Chapter 1 The Universe And Our Solar System: The Sun, The Stars And The Sky Introduction :

The earth, on which we live, is not alone in space. From our childhood we see the sun shines during the day and at night we see the moon, numerous twinkling stars and other luminous bodies scattered in the sky.

They are called heavenly bodies or celestial bodies. A celestial or heavenly body has been evolved by nature and exists in outer space. Let us examine the groupings of different celestial bodies in space.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

They may be grouped as follows :

1. Galaxies.
2. Nebulae.
3. Stars.
4. Planets.
5. Satellites.
6. Asteroids or Planetoids.
7. Comets and
8. Meteors.

Space :

Space is an area of unspecified size. It is a continuous unlimited area or expanse which may or may not contain objects etc. Space is not so empty as it was once thought to be.

There are millions of galaxies and other heavenly bodies and each is separated from the others by vast reaches of space.

Sky :

The sky is the region of the atmosphere and outer space seen from the earth.

The Universe:

The word ‘universe’ is derived from the Latin ‘Universum’ which means ‘(things) combined into one, whole’. The universe is the whole of creation.

Philosophically, it may be defined as everything that exists or appears to exist, known and unknown, material and non-material. In a more restricted sense, ‘Universe’ refers to all systems of astronomical bodies-Galaxies, Stars, Planets etc.

in the infinite ocean of space. The limitless space of infinite dimensions with its contents is generally referred to as the Universe. The Universe comprises millions and millions of galaxies or star systems.

Yet we do not know about the dimensions of the Universe or the exact number of galaxies. So, our knowledge about the Universe is far from complete.

Black hole :

Black hole is a region of space from which nothing, not even light, can escape. Its force or gravity is much more powerful than any other normal star in the Universe.’

Origin And Expanse Of The Universe :

The most widely accepted theory about the origin of the Universe is the ‘Big Bang’ theory. Many astronomers believe that the Universe began life in a single momentous event.

This was an incredibly hot, dense explosion called the ‘Big Bang’ which took place about 15 billion years ago. During this explosion, all matter, energy, space-and-time itself were created.

In the first few millionths of n second, the particles that makeup atoms, the building blocks of all matter, were formed. It took about 100,000 years for the first atoms, those of the gases hydrogen and helium, to come together.

By the time, the scary heat of the ‘Big Bang’ had cooled, space has expanded and the gases began to spread out. Gradually, however, gravity drew the gases together leaving vast regions of empty space in between. Our own Earth, along with our Solar system, is a product of a stellar explosion almost five billion years ago.

How Vast Is The Universe ?/Vastness Of The Universe :

The Universe is unimaginably vast. It is billions upon billions of kilometres wide. Distance in the Universe is so great that we have to use a special measure to record them.

This is the light year, or the distance that light, which moves at a speed of about 300,000 kilometres per second, travels in one year (i.e. about 9,460,528,405,000 kilometres).

The nearest star to earth (after the Sun), Proxima Centauri is 4-2 light years away. The most distant objects we know in the Universe are more than 13 billion light years away from Earth.

The Universe is indeed very vast in size. Our Earth may thus be considered to be a sand particle in the desert of the star-studded Universe.

What is Galaxy?

Galaxy:

A galaxy is an archipelago (group of islands) of billion of stars that are held together by the force of gravity. The word ‘galaxy’ itself comes from the Greek word ‘galactic’ which means milk.

This is because galaxies were looked like milky or cloudy areas in the sky before telescopes were powerful. The Universe contains millions of galaxies.

There Are Three Main Types Of Galaxies, According To Thin Shape

1. Elliptical, which are oval-shaped,
2. Spiral, which have arms spiralling outwards from a central bulge, and
3. Irregular which have no obvious shape. The Milky Way is a spiral galaxy.

The Milky Way is only a part of the galaxy. The sun from which we receive light and energy belongs to a galaxy, also known as the ‘Milky Way’, (in India it is known as ‘Akash Ganga’).

The Milky way is made up of about 100,000 mi sn stars, along with clouds of gas and dust. The Milky way has the shape of a disc. we car. identify the Milky Way on a clear moonless night. It looks like a white belt of shining tiny stars across the sky.

What Is Nebula?

Nebula:

A Nebula is a cloud of dust and gas inside a galaxy from which stars are born. V.ore than one Nebula is called ‘Nebulae’. Nebulae represent the building blocks for stars, galaxies and planets in the Universe.

Nebulae become visible if the gas glows, or if the cloud reflects starlight and obscures the light from more distant objects. Emission nebulae are hot, discrete clouds of primarily ionized hydrogen that glow with their own light.

Reflection nebulae emit a bluish glow by reflecting the scattered light of nearby stars. Absorption nebulae, or dark nebulae, comprise dense clouds of gas and dust. They appear as silhouettes against the light of brighter objects.

The Stars :

A star is a luminous body of hot, glowing gas mostly hydrogen and helium that are born in a Nebula. Stars generate light and release energy from nuclear fusion reactions in their core.

They vary enormously in size, mass and temperature. The colour of a star is determined by its temperature. The hottest star is blue and the coolest is red.

Stars may look like tiny points of light in the night sky but many stars are incredibly big. Betelgeuse, in the constellation of Orion, is 800 times the size of the sun, our local star.

Stars seem to twinkle in the sky because we see them through the layers of the earth’s atmosphere. As light passes through these layers, it is distorted so that the amount we actually see changes constantly.

The stars nearest the horizon appear to twinkle the most because the light is passing through a greater depth of atmosphere. Stars do not twinkle when viewed from space, which is why telescopes in space.

Constellation :

Constellation is a group of stars that forms an imaginary pattern representing an object, animal or person as seen from the Earth. Cassiopeia, Orion, Ursa Major, Ursa Minor etc. are a few of the well-known constellations.

Cassiopeia :

‘Cassiopeia’ is named after queen Cassiopeia of Greek mythology. It is seen in the northern sky. Cassiopeia forms an ‘M’/’W’-shape by its five bright stars.

Orion :

‘It looks like a gallant hunter. It is one of the most beautiful of all constellations. In Bengali, it is known as ‘Kalpurush’. It is seen in the southwestern sky.

