Current Affairs 7th Class

  Weather And Climate   In the previous chapter you learned about the atmosphere. You know that it keeps on changing every moment and is never static. Any change in the atmosphere gets reflected in the weather of a place. In this chapter, you will learn about the elements of weather and the factors that affect these elements.   WEATHER AND CLIMATE   We have learned that the temperature varies in each layer of the atmosphere. However, the temperature of the earth is mostly related and affected by the lowest layer of the atmosphere, that is the 'troposphere'. In this layer, all th phenomenon of the weather occurs. Thus, this is most active, effective and volatile layer. Also, the weather in turn is affected by the amount of moisture, air pressure, temperature and movement of air. Whenever these features of the atmosphere change, it results in the change of weather conditions. Weather is the condition of the atmosphere at a particular place over a short period of time. Climate, on the other hand, is the average weather conditions over a longer period of time, say over a period of 20 to 30 years.   ELEMENTS OF WEATHER AND CLIMATE   Atmospheric temperature, air pressure and precipitation are different aspects that control weather conditions. Thus the various elements of weather are?temperature, air pressure, wind, cloud, moisture, rain, etc.   The elements of weather can be measured and recorded at a weather station. People who study weather are called meteorologists. Weather reports are prepared by the meteorological department. They use various instruments such as barometers, thermometers, wind vanes and radars, to gain information about the weather.   Daily readings of instruments recording the various elements of weather are taken every 24 hours. Satellites hovering over the earth send  

Weather	Climate
1. Weather refers to the general atmosphere conditions of a day.                          2. There can be multiple weather conditions in a day. 3. It is the average record of atmospheric temperature, atmospheric pressure and rainfall over a small area on a daily basis.  4. Weather is described as hot, cold, sunny, cloudy, windy, calm, wet and dry.	1. Climate is the total sum of weather conditions and variations over a long period of time. 2. Climate conditions take years to change. 3. It is the aggregate of atmospheric temperature, atmospheric pressure and rainfall over a large area over 30 years or more. 4. Climate is described as equable, extreme, tropical and temperate.

            Various weather instruments     Activity Read the given weather report from the newspaper. What are the different more...

  The Atmosphere - A Blanket of Air   The earth is a unique planet, as it is the only planet known to us that supports life in the Solar System There are many reasons why life exists on the earth and one of the reasons is the presence of air Hold your breath tor some time. How do you feel? You feel suffocated. Living beings breathe in air to survive the earth is surrounded by a thick blanket of air called the atmosphere.   If you look down from a spacecraft, you will see the atmosphere as a blue haze that envelopes our planet.     The earth's atmosphere acts like a filter; it allows sunlight to reach us but prevents the dangerous ultraviolet rays of the Sun from reaching us. The atmosphere consists of gases, dust particles and water vapour. The right composition of gases in air also makes life possible here. Thus, the atmosphere provides the necessary conditions for all forms of life to thrive on earth.   COMPOSITION OF THE ATMOSPHERE     Air is a mixture of several gases. The most abundant gas in the atmosphere is nitrogen, followed by oxygen. Carbon dioxide is present in small amount. As seen in the figure given above, air contains about 78 per cent nitrogen and 21 per cent oxygen. The remaining 1 per cent consists of carbon dioxide (0.03 per cent) and traces of other gases like argon, neon, helium, hydrogen, krypton, xenon and methane. Besides these gases, there are water vapour, dust particles, salt particles, etc., in the atmosphere. As we move towards space, the atmosphere becomes thinner and gradually merges with space. All the gases present in air are important to us. Now let us study the constituents of air.   Nitrogen?this is the most abundant gas in the air. Nitrogen neither burns nor helps in burning. Nitrogen is an inactive gas, therefore, it is used in packaged food like chips. This allows the packaged food to remain fresh. Nitrogen is required by plants for growth. Bacteria converts the nitrogen in the atmosphere in forms usable for plants. Recall the nitrogen cycle you read in your science class.   Oxygen-as you know, most of the living beings require oxygen present in air for respiration. Oxygen supports burning. An adequate supply of oxygen is necessary to burn fuels. Oxygen is a heavy gas and most of it is found in the lower layers of the atmosphere. Mountaineers and divers carry oxygen cylinders to more...

