest mountain in the world, but also the most magnificence and inaccessible. It is swept by icy winds and gripped in a coldness that often drops far below zero. There are great glaciers and crevasses, icefalls and sheer rock faces, and the rarified atmosphere as its greatest heights has defied generations of climbers.

            It was not until 1920 that the Dalai Lama of Tibet was persuaded to permit a British climbing party into his territory. Until then both Nepal and Tibet had forbidden any such intrusion.

          Several unsuccessful British expeditions were made to conquer the mountain and 16 men were lost in the attempts. In 1951 Eric Shipton made an approach from the south through Nepal. Before then all the expeditions had made their approach from the north. Shipton had no intention of attempting an assault on the summit. His object was to gather information for future expeditions.

          With the help of this information a British expedition, using light-weight oxygen-breathing apparatus and other weight-saving equipment, reached the summit in 1953. It was led by Colonel H.C.J. Hunt, later Lord Hunt.

          Nine camps were made during the climb, and on the morning of May 29 a New Zealander, Edmund Hillary, and Sherpa Tensing Norgay made the final assault. At 11.30 a.m., after a hard climb, they reached the summit.

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          Loam soil is half way between clay and sandy soils. It is the best soil for horticultural and agricultural use, containing enough clay and humus for the retention of water and for the provision of food for plants. It also has sufficient sand to allow the passage of air and the drainage of water, which prevents water logging, and enough lime to prevent acidity.

         River basins are often covered with a powdery, yellowish-grey loam called loess. This loam has been brought downstream by the river and is derived from glacial deposits of very fine silty, unconsolidated material. Some of the best farming land in the Rhine and Danube basins is composed of this soil. Other loess deposits have no connection with glacial action and are accumulation of fine material picked up by the wind in the world’s arid regions. When water is introduced into these loess areas by means of irrigation they make unusually fertile soil.

        There are loess deposits in the plains of south Russia, the Argentine pampas and China, and in lowa and Illinois in the United States. These are among the richest agricultural regions in the world.

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            Contour lines are used when maps are designed to show the physical nature of the land. They do this by linking all points which are the same height above sea level. The width between the contour lines indicates the steepness of gradients or slopes in the area. The closer the lines are together, the steeper is the slope.

            On physical maps giving the height of mountains, rivers, lakes and principal towns all areas between certain heights are gener­ally shown in the same colour. This is known as layer colouring.

            Other methods for indicating heights include relief maps moulded in plastic to the physical feature raised as on a model. Spot heights may be shown, but these merely give the heights above sea level of certain points of the map and it, does not follow that the ground rises evenly from one point to another.

            Very old maps have mountains drawn on them. Later ones have lines called hachures radiating from a central, point, with longer lines to show gentler slopes. Another system is to show the form of the land by hill shading. But none of these methods is effective as the use of contour lines.

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          The large number of windmills in Holland, or The Netherlands, is due to the fact that they were needed to pump water into the canals off the rich, low-lying land reclaimed from the' sea. Windmills are still used for this purpose today, but pump worked by electricity are more usual. 

          There is an Old Dutch saying, "God made the world, but the Dutch made Holland". They certainly did make a great part of their land by dragging it from the sea, and the battle to hold it never ceases, The name Netherlands (from the Dutch Nederland) means low land, and more than one­ third of Holland's land area of 12,530 square miles lies below sea level.

          Along the coast are dunes of sand-nature's dykes-thrown up by normal tides. The Dutch plant them with marram grass, which holds the sand together with its long, strong, creeping roots. Behind the dunes the Dutch built three dykes of close-packed stone, clay and earth on wooden and concrete piles. The dyke nearest the sea is called a "waker' Behind it lies a "dreamer" and behind that again a "sleeper" Some of the dykes are 200-300 feet high and many have a road or, some, a railway running along the top.

          In 1170 the North Sea swept into the country and formed the bay called the Zuyder Zee (South Sea). In 1421, another high tide flowed in to form the Holland’s Diep (Dutch Deep). The great spring tide of 1953 (two feet higher than any previously re­corded) smashed-the waker dykes, overflowed the dreamers and drowned about 1,900 people. About 50,000 were forced to flee from their homes.