‘Ursa Sky Major :

Ursa Major is a group of seven bright stars. The meaning of this name is the ‘great bear’. In India, it is known as ‘Saptarshi Mondal’. These stars form a pattern known as the ‘Big-Dipper’ in the U.S.A. and the ‘plough’ in the U.K, These stars are usually seen in the northern sky in most of the northern hemisphere.

Planets :

A planet Is a heavenly body that orbits a star while rotating on us axis. He word ‘planet’ comes from the Greek word ‘planets’. it means ‘wanderer and were so named as they seemed to move about or wander in the sky.

Planet dees not tad-late Its own light, but reflects the light from the star. While stars appear to twinkle, planets shine with a steady light because planets lie at comparatively smaller distances while the planets are rotating their own axis, they also revolve the sun (nearly star).

Characteristics :

1. A planet is much smaller in size than a star,
2. Planets have no light of their own.
3. Planets are illuminated by light from the? star and also reflects the light from the star,
4. Planets may be solid or gaseous,
5. AH planets do not have satellites,
6. Planets revolved around the stars.

Difference Between Star And Planets :

Stars	Planets
1.    Stars are huge heavenly bodies of hot, glowing gas that are born In nebulae.	1.    Planets are smaller heavenly bodies that are cold and solid.
2.    Stars have their own light and heat.	2.    Planets arc lighted and heated by the sun.
3.    Stars are very large.	3.    Planets are smaller than stars.
4.  Stars are twinkling.	4. Planets do not twinkle because it just reflects the light received from pi a star.
5. Generally, stars are stations!y,	5. Planets are moving around the stars.
6. Stars were originated before the origins of planets.	6. Planets were originated after the origin of the star.
7. A star holds the central position among the other planets.	7. Planets revolve around a def. nte s’.a in a definite path to; hit) and direction.
8.  A star has planets revolving around it	8. A planet has satellites revolving around it.

Dwarf Planet:

A dwarf planet is a smaller celestial round object that orbits the sun. Pluto, Ceres, Erls ate examples of dwarf planets

Characteristics :

1. It moves around the sun.
2. Its gravitational pull is weak
3. It has debris within the orbit
4. It is small
5. It is not a satellite

Difference Between Planets And Dwarf Planets.

Planets	Dwarf planets
1.    A planet is a celestial body which moves around the sun.	1.    A dwarf planet is a smaller celestial round object that orbits the sun
2.    It has sufficient mass for its self-gravity to overcome rigid body forces.	2.    Its gravitational pull Is weak.
3.    Its orbit is not round.	3.  Its orbit Is nearly round.
4.    It has cleared neighbourhoods around its orbit.	4.    It has debris within its orbit

Satellites :

The word satellite means ‘attendant’ or ‘follower’. Satellites are small spherical heavenly bodies that rotate on their axis and revolve around the respective planets. All planets do not have satellites.

The earth has only one natural satellite. The name of the earth’s satellite is ‘Mono’ Mercury and Venus have no satellites like planets satellites also have no light and heat of their own. Sunrays are reflected from satellites. So they look bright.

Differences between Planets and Satellites :

Planets	Satellites
1.    Planets are much bigger than satellites.	1.    Satellites are much smaller than planets.
2.    Planets revolve around the stars.	2.    Satellites revolved around the planets.
3.    Planets are far from the stars.	3.    Satellites are closer to the planets than the stars.
4. Life may exist in any planet. Our earth Is the only planet where plants and animals live.	4.    There is no trace of life in satellites.

Comets :

A comet is a luminous mass of cosmic dust or nebulous matter having an elongated tail and moving in a highly elliptical orbit around the sun.

Comets are such heavenly bodies which of ten exist in the ‘Kuiper Belt’ at the edge of or beyond the solar system. They are different from stars and other heavenly bodies.

Characteristics:

Comets are small bodies with a core of dust and frozen gases.

1. They have a head called ‘coma’ and a long tail. Many comets do not have tails. A well-developed comet has a tail that always turns away from the sun. The tails are often bright and millions of km long. The tail is made of glowing gas and dust.
2. Most of the time comets remain outside the solar systems and cannot be seen.
3. Comets move around the sun in regular orbits and their path is elongated and elliptical.
4. Comets take from hundreds to thousands of years to complete one revolution around the sun.
5. The comets eventually die.

Halley’s comet discovered in 168z, by Edmund Halley is a periodical comet. It is seen at intervals of 76 years. It was seen in 1910 and 1986. There are many Non¬periodical comets. They are very rare and not sighted at regular intervals.

Meteors/Meteoroids:

While looking at the night sky sometimes one may notice a bright light moving with a considerable velocity which disappears immediately. Some call it a ‘shooting star’, some say ‘a star is falling.

‘ In fact, these are mostly meteors or meteoroids. Meteoroids are small chunks of stone or some of which are fragments of asteroids or comets. If a meteoroid enters the Earth’s atmosphere, from outer space, it is heated by friction and appears as a glowing streak of light called a ‘meteor’.

They are attracted by the Earth’s gravity and rapidly pass near the earth, they are seen as rapidly moving bright objects in the sky lasting for a few seconds. So, they are also called ‘shocking stars’. ‘Meteor showers’ occur when the earth passes through the trail of dust particles left by a comet. Most meteors burn up in the atmosphere.

The few that are large enough to reach the earth’s surface as a large boulders. These are termed as ‘meteorites’. A large, meteor crater, of diameter of 12000 metres is known to exist in Arizona State of the United States.

Meteors are known to have fallen on other planets and satellites also, resulting in the formation of craters.

Asteroids :

Asteroids are small, mostly rocky, irregular-shaped bodies, orbiting the sun. Asteroids range in size from tiny specks to about 1000 kilometres in diameter.

They are sometimes known as ‘minor planets’ or ‘Planetoids’. These are found between the orbits of Mars and Jupiter. Asteroids move around the sun in the same direction as other planets, e.g.-Harmes (32 km of diameter).

There are also some known asteroids Juno (diameter 190 km), Vesta (diameter 390 km) and Pollas (diameter 490 km). The asteroids resemble the planets in all respects except their small and irregular size.

The Solar System

The Solar system consists of the Sun, together with the planets, their moons (natural satellites), comets, asteroids, meteoroids, and a mass of gas and dust that circle around it.