  Our Ever Changing Earth   After the condolence meeting for the victims of the Nepal earthquake, Meghna and Kartik were discussing as to why certain areas around the earth are prone to earthquakes, volcanic eruptions and tsunamis. Both of them realised that there is one person who would have the answers and that would be their Geography teacher. She explained to them at length.   MOVEMENTS OF EARTH SURFACE   In the previous chapter, we have learnt that the lithospheric plates are broken like an eggshell and these tectonic plates float on the molten magma in the asthenosphere. Movements of these plates is as slow as few millimetres in a year. Still it changes the earth's surface. But this is not the only reason, there are external forces as well, that lead to changes on the earth's surface. Forces which affect the earth's surface from its interior are called Endogenic forces, and which affect the earth's surface from outside are called Exogenic forces.   CAUSES OF MOVEMENT   You must be surprised and thinking that how such a small scale movement can change our lithosphere to such a large extent? And what actually causes this movement? It has been discussed and mentioned earlier that core of our earth is not solid and even the upper mantle is semi-solid or semi-molten. As we go deeper, temperature increases with the increasing depth. If it is around 1600°C At asthenosphere, it is around 6000°C in the core. The heat from the core generates the convectional current in the mantle. Rising current of heated magma reaches the top, cools down again to become heavy and sinks. This cycle of moving up and sinking down of magma causes, movements in slow motion in the tectonic plates; that float on the asthenosphere.   As we mentioned in the previous chapter that there are six major and twenty minor plates on     Convection is a process of heat transfer of liquids and air. Heated air or fluid moves up. As they reach up to the surface, they start loosing their heat and cool down. Then they sink back from the corners and complete the circular motion. A similar process is found in the middle layer of the mantle, due to which magma moves upward and causes movement of the plates.   The crust. Although these plates are made up of solid rocks but they float on the molten magma of asthenosphere as they are lighter in density in comparison to the mantle. Distribution more...

  Inside Our Earth-Rocks and Minerals   Have you ever dug a hole in your backyard? How deep could you dig? One metre? Two metres? Or perhaps three metres if you really work hard. The deepest mines on the earth are only about 3.9 km deep. Some geologists have dug the earth as deep as 11 km beneath its surface. However, this is just scratching the surface. The earth is approximately 6,400 km from the surface to the centre. Let us learn and understand about the interior of the earth in this chapter.   Our earth is dynamic. It is always on the move (rotating and revolving) and constantly changing internally and externally. To know how changes take place on the earth's surface, we need to study the structure of the earth. A detailed study of the interior of the earth has been done by geologists.   INTERIOR OF THE EARTH   There are multiple sections or layers of the earth. Their classification is based on their composition, according to which the earth has three layers namely; the Crust, the Mantle and the Core. The Geologists named these three layers as the Lithosphere, Pyrosphere and Barysphere. These layers have different constituent minerals, density and other features.     CRUST   The crust is the outermost and the thinnest layer of the earth. It is usually 35-80 km and sometimes 100 km thick. This part is known as the Lithosphere. The crust is divided into two layers:   (a)  The lower layer of the crust is the oceanic crust. It consists of darker, denser basaltic rocks. Rocks of the oceanic crust contain silicon (Si) and magnesium (Mg). Therefore, the oceanic crust is also called Sima. It is more or less a continuous layer and forms both the ocean floors and the base of the continents.   Interior of the earth   (b)  The upper layer of the crust is called the continental crust. It consists mainly of granite rocks which are of lighter colour and density. The granite rocks are more acidic. The upper crust is rich in silicon (Si) and aluminium (Al). For this reason, the upper or continental crust is also called Sial. It is a discontinuous layer which forms the continents.   MANTLE   more...