          A famous Dutch story tells of a brave boy who stood for hours with his hand thrust into a hole in a dyke and so prevented the sea from rushing in and widening the breach in the wall.

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The manchineel tree is dangerous because its sap and fruit contain poison. Its other name is Hippomane, which comes from the Greek and means “causing horses to run mad”

      The tree is a member of the Euphorbiaceous family and grows in tropical America, producing a crop of acrid, bitter apple-like fruits which drop spontaneously and carpet the ground beneath it. The sap is white and highly caustic, so that a drop on the skin produces a burning sensation and raises a blister. It used to be believed by many that to sleep beneath the tree meant certain death. But the great 18th century naturalist Nicolas von jacquin “reposed under it for hours at a time without inconvenience”.

     The wood has often been used for furniture as it is beautifully patterened in brown and white. Before felling the tree by hand, workman light a fire round the trunk, so that the sap thickness and does not run down the handles of their axes.

               

                Mudskippers are small tropical fish of the eastern Atlantic, the Indian Ocean and the western Pacific from Australia to Japan. They live in estuaries with mudbanks and also in mangrove swamps. Their eyes protrude from their heads and can be moved independently of each other. When the mud is exposed by the ebbing of the tide the mudskippers come out of the water and hunt for crustaceans and other small invertebrates. They crawl and hop about rapidly with the help of their powerful muscular pectoral fins which they use as forelegs. Their gill openings are small and they can live on land for hours at a time, providing the air is humid.

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Laurel and holly trees have developed special kinds of leaves to seal the water inside them during the winter months.

    Both trees are evergreen .Instead of dropping all their leaves in Autumn, They shed old ones and grow new ones throughout the year. In winter the soil is too cold for the trees to draw water from it through their roots. Normal leaves would continue to transpire and to give off moisture until the trees died of drought. But the special leaves of the holly and laurel hold the water .their waxy surface and leathery texture make certain that the water is contained safely within the green tissues.

    Some of the holly leaves have a further modification. On the lower branches which are within reach of browsing animals, each leaf has a series of sharp point along its edge. The higher leaves have only a single point.

       Robin Hood lived in Sherwood Forest,  near Nottingham in the centre of England. In those 12th century days a vast region of open tracts, woodland glades and great oaks used to stretch for many miles from the city northwards. This region was called Sherwood Forest.

        Until the time of the Normans the forest was used for hunting by the people of that region, or shire, and thereby acquired its earlier name of shire wood .The common people’s right to hunt ceased when the Norman kings took over the forest for their own use. Strict laws were passed and special courts were set up to preserve them. 

         Whether Robin hood   and his merry band of followers, which included little john , friar tuck , will scarlet and maid Marian, ever existed is difficult to establish. Certainly by the end of the 12th century, with control of royal Sherwood in the hands of feudal barons, the common people deeply resented the harsh and oppressive rule under which they lived. The time was ripe for stories about a man who robbed the rich to feed the poor.

      The character of Robin Hood represented the ideals of the common people of the late middle ages. Ballads about his exploits have been preserved and may data from the14th and 15th centuries .in 1795 Joseph Ritson first published collection of these in book form.

     Over the years stories of the carefree folk –hero and band of happy followers, living an idyllic life in the woodland glades of the Plantagenet kings, have become the subject of many books.  

            Cowrie shells are widely distri­buted and possibly the favorites among shell collectors because of their polished enamel-like surfaces and their beautiful coloured pat­terns. The cowrie appears in all the warmer seas of the globe. But the great cowries, the tiger cowrie and the orange cowrie are natives of tropical regions. They crawl slowly, browsing on weeds, and are shy creatures remaining bidden during the day in crevices or under rocks.

            The best-known and most popular the tiger cowrie. The shell grows about four inches long and is covered with spots. It was used by 18th Century silversmiths to make shell snuff-boxes and in Italy for burnishing paper and ironing lace. The shells were often distributed in Europe by sailors and gypsies.

            Orange cowries at one time sold for large sums on the market. In Fiji and the New Hebrides in the Pacific they are still worn as badges of rank by the chiefs.