The Latin equivalent of ‘sun’ is ‘sol’; that is why it is called ‘solar system’. If planet Earth is our home, then the solar system is our neighbourhood. The Earth is a member planet of our Solar system and our solar system is a small part of the systems of the stars collectively known as ‘galaxy’.

It is known as a system because all the heavenly bodies of the Solar family are bound by independent relations. The Sun is the nucleus of the Solar system around which other celestial bodies as members of the system revolve along their respective orbits. The Solar system has a diameter of about 11790 million km.

Its planets can be easily grouped into two divisions.

(1) Inner Planets :

These planets (Mercury, Earth, Venus, and Mars) are small in size but have high densities. They are also known as ‘Terrestrial Planets’.

(2) Outer Planets :

These planets (Jupiter, Saturn, Uranus, Neptune) are big in size but have low densities. They are also known as Major planets or Giant planets. It should be noted that the solar family occupies a very small part of the Universe.

How The Solar System Is Formed :

Formation Of Solar System:

Scientists believe that about 4.6 billion years ago there was no sun, no moon and no solar system at all. But there was only clouds of dust and gases in space.

These gases, main hydrogen and fly partly helium together with dust particles in space forming a cosmic cloud. When this cloud is disturbed by different cosmic factors then it is squeezed.

Eventually, it collapsed creating a flat spinning disc of gas and dust. The disc gradually formed a Nebula. French Scientist Laplas thought that parts of a huge Nebula separated and cooled to give birth of these planets.

According to Russian scientist Auto Smith gases and dust particles around the Sun combined to form these planets. According to Friedman of Russia and Mublc (USA), about 15 billion years back by the explosion of a giant heavenly body huge stars were formed which in turn exploded to form small stars and these planets.

Recently British scientist Stephen blockings has also supported this theory.

He Members Of Our Own Solar System Or Solar Family :

The Sun is the head of the solar family and our Earth is the member planet of this family. The members of this family are the Sun, eight planets (including our earth), and their satellites, three dwarf planets and thousands of asteroids, meteors and comets.

The sun holds the members of its family of planets and others near it by the pull of its own gravity. All the planets and asteroids (planetoids) move around the Sun in fixed elliptical paths called Orbits.

99.87% by volume of the total matter of the solar family is connected within the sun.

The Sun :

The Sun is a very ordinary star in the Universe but the head of the solar family. It appears bigger and brighter as it is closer to the earth than all the other stars. The Sun is located at the centre of the solar family and about 15 crore km away from our Earth. But actually, Sun is 13 lakh times bigger than the Earth.

It is a gigantic ball of gases composed mainly of hydrogen and helium. The temperature at the core or centre of the Sun is around 1.4 million°C. Its surface temperature is about 6000°C. From its central core to the surface.

There are four distinctive layers, they are—

1. Core of the Sun.
2. Photosphere.
3. Chromosphere and
4. Corona.

 

1. Core of the Sun :

The hottest central part of the Sun is known as the core which is made of hydrogen and helium in a burning state.

2. Photosphere :

The visible yellow face of the Sun is called the photosphere or the sphere of light. Here the temperature is about 6000°C. Dark patches called ‘Sunspots’ are sometimes seen in the photosphere.

These are the cooler spots where the temperature is about 4500°C. The rays and heat we get from the sun, radiating from it.

3. Chromosphere:

It lies surrounding the photosphere. It is pink in colour. Thousands of big flames are radiating in every second in this part. The flames of the chromosphere are called ‘prominences’.

4 Corona:

Behind the chromosphere lies the corona. A bright gaseous belt above the photosphere is known as a corona. It is the uppermost layer of the sun. A regular observation shows that the Sun rotates on its axis.

The time for one complete rotation of the Sun is equal to about 25 days. The Sun also revolves around the centre of the Milky Way (our own galaxy) once in 200 million years. In India, it is known as ‘Akash Ganga’.

Planets Of Our Solar System :

There are eight big planets in the solar family. According to distance from the Sun, these are-

1. Mercury.
2. Venus.
3. Earth.
4. Mars.
5. Jupiter.
6. Saturn.
7. Uranus and
8. Neptune.

There are also three dwarf planets. These are-

1. Pluto
2. Ceres and
3. Eris.

Mercury :

Mercury is the nearest or closest planet to the Sun. God of commerce and also a messenger for other Gods. Mercury was the Roman. Mercury was named after the speedy messenger of the gods because it is seemed to move more quickly than the other known planets.

It is slightly larger than our moon. It has no atmosphere or hydrosphere. It also has no satellite. Mercury’s surface is bare, rocky and covered with craters. So, it looks quite similar to that of our moon. It has great extremes of temperature.

Venus:

Venus is a fascinating planet. It is the brightest planet of the Solar system. Often it will be near the moon in the sky, making its identification easy. Venus is named for the Roman goddess of love. It is the only planet in the solar system with a female name. In many ways, Venus is nearly earth’s twin.

Considering the value of Earth as 1, Venus has 0.82 times of mass, 0.95 times the radius and 0.94 times the density of the Earth. Therefore Venus is called ‘Earth’s Sister twin’.

Venus is different from Earth in many respects. Venus rotates from east to west. This means that the Sun would appear to rise in the west and set in the east.

It has a thicker and denser atmosphere than the Earth. Venus is probably the hottest planet of the Solar system. The surface temperature is estimated at about 500°C on the sunlit side.

One of the reasons for the high temperature is that the planet rotates extremely slowly. A second reason is the effect of the thick atmosphere around the planet. So, there is no trace of life on Venus.

Venus is visible in the eastern part of the sky early in the morning, then it is called ‘Morning Star’ and in the evening when it is visible in the western part of the sky after sunset is called ‘Evening Star’.

The Earth :

The Earth is the third planet from the Sun and it is the fifth largest planet of the Solar system. The Earth has an atmosphere which is rich in nitrogen and oxygen.

There is an abundance of water on the Earth. No other planet has such a large amount of water. The Earth has optimum conditions for the growth and evolution of various forms of life.

The Earth has two motions—rotation and revolution. It causes day and night and changes of seasons.

The Mars :

Mars is fourth in distance from the Sun and seventh in size. In ancient Rome, Mars was initially a god of fertility and agriculture, but later he also became the god of war.

It is called the ‘Red Planet’ as its surface is covered with red sand and boulders. It has dead volcanoes and deep T-shaped valleys where water once flowed freely.