  Understanding The Environment   Pranav was on vacation with INS family at a countryside resort. He was amazed to see such a clear blue sky and changing shapes of clouds in the day time and the sky full of stars at night. At the same time Radha, a village girl was astonished to see high-rise buildings, wide roads, flyovers and large number of people; during her first visit to a big city. What surprised Pranav and Radha are all the components of an environment? The environment is what surrounds us. Each and every place has a different kind of environment; be it a city. Village, school, office or even a classroom.     ENVIRONMENT   The environment is something which you all are very familiar with. It is everything that makes up our surroundings and affects our life. The air, the water, the plants and the animals along with all other man-made features, make up our environment. Thus, the environment may refer to:   ·   The natural environment that includes all things, both living and non-living that occur naturally on the earth, and ·   The human environment that includes built-up areas like buildings, roads, technology, social and cultural factors, like family and society. In this chapter, you will learn how natural features and humans interact with one another and how their interrelationship affects our environment.   PHYSICAL OR NATURAL ENVIRONMENT   The physical or natural environment encompasses all living and non-living things occurring naturally. The natural environment has two components-biotic and abiotic. All plants and animals in the surroundings constitute the biotic component. The non-living things-air, temperature, water, light and soil-form the abiotic component. Both biotic and abiotic factors have influence on an organism. Again, the abiotic factors influence biotic factors and vice-versa. This is called interdependence.   The Physical Environment   Components of the physical environment The land, the oceans, the seas and the atmosphere around us, support our life and comprise our natural environment. There are four realms or spheres of the earth:   1.  The sphere of land is known as the lithosphere where lithos means rock. 2.  The sphere of water is known as the hydrosphere where hydros means water. 3.  more...

  Political Formation in Eighteenth Century India   The Mughal Empire was at its zenith under Aurangzeb. After his death, the empire weakened and many new regional powers emerged and gained strength before the establishment of British.   The great Mughal Empire rapidly declined after the death of Aurangzeb. The Indian subcontinent witnessed major political changes in the 18th century. The period between Aurangzeb's death and the establishment of the British Empire in India was a time when many independent states rose to power. The subcontinent was fragmented and ruled by different rulers. In this final chapter, we shall study about these rulers and the political scenario of the subcontinent just before the British came to power. The 18th century also marked the end of the medieval period in India.   CRISIS IN MUGHAL EMPIRE AND LATER MUGHALS   Aurangzeb died in 1707. Soon after his death, the disintegration of the Great Mughal Empire began. There were a series of inconsequential1 kings known as the Later Mughals. After Aurangzeb's death, a war of succession broke out and finally, Bahadur Shah I ascended the throne. It was difficult for him to hold the large empire together which was already in a state of collapse. Also, the Sikhs rose up in revolt during his reign. He tried to implement peace. His reign was short and lasted till 1712.   History Reveals When Aurangzeb died, he left numerous successors that included sons, grandsons and great grandsons.   Bahadur Shah's sons fought for the throne and the survivor Jahandar Shah ascended the throne in 1712. He was lazy and neglected his duties and the power was in the hands of his Prime Minister Zulfikar Khan. Jahandar Shah was defeated and killed by Farruksiyar who ascended the throne with the help of the Sayyid brothers who were very powerful nobles. However, he was merely a puppet in their hands and was later killed by them.   Q. The Sayyid brothers were also called 'Kingmakers'. why ?   Muhammad Shah came to the throne in 1719. He got rid of the Sayyid brothers. It was during his reign that many provinces like Deccan, Bengal and Awadh became independent.   Bahadur Shah Zafar was an emperor in name only. His empire was limited to the Red fort. After the Revolt of 1857, the British exiled him to Burma where he died in 1862. His sons were executed and with that the glorious Mughal Empire came to an end.   more...