            The money cowrie is a small oval shell, flat and white under­neath-with thick yellowish-white edges and a pale lemon upper surface. It is found in enormous quantities in the Pacific, From the Moluccas eastward. Large for­tunes were at one time made by European traders who transported shells to the west coast of Africa and exchanged them for ivory, gold and slaves. A slave would be worth anything from 20,000 to 50,000 shells. In 1849 money cowries weighing 240 tons were imported into the English port of Liverpool.

            A man at Cuttack in Orissa India paid for the erection of his bungalow entirely in cowries. The building cost him £400 which in cowries amounted to 16,000,000 shells, the common method of handling the cowries was by threading them on a string, 40 cowries to one string.

            Among the cowries the rarest is Cypreaeleucedon. Only two known examples of this pale brown, creamy-spotted shell exist. One is in the British Museum, the other in the Harvard University Museum. More than 190 species of cowrie shell are known to col­lectors. Some species are used as charms against evil spirits.

            The green colour in grass-and in most other plants-comes from chloroplast within the cells, each of which contains four different colours or pigments. These are: chlorophyll a, which is the strongest and is blue-green; chlorophyll b. which is yellow green; xanthophylls, which are yellow; and carotene, which is orange and gives carrots their bright colour.

            Grass goes from light green in early spring to dark green and brown in summer and' autumn because the amount of each pig­ment changes, like the paint on a palette, to mix new colours.

            Kailash Satyarthi is a renowned Indian child rights activist and the winner of the Nobel Peace Prize in 2014.

            Satyarthi was born on 11th January 1954, in Vidisha, Madhya Pradesh. An electrical engineering graduate, Satyarthi, started a journal called ‘The Struggle Shall Continue’ in 1980 in order to create awareness about the problem of child labour.

            Satyarthi is the founder of the Bachpan Bachao Andolan, an organization dedicated towards the eradication of child labour and rehabilitation of the rescued former child workers. The organisation acts to protect the rights of more than 83,000 children from 144 countries. The success of this organisation led to the creation of the South Asian Coalition on Child Servitude (SACCS) in 1989. SACCS has till date liberated several thousands of child labourers working in different industries.

            His work is recognized through various national and international honours and awards including the Nobel Peace Prize of 2014, which he shared with Malala Yousafzai of Pakistan.

            Amartya Kumar Sen is the 1998 Nobel prize-winner in economics. He is a well-known economic theorist whose works link ethical questions with economic issues.

            Sen was born in Santiniketan, West Bengal. In 1956, at the age of 23, he was appointed as the Professor and head of the Economics Department at the Jadavpur University, Calcutta.

            After two years, he went to Cambridge University to pursue his Ph.D In 1959; he submitted his Ph.D thesis titled ‘the choice of techniques’, after which he was a visiting Professor at Massachusetts Institute of Technology.

            From 1961 to 1972, he was a Professor at the Delhi School of Economics, after which he was a Professor of Economics at the London School of Economics. Since 1972, had taught and worked in the United Kingdom and the United States.

            Sen has made contributions to welfare economics, social choice theory, economic and social justice and economic theories of famines.

            In 1999, he was awarded the Bharat Ratna, which is the highest civilian award in India.

            Mother Teresa was the founder of the Missionaries of Charity, dedicated to helping the poor. Considered one of the 20th Century’s greatest humanitarians, she was canonized as Saint Teresa of Calcutta in 2016.

            Mother Teresa was born Agnes Gonxha Bojaxhiu in Skopje, Macedonia, on 26th August 1910. But she later moved to India, where she lived for most of her life.

            The Missionaries of Charity came into being on 7th October 1950, in Calcutta, with the Vatican decree recognizing the diocesan congregation. Mother Teresa proceeded with the aim to care for the hungry, the naked, the homeless, the crippled, the blind, the lepers, and all those people who feel unwanted, unloved, uncared. It had over 4,500 sisters, and became active in 133 countries by 2012.

            She received the Padma Shree in 1962 and the Bharat Ratna in 1980. She was awarded the Ramon Magsaysay Award for Peace and International Understanding in 1962.

            Mother Teresa accepted the Nobel Peace Prize in 1979.