The planet has white, polar caps of dry ice. It has two sateilites-Phobos and Dimos. No evidence of life has been found on this planet.

The Jupiter :

After the Sun, Jupiter is the most dominant body of the Solar system. It is called “King of the Planets.” Jupiter is the largest planet in the Solar system and is big enough to contain more than a thousand Earths (about 1500).

It is made up of very light matter—a mixture of liquid and gaseous forms of hydrogen and helium. Its mass is equal to the mass of 318 piles of earth. Its equatorial diameter is eleven times that of the Earth.

Like the Earth Jupiter also has its own magnetic field. Along with Saturn, Uranus and Neptune, Jupiter is known .as a ‘Gas giant’, because it is mostly made of gas with no solid surface at all.

The colourful patterns of red, brown, yellow and white on Jupiter’s surface are produced by the chemical sulphur and phosphorus in the swirling atmosphere.

The Great Red Spot’, is its most famous feature. Jupiter has a system of rings consisting of dark grains of dust. It has 63 moons or natural satellites, among them four moons are important. They are Ganymede, Callisto, lo and Europa.

The Saturn :

Saturn is the second largest planet. Saturn is the .most beautiful planet in the Solar system because it is surrounded by a system of many rings. Three well-defined rings have been identified.

These consist of small particles of matter densely packed to appear like a ring of matter revolving around the planet. Besides, these rings Saturn has also 62 satellites.

Of these satellites ‘Titan7 is the largest. Like Jupiter, Saturn is also made up of hydrogen and helium. So, Saturn . is the lightest planet, and if a large ocean were available, Saturn would float on it.

The Uranus :

Uranus is the seventh planet from the Sun and the third largest. It was discovered in 1781 by William Herschel. Uranus is enriched by 11 rings. Uranus is tilted 98° from the vertical. So it is unique among the planets in its axis of rotation lies close to the orbital plane.

Uranus is the most featureless planet to have been closely observed. Its atmosphere contains traces of methane giving the planet a blue-green hue. It has 27 Satellites.

Neptune :

Neptune is one of the furthest planets from the Sun. It is a gas giant and is thought to consist of a small rocky core surrounded by a mixture of liquid and gases. The atmosphere contains several prominent cloud features. Triton is the largest Neptunian moon and the coldest object (- 235°C) in the Solar system.

There are five rings encircling the planet. Like Uranus, Neptune also looks green because of methane in its atmosphere.

Pluto :

Earlier, Pluto was considered as the ninth, smallest, coldest and outermost planet in the

 

Solar System with one named (Charon) and two unnamed satellites. Since 24th August 2006 in the ‘International Astronomical Union’ (IAU) Conference, Pluto was downgraded as ‘Dwarf Planet’.

Dwarf planets are smaller round objects that orbit the Sun. Because their gravitational pull is weak, they have debris within their orbits. They are not however satellites of other planets. Ceres (found in the asteroid belt) and Eris (located in the Kuiper belt) are also dwarf planets.

Journey To Space :

From many thousands of years ago humans wished to gather knowledge about the wandered sky where the twinkling stars, the Sun, the Moon and the other heavenly bodies are all together.

With the progress of time, the study of space is carried out by astronomers with telescopes.

Telescope :

The telescope is an optical instrument using lenses or mirrors or both to make distant objects appear nearer and larger.

Space Suit :

A space suit is a specific dress which is used by someone travelling to space wears a dress filled with and designed to keep out radiation in space.

Rocket:

A rocket is a vehicle used for travelling in space because it is able to overcome gravity and shoot up to space.

 

Spacecraft :

Spacecraft is a vehicle used for travelling in space.

Space Shuttle :

Space Shuttle is a rocket for repeated use, especially between the Earth and a space station. A rocket can take us to space but cannot ensure our safe return to earth. For this, we need a space shuttle.

Space Station :

The space station is an artificial satellite used as a base for operations in Space.

Artificlaf satellites :

Artificial satellites are man-made assemblages of machines and automated devices that revolve around the earth. Many countries have launched their satellites.

They help in the weather forecast, aviation, navigation, communication and other branches of space research. For example, in 2012 NASA of the United States of America sent the rover ‘Curiosity’ to Mars.

Its main objective was to facilitate research regarding the availability or presence of water, soil, weather and life on Mars. The first artificial satellite to the space is Sputnik-1 (meaning Baby Moon in the Russian Language). It was sent by Russian scientists on October 4, 1957.

The first living being to space:

Lika, the Russian dog was the first living being to venture out to space.

The first Man in space :

Yuri Gagarin was the first man to travel to space. On the 12th of April 1961, spacecraft namely Vostok-I of the Soviet Union with him made its first journey to space. He orbited around the earth and his spacecraft returned safely on the earth after making a complete circle.

The first woman in the space :

The first woman in space was Russian Lt. CoL. Valentina Tereskova. She was sent to the space in Vostok VI on June 16, 1963.

India’s Space Research :

It should be noted that India has made a glorious stride over the space research and space journey. India holds the third position in the world in space research activities.

The first space satellite named ‘Aryabhatta’ was launched on 19th April 1975. It was followed by Bhaskar, Rohini-1, Rohini-2, Apple, INSAT, and so on.

Then after a couple of intense movements India’s ‘Lunar Impact’ Probe,’ launched by tricolour. ‘Chandrayan’-l reached on the moon’s surface on 14th November 2008, at 8: 31 pm.

The major activities of ISRO (Indian Space Research Organization) are at present connected on the regular study of the unnamed satellite sent to space namely INSAT, GSAT, SARAL etc. as Geo-Stationary Satellites and Earth Observation Satellites for weather forecasting and other necessary data collection.

Recently India has sent one spacecraft as Mars Orbit Mission.

Chandrayan-2 :

July 22, 2019, is a historic day for space science and technology in India. India’s space agency or Indian Space Research Organisation (ISRO) on that day (2:43 pm) launched the Chandrayan-2 spacecraft into an orbit around Earth and a 48-day journey towards the lunar south pole, intending to make India the fourth country to reach the Moon.

Chandrayan-2 is intended to be the first aircraft to land near the Moon’s south pole, a region of special interest to lunar scientists. The spacecraft is expected to reach the Moon’s neighbourhood on August 20, 2019.

Notable Indian Astronauts :

Rakesh Sharma :

Rakesh Sharma, the first Indian astronaut visited the space in 1984 along with the Russian astronauts. They spent eight days in space in the Soyuz T-ll space station.

Kalpana Chawla :

Kalpana Chawla was the first Indian woman in space. She went into space as a mission specialist on the space shuttle Columbia in 1997 and spent about 372 hours in space. Her second space mission was on January 16, 2003.

On February 1, 2003, her space shuttle Columbia met with a disaster during re-entry into the atmosphere of the Earth -and Kalpana Chawla, along with all the seven crew members died.

Sunita Williams :

Sunita Williams is an American astronaut of Indian origin. She holds the record for the longest single space flight by women for about 195 days. She is also accredited with a record 50 hours 40 minutes of most space walk time for a woman.

The Moon :

The Moon is the only natural satellite of the Earth. It is the nearest heavenly body being only 3,84,000 km from the Earth. It is about 50 times. Smaller than the Earth and is the Only heavenly body that astronauts have set foot on.

The Moon is very tiny compared to the sun, but it looks as big as the Sun is 400 times farther from the Earth and the Moon. The Moon is the brightest object in the night sky. The Moon travels round the Earth once in about 27. days 7 hours and 14 seconds. This is called ‘Lunar Month’.

The Moon takes roughly the same time to spin around its axis once. Thus the same sHe (near side) of the Moon always faces the Earth. There is no life, no air, no sound and no water on the moon.

The surface of the moon has many dead volcanoes with large craters, numerous hollows created by meteorites and vast dust-covered rocky plains known as ‘Maria’ or seas.

Since the low-lying parts and the hollows remain in shadow, they look like dark patches. The Moon has no atmosphere because its gravity, only one-sixth that of the Earth, is not strong enough to hold down gases.

However, its gravity is strong enough to pull the Earth’s oceans and causes tides. The temperature on the Moon reaches extremes from 100°C on its nearside (Sunlit side) to – 180°C on its far side (dark side).

Phases Of The Moon :

We often see just a part of the Moon which becomes larger or smaller light by night. As the Moon revolves around the Earth, its shape appears to change.

This is because different portions of the lighted face of the Moon can be seen from the Earth at different positions. The changes in the Moon’s appearance from ‘New Moon’ to ‘Full Moon’ and again from Full moon to New moon. Every month the Moon goes through all its phases.

Lunar Eclipse :

An eclipse occurs when the Sun, the Earth and the Moon become collinear i.e., they are in a straight line in the plane of the ecliptic. On certain full Moon, days if the bright Moon gradually becomes darkened either partially or totally, it appears as though some dark shadow falls on its face.

The dark zone of the Earth’s shadow is called Umbra. When the Moon happens to pass through that dark zone, it experiences an eclipse. This is called a ‘Lunar Eclipse’.

Expedition To The Moon :

To the early humans as well as scientists the Moon was one of the most fascinating objects. For centuries many facts are known about the Moon.

Space travel and landing on the Moon was a fantastic dream of man for centuries. His dream came true on July 21, 1969, when an American astronaut, Neil Armstrong, placed his foot on the surface of the Moon.

Armstrong and two other Americans, Edwin Aldrin and Michael Collins travelled to the Moon in a spacecraft named Appolo-11. As the craft came near the Moon, it kept on orbiting the Moon while the astronauts prepare to land.

Michael Collins stayed in the spacecraft while the other two entered the lunar module ‘Eagle’. The Craft that was to land on the Moon. When everything was ready, the Eagle separated from the Principal spacecraft and headed towards the Moon to make a soft landing on the Moon’s surface.

At last the Eagle was landed safely and Neil Armstrong came out- from the Eagle and stepped down slowly on the surface of the Moon. Then Aldrin followed him.

Thus Neil Armstrong became the first man to walk on the Moon. From the surface of the. Moon, the astronauts looked at the shining Earth in the black lunar sky and took photographs.

After spending about 24 hours on the Moon, they entered into the Eagle and set off to meet the orbiting space-craft Apolfo- 11 which finally brought them back to the Earth on July 24, 1969.

The conquest of the Moon is, indeed, a great achievement and 21st July 1964 is a red letter day in the history of human civilization.

WBBSE Notes for Class 6 Junior School Geography

 

 

Chapter 3 Location Of A Place On The Earth’s Surface: Where You Are? Introduction :

Location Of A Place On The Earth’s Surface:

A majority of human beings have their homes located in villages or towns on our Earth. Our Earth being a sphere, a poses a problem of where to begin for the location of points.

A globe is a model of the Earth. The parallels of latitude and meridians of longitude make a system of intersecting lines, the former east-west and the latter north-south, found on the globe or in the maps.

Such a system- has many advantages and makes it easier to locate any place on the Earth or on the map.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

The Globe :

A globe is the representation of the Earth while a map is a two-dimensional representation of the Earth or Globe according to a scale and it is drawn on a flat surface.

The globe is a true model of the Earth and shows us what the Earth actually looks like. If we take a close look at the globe we can detect the following features and lines which help us to locate the position of a place on the Earth.

Axis Of The Earth :

The imaginary line joining the northern and southern ends of the globe and passing through the centre of it is called Earth’s axis or ‘Axis of the Earth’. The Earth rotates on this axis.

The Poles :

The endpoints on the Earth (globe) at the top and the bottom are called the ‘Poles’ of the Earth.

North Pole :

The northern or top end point of the Earth’s axis is called the ‘North Pole’.

South Pole :

The southern or bottom endpoint of the Earth’s axis is known as the ‘South Pole’.

Parallels Of Latitudes :

On either side of the equator east-west extending imaginary circles, lying parallel to each other are called parallels of Latitude or Lines of Latitude.

Characteristics Of Parallels Of Latitude :

Parallels of latitudes are imaginary full circles on the Earth, all parallel to the equator i.e. they always remain equal and different apart.

1. All parallels represent true east-west lines.
2. Parallel of latitude intersects meridians at right angles.
3. All parallels except the equator are smaller circles.
4. The Equator is a ‘Great Circle’ and the only parallel drawn from the Earth’s centre.
5. At Every point on the globe, except the North Pole and the South Pole, an infinite number of parallels may be drawn.
6. More than one parallel of latitude of the same value does not exist in one hemisphere.
7. The value of the parallel of latitude is measured from the equator (0°) northwards to the point of the North Pole (90°N) and southwards to the South Pole (90°S).

Equatorial Plane :

The plane bounded by the equator of the Earth is known as the ‘Equatorial Plane’.

If the Earth could be sliced into two halves all along the Equator, the Equatorial plane could be seen and the Earth could be divided into two equal halves. The axis of the Earth forms an angle of 90° with this plane.

Orbit Of The Earth :

While the Earth is revolving around the Sun on a fixed imaginary elliptical (oval-shaped) path, it is called the ‘Orbit of the Earth’.

Orbital PIane :

The Plane containing the orbit of the Earth is known as the ‘Orbital Plane’. The axis of the earth is tilted at an angle of 661/2°to to the orbital plane and 23%° to the vertical.

Importance Of Parallels Of Latitudes :

1. Parallels of latitudes help in location of a place for show how far a place is north and south of the Equator.
2. These are used to divide the Earth into temperature belts. Thus the latitude of a place gives an idea about climate.

Important Parallels Of Latitudes :

Important parallels of latitude and their distance from the Equator in degrees are given below :

The Equator/Great Circle   = 0°
Tropic of Cancer                = 231/2°N or’ 23°30’N,
Tropic of Capricorn           = 231/2°S or 23°30’S,
Arctic Circle                      = 661/2°N or 66°30’N,
Antarctic Circle                = 66°1/2S or 66°30’S.

The Equator/Great Circle :

1. North Pole = 90°N,
2. South Pole = 90°S.

The equator is an image on the globe passing through the midpoints between the North Pole and the South Pole. It is a circle whose centre is the centre of the globe. The Equator divides the globe into two hemispheres.

The hemisphere that lies north of the Equator or that contains the Norm Pole is known as the Northern Hemisphere and the Hemisphere south of the Equator or that contains the South Pole is the Southern Hemisphere.

The word ‘hemisphere’ means half of a sphere or globe. The Equator is also called the ‘Great Circle’ because it is the greatest parallel and other parallels decrease in size gradually.

Another name of the Equator is the ‘Line of Equinox’ because throughout the year the equatorial region has equal lengths of day and night.

Properties Of The Euator/Great Circle :

1. The Equator or Great circle divides a giobe into two hemispheres.
2. It is the largest circle on a sphere.
3. A plane passing through the centre of a sphere only can produce a great circle.
4. The value of the great circle is 0°.
5. An arc of a great circle is the shortest surface distance between any two points on a sphere.

Meridians Of Longitude :

Lines of Longitude or Meridian of Longitudes are imaginary lines joining places located at the same angular distance east or west of the Prime Meridian.

Characteristics of Meridians of Longitude :

1. Meridians of longitudes are half circles.
2. These are measured from the Prime Meridian.
3. These lines extend in a north-south direction on the Earth.
4. All lines of longitudes are of equal in length but not parallel to each other.
5. The distance between two lines of longitude is maximum at the equator and decreases gradually away from the equator.
6. The longitude of a meridian has a definite value.
7. Value of the meridians of longitude increases from the Prime Meridian to the east and west up to 180°.
8. 180°E and 180°W meridian of longitude is one line.
9. The lines of longitudes are converge at the two poles.
10. All places on the same meridian have sunrise, noon and sunset at the same time.

Important Meridians :

Prime Meridian :

North-South extended semicircular the particular imaginary line drawn along the Royal Observatory of Greenwich near London is called the ‘Prime Meridian’ whose value is 0°. This is also known as the ‘Greenwich Meridian’.

Eastern Hemisphere, Western Hemisphere :

The Prime Meridian divides the Earth into two equal halves or the eastern and western hemispheres. The eastern half (from the Prime Meridian to ISO E) is known as Eastern Hemisphere and the Western Half 0°. (from the Prime Meridian#* to ISO’W) is the Western Hemisphere.

180° Meridian of longitude :

The 180° meridian of longitude is just on the opposite meridian of longitude of 0° (Prime Meridian). The International Date Line (IDL) is drawn almost along this meridian from which each new date starts and each date ends at last.

Difference between Parallels of Latitudes and Meridians of Longitude :

 

Parallels of Latitudes	Meridians of Longitude
1.    The Imaginary horizontal circular lines drawn by joining places have the same longitude arc called Parallels of Latitudes.	1. The Imaginary vertical semicircular lines drawn by Joining places having the same longitude are called Meridians of longitude.
2.    These lines encircle the Earth in east-west lines	2.    These lines extend In a north-south direction on the Earth.
3.    These are measured from the Equator.	3.    These are measured from the Prime Meridian.
4.    These are nearly equidistant from each other.	4.    These are not at equidistance everywhere.
5.    Every parallel of latitude are full circle except the two poles.	5.    Meridians of longitudes arc half circles.
6.    The length of the parallels of longitudes gradually lessens from the equator to the Poles.	6.    All meridians of longitudes have the same length.
7.    In the same parallel at different places sunrise, noon and sunset occur at different times.	7.    All places on a particular meridian sunrise, noon and sunset occur at the same time.
8.    The highest value of the parallels of latitude is 90°	8.    The highest value of meridians of longitude is 180°.
9.    The lowest value is 0°.	9.    The lowest value Is 0°.
10. Parallels of latitude help in dividing the Earth’s surface into heat belts or temperature zones.	10. Meridians of longitude help In determining the time zones.

 

WBBSE Notes for Class 6 Junior School Geography

Physical Divisions Of India And Their Influence On Human Life

The land of India is characterised by great diversity in its physical features. It is diversified in respect of relief, drainage, climate, soil, natural vegetation etc.

Physiography Of India :

Among the physical aspects of the geography of India, physiography or relief refers to the physical features of lofty mountains, vast plateaus, extensive plains, deserts and coastal regions etc.

Physiographic Regions of India :

Physiographically, India can be divided into the following physiographic macro divisions.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

(1) The Northern Mountainous Region,
(2) North Indian Riverine plains or the Indus-Ganga plain and Brahmaputra valley.
(3) The Peninsular Plateau Region,
(4) The Desert Region of the West,
(5) The Coastal Plains, and
(6) Indian Islands.

The Northern Mountainous Region :

Location and Extent :

The northern mountain region is located to the extreme north of India. It is like a wall extending from Jammu and Kashmir to Arunachal Pradesh. From west to east, its distance is about 2500 km and its width or north to south distance is about 250 km to 400 km.

Major Mountains :

The Northern mountain region comprises :

• The Himalayan mountain range.
• The Karakoram range.
• The Ladakh range .
• The North-Eastern Mountain region or Purvachal.

The Himalayas :

The Himalayan mountain range is the most important mountain range here. It means ‘home of ice’ or ‘abode of snow’. The Himalayas extends from ‘Nanga Parvat’ (8126 m.) in Jammu and Kashmir in the west to ‘Namcha Barwa’ (7755 m.) in Arunachal Pradesh in the east for a distance of about 2500 km and a width of about 250 km to 400 km. The shape of the Himalayas is like an arc.

South To North Regional Divisions Of The Himalayas :

The Himalayas consist of four parallel ranges from south to north :

1. The Siwaliks
2. The Lesser Himalayas or Middle (Inner) Himalayas
3. The Hlmadri or the Greater Himalayas and
4. Trans- Himalayas.

The Siwalik :

The southernmost range of the Himalayas is known as the Siwaliks or the ‘Outer Himalayas’. The average height of the Siwaliks is about 1000 metres-with a width ranging from 15 to 50 km.

The Siwaliks consist of the foothills which run -through as the foothills of the Himalayas. They are composed of highly unconsolidated deposits of the Himalayas. They were called ‘Upagiri’ by the ancients. These ranges are discontinuous and are not found in the Eastern Himalayas.

Doons:

Narrow longitudinal valleys lying in between the Siwaliks or outer Himalayas and the lesser or Inner Himalayas are known as ‘Doons’ or ‘Duns’. These are formed by the deposition of sediments.

The Duns in the Kumaon Himalayas such as Dehradun, Kothri dam, Patali, Kulu, and Kangra in Uttarakhand and Himachal Pradesh are well known. These beautiful valleys contain fertile soil and they are agriculturally developed and prosperous.

Terai :

The Terai is a marshy/swampy strip of land (with grasslands and forests) located in between the outer foothills of the Himalayas-the Siwaliks and the northern plain of the Ganga, Brahmaputra and their tributaries.

In northern India, the Terai spreads eastwards from the Yamuna river across Uttarakhand, Haryana, Uttar Pradesh and Bihar and southern part of Nepal. Corresponding parts of West Bengal, Bangladesh, Bhutan and part of Assam, east to the Brahmaputra river are called ‘Doors’.

The Naga and Patkoi hills at the eastern border of India and Garo, Khasi and Jayantia hiJIs in Meghalaya belong to the Terai region. The lowlands plains of the Terai lie at an altitude ranging between 67 and 300 metres.

The Middle or Inner Himalayas :

The middle (inner) or lesser Himalayas lies in the north of the Siwaliks and south of the great Himalayas and stretch parallel to them. The average height of this range ranges from 3500 to 4500 metres.

Dhauladhar, Pir-Panjal, Nag Tibba and Mussourie ranges are some of the important ranges here. Among the ancients, they were known as ‘Antagiri’ or ‘Himachal’.

The picturesque hill stations of this region-Shimla, Manali, Nainital, Mussoorie, and Darjeeling are located here and attract tourists from all over the world.

Himadrl or the Great Himalayas :

This range is extending from Nanga Parvat in the west to Namcha Barwa in the east. The Himadri Himalayas comprise all major mountain ranges of the Himalayas. It is the highest part of the Himalayas.

Great Himalayas is the loftiest range because it contains most of the ‘eight thousand peaks’ of the world. The average elevation of the Himadri is about 6000 metres and it is permanently covered with snow.

Mt. Everest (8848 m), the highest peak of the world is located here. There are some other peaks, such as Kanchenjungha (8598 m), Dhauligiri (8172 m), Nanga Parvat (8126 m), Annapurna (8076 m), Nandadevi (7817 m).

Kanchenjungha is considered as the third-highest mountain peak of the world.

Trans-Himalayas :

The Trans-Himalayas or the Tethys Himalayas consist of ranges like ‘Karakoram’ farthest in the north. The second highest mountain peak of the world Mt. Godwin Austin (8611 m) or ‘King of Karakoram’ (K2) stands here.

It is considered as the highest mountain peak of India. A number of large glaciers are found along the southern face of the Karakoram. It has an average height of 5000 m to 6000 metres. The Himalayas merge with the Tibetan Plateau.

West to East Regional Divisions of the Himalayas :

From the west to the east the Himalayan range can be divided into three sections :

1. The Western Himalayas
2. The Central Himalayas and
3. The Eastern Himalayas.

1. The Western Himalayas include the Himalayas of Jammu and Kashmir, Himachal Pradesh, Punjab and Uttarakhand. It is called the ‘Trans-Himalayas or Tethys Himalayas’. They are made up of the Ladakh Range, Zanskar range and the Pir-Panjal Range.

2. The Central Himalayas lies in Nepal.

3. The Eastern Himalayas extends from the Singalila in the west to the Namcha Barwa in the east.

It can be divided into three sub-divisions—

1. Sikkim- Darjeeling Himalayas,
2. Bhutan Himalayas and
3. Arunachal or Assam Himalayas.

Mountain passes :

There are a few mountain passes in the Northern mountain region. Important passes in India and their location are as follows :

Banihal pass (Jawahar Tunnel) and Zojila located in Jammu and Kashmir; Shipkila and Bara Lachala in Himachal Pradesh; Nathula and Jelepla in Sikkim and Bomdila in Arunachal Pradesh.

Glaciers:

A glacier is a large mass of moving ice or a river of ice. There are many glaciers in the Northern mountain region of India. Important glaciers are as follows

Glaciers in the Karakoram Ranges :

1.  Siachen, the longest glacier in India,
2. Baltaro glacier,
3. Biafo Glacier etc.

Glaciers in the Himalayan Ranges :

1. Gangotri glacier (39 km) Uttarakhand,
2. Yamunotri Glacier (30 km) is located in Uttarakhand,
3. Zemu Glacier (26 km) is located in Sikkim,
4. Milam Glacier (15 km) is located in the northeast of Nandadevi (Uttarakhand).

The Influence Of The Himalayas On The Human Life In India :

 

 

Establishment of Health-restoring centers:

Several hill stations like Kalimpong, Darjeeling, Dalhousie, Shimla, Almorah, etc. have been developed in the Himalayas. There are numerous other benefits like scenic beauty, tourist-attractive sanatorium, freshwater lakes etc.

The North Indian Riverine Plains :

This plain is also known as the Indus-Ganga Plain and Brahmaputra Valley or as the Great Plain of Northern India.

Location :

This plain is located on the south of the Himalayas and north of the Peninsular Plateau of India, It is extending from Punjab to Assam valleys. It is about 3200 km long and 150 to 300 km wide.

Divisions :

North Indian riverine plains can be divided into three divisions.

These are—

(1) The Punjab Plain drained by the Indus and its tributaries,
(2) The Ganga Plain drained by the Ganga and
(3) The Brahmaputra valley is drained by the Brahmaputra.

Characteristics :

1. Although this plain is level and monotonous in nature, some local differences are observed.
2. Its average height is about 150 metres.
3. It covers an area of 7-5 lakh sq. km.
4. It is an alluvium filled through.
5. It has been formed by the deposits of sediments brought by the Himalayan rivers (Ganga, Sutlej etc.)
6. This plain is the most populous part of India because this region is agriculturally and industrially developed.

Major Rivers Of The North Indian River line Plains :

The description of the major rivers, the Ganga, the Brahmaputra and the Indus that form this plain is given below :

The Ganga (2510 km) :

The Ganga (Ganges) is an ideal river as well as the longest (2510 km) and principal river of India.

The Course Of The Ganga :

The river rises from the icy cave of Goumukh of Gangotri glacier on the Kumaon Himalaya from the source to the mouth. The river can be divided into three courses-the upper course or mountain course, the middle course or plain course and the lower course or delete course.

The upper Course :

At the source, the Ganga is known as Bhagirathi. It flows towards the southwest through a narrow gorge and joins the Alkananda near Devaprayag. The combined flow of Bhagirathi and Alakananda is known as ‘Ganga’.

At Rudraprayag Mandakini rising from ‘Gouri Kund’ joins Ganga. The Ganga flows for about 320 km. in the mountainous region and then comes down to Hardwar. So, the course of Ganga from Goumukh to Hardwar is its upper course or mountainous course.

The middle course :

From Hardwar to Rajmahal hill the river Ganga covers its ‘plain’ or ‘middle’ course. In this course the Yamuna, the largest tributary of the Ganga flows parallel to the river Ganga till its confluence with the Ganga of Allahabad.

The lower course :

From the Rajmahal hill area to the Bay of Bengal the river Ganga covers its lower course. After crossing the Rajmahal hill in Bihar, the Ganga enters in West Bengal.

Near Dhulian in Murshidabad, it is divided into two distributaries-the Padma and the Bhagirathi. The Padma flows towards the southeast and enters into Bangladesh, there it joins the Brahmaputra and Meghna and finally drains into the Bay of Bengal.

The Bhagirathi turns southwards and flows as the ‘Bhagirathi’ at first. Then from Nabadwip in Nadia, it flows up to the mouth of the Bay of Bengal as the name of the ‘Hugh’ river. It merges with the Bay of Bengal forming an estuary and a huge delta.

This delta is famous as ‘the Ganges delta’ or ‘the Ganga-Brahmaputra-Meghna delta. The Ganga basin is the largest part of the northern plains of India.

The soil of this vast plain is the most fertile and it is the major crop-growing area of India. This plan is known as the ‘food bowl of India’.

The Ganges at a Glance

1. Length: 2510 km.

2. Special Features: Largest river of India

3. Major Tributaries : Yamuna, Son, Gomti, Gandak, Kosi etc.

4. Distributaries: Padma and Bhagirathi.

5. Major cities along its course: Hardwar, Kanpur, Allahabad, Benaras, Patna, Kolkata etc

2. The Brahmaputra :

Brahmaputra River:

The Brahmaputra is an international river. Since ancient times is it an important river of India Brahmaputra means ‘son of lord Brahma’. The total length of the river is about 2900 km. In India, it is about 885 km. long.

The Course of Brahmaputra :

The Brahmaputra originates in the ‘Chemayundung glacier south-west of ‘Manas Sarovar’ or about 90 km southeast of ‘Rakshas Tal’ in Tibet where it is known as ‘Tsangpo’.

It breaks through the Himalayas in deep gorges near the peak of ‘Namcha Barwa’ in Arunachal Pradesh and bends southward to enter India in the name of ‘Dihang’.

The Dihang, after its union with ‘Dibang’ and ‘Lohit’, gets the name ‘Brahmaputra’ in Assam and flows towards the west (from the east of Sadiya to the west up to Dhubri). The river finally bends southward to meet the ‘Padma’ as the Yamuna river and finally drains into the Bay of Bengal forming a great delta in its mouth.

It is known for its notorious floods and sand deposits. The Brahmaputra flows slowly over the Assam valley due to the gentle slope of the land.

Thus the river flows through pronounced meanders and has many sandbanks and sand bars (Island/char) along its channel. The largest river island in the world lies in this river and is called ‘Majuli’.

Frequent earthquakes in the Assam valley has caused the Brahmaputra to change its course quite often. The Brahmaputra is known as the ‘Red River of India’ because the water of this river looks reddish in colour especially during floods after mixing with the red soil of Assam.

The important right bank tributaries of the Brahmaputra are Subarnashree, Barali, Manas, Sankosh, North Dhansiri (Dhanashree) and Tista. Itanangar, Nowgaon, Tejpur, Guwahati, Digboi and Dibrugarh are few of the major cities on the bank of river Brahmaputra in India.

Brahmaputra valley is drained by the river Brahmaputra and its tributaries. Most of the these rivers are rainfed as well as snow-fed. During the rainy season due to heavy rainfall the rivers overflow their banks and floods occur several times.

The Brahmaputra at a glance

1. Length: 2900 km.

2. Another name: Tsangpo in Tibet., Yamuna in Bangladesh.

3. Tributaries: Dibang, Lohit, Manas, Dhanashree, Subarnashree, Tista, Torsha etc.

4. Major cities along