  The Making of Regional Cultures   The culture comprises language, literature, music, dance, traditions and different forms of art. The language plays a very important part in shaping a particular culture and developing rich volume of literature. We Indians speak more than a hundred languages. The Indian culture is strikingly different in each region whether it is north, south, east or west. In this chapter, we will see how regional cultures developed in India over the period of time and how regional literature is used to reconstruct history.   The culture of each region is distinct and has evolved over time. Also, it continues to change through contact with other cultures. It is the end result of fusion of local traditions and ideas from other cultures. Distinctive styles developed as a result of this fusion during the medieval period.   REGIONAL INFLUENCES ON CULTURE   REGIONAL LANGUAGES   During the medieval period, there was development of Persian, Sanskrit, Urdu and many regional languages. Regional languages flourished and a large volume of literary work was done in these languages. These languages developed due to the patronage extended by local rulers.   Malayalam There is evidence to suggest that Malayalam was one of the earliest languages to be used in court records. The Chera kingdom of Mahodayapuram existed in the region of present day Kerala. The rulers used Malayalam as the official language. With the patronage it received, it became an established language of the region. Much literature was written in this language since the 12th century. However, the stories written in Malayalam were of Sanskrit origin. A famous text Lilatilakam dates back to the 14th century. It is written in Manipravalam, a literary style which was a mixture of Tamil and Sanskrit. Manipravalam literally means ruby and coral, where Mani means 'ruby' in Tamil while Praualam means 'coral' in Sanskrit.   Sanskrit The Persian speaking rulers spread Persian language. Though Persian gained importance, Sanskrit continued to co-exist. A centre for Sanskrit was opened in Mithila (Bihar). The kings of Vijayanagar and Rajput rulers also used Sanskrit. Important Sanskrit works of this period are Prithvirajavijaya and Rajatarangini. Many Sanskrit works were translated into Persian.   Urdu Urdu came into existence during this period. Amir Khusrau experimented with poetry in a language that was a combination of Persian and Hindi. This was the origin of Urdu. Urdu is a Turkish word meaning 'army' or 'camp'. He called this Hindawi. In the Deccan, it was called Dakhini. It developed under Bahamani rule and was used in the Golconda and Bijapurkingdoms. Urdu was used in the Mughal court more...

  Devotional Paths to the Divine     The medieval period witnessed major changes in the area of faith and religion. Due to the Turkish invasion, religions in India came into contact with Islam. It influenced them immensely. Two new religious movements-Bhakti and Sufi Movements-emerged in India during the period from the 7th to the 9th centuries.   During the medieval period, many religions existed in India. Different Gods wereworshipped. People believed in the cycle of birth and rebirth. A person's deeds determined his next birth. The society was caste based with the brahmanas at the top of the social hierarchy. The lower castes were badly treated and looked down upon. A person's caste was determined by birth. As the caste system was not acceptable to all, the lower castes turned towards Jainism and Buddhism. These religions welcomed people of all castes and believed in equality and brotherhood.   According to the Bhagavad Gita, there is a supreme God who should be loved and worshipped with devotion. This appealed to the common people. People from all castes began worshipping Durga, Vishnu and Shiva by performing numerous ceremonies and rituals. Gradually, many people joined the Bhakti Movement and it spread far and wide.   THE BHAKTI MOVEMENT   The Bhakti Movement emphasised on devotion to God. It taught the path of love and devotion as opposed to the path of rituals. The Bhakti saints were simple people from all walks of life. Some of them were from the lower castes. Some of their common teachings are:   ·   According to them there is one God who has to be worshipped with love and devotion. ·   There is no idol, tree or animal worship and elaborate rituals and sacrifices. ·   They were against social evils like child marriage and sati. ·   They were against the caste system. They believed that all were equal in the eyes of God. ·   They stressed on Hindu-Muslim unity. ·   Emphasis was laid on virtues like honesty, truth, kindness and charity. A combination of factors led to the growth of the Bhakti Movement. ·   The social and political conditions at that time led the Hindus to choose the path of Bhakti. ·   The ill-treatment imparted to the lower castes drive them to join the Bhakti Movement which stressed o equality. ·     Tribes, Nomads and Settled Communities   In the medieval period when new towns were developing, new trade relations were forming and handicrafts and other craftsmanship were scaling new heights; there were groups of people who were unaware. Unaffected and untouched by these changes. They were the original inhabitants or remotely settled adivasis. Whom we call "tribe". The Tribal societies spread over a large area and play an important role in the study of our past.   BEYOND BIG CITIES?TRIBAL SOCIETIES   During the medieval period, society was divided according to the rules of the Varna. The Brahmanas occupied the dominant position and the Shudras   A Kutia Konth Women   Were at the bottom rung of the social hierarchy. At the same time, there were some societies that were egalitarian. They did not follow the Varna system and there was equality. No caste or caste division existed. They did not follow the rules and customs of the Brahmanas. These were the   A Few tribal Women performing traditional rituals   'Tribals of the subcontinent. The Tribals families were closely knit. Members within a tribe were united by strong kinship bonds. The tribals usually lived in remote areas. They dwelled nearby a mountain range or forest where no sign of modern culture could be seen. They had a strong sense of unity and were completely oblivious of the outside world. The tribals made use of the forest resources for a living. Some were hunter-gatherers while some were herders.   There were nomads also who moved from one place to another for their livelihood. Some practiced settled or shifting agriculture. We do not have enough information about the tribal people. This is because the tribals being illiterate did not keep any written records. Also, mostly they did not welcome outsiders. Their customs and traditions are passed down to the next generations by oral tradition.   History Reveals   The north-east of India is home to many tribal communities. They are found in Nagaland, Arunachal Pradesh, Manipur, Assam and Odisha.   WHO WERE TRIBAL PEOPLE?   Nomads are a group of people who travel from place to place for livelihood. They moved according to seasonal changes along with their animals. Their main occupation was herding cattle and sheep. They exchanged animal products for the things they required. There were many nomadic tribes in India. Some of them are Jats, Gaddis, Banjaras and Gujjars. more...

  Towns, Traders and Craftsmen   India has been a prosperous country since ancient times and tills continued during the medieval period. Also, there was an upsurge in the number of towns and cities. This was probably due to the excellent administration and policies of the emperors.   The medieval period in India witnessed the growth of many towns and cities. During this period, older cities were revived and new ones were established. How did this come about?   TOWNS IN MEDIEVAL PERIOD   Many small towns grew out of villages. They had markets where people came to sell their goods. The market was called mandi. There were also shops lined in streets. These were called haats. Foodgrains, sugar, jaggery, oil, butter and cloth, etc were bought and sold here. Artisans like metalsmiths, potters and masons occupied different streets. There were local traders while some came from distant places to trade. The traders and artisans were taxed by the local zamindars or the local temple. Some taxes were collected in cash while others were paid in kind.   History Reveals According to Abul Fazi, in 1594 there were 2837 towns of which 180 were named as larger cities.   TYPES OF TOWNS   The towns that developed were of the following kinds: a)  Administrative or Capital towns b)  Commercial and Port towns c)  Religious or Temple towns d)  Founded towns   Changing Fortunes of Cities Some towns prospered and became major commercial centres whereas others suffered a setback. Masulipatnam suffered a setback as European traders set up trading centres at Madras, Bombay and Calcutta. Many towns which were the centres of textile production also declined because their products faced competition from the cheap machine made goods that European traders poured into India. Murshidabad was one such town.  Some towns served more than one function. For example, a town could be both administrative as well as temple town.   Administrative or Capital Towns Some towns developed because the rulers and their families lived there. The ministers, nobles, soldiers and administrative heads of the kingdom, merchants/ craftsmen etc. also lived in these towns. Thus, these towns had many palaces, market places and good roads. Many of these towns were protected by high walls. Some of th important capital towns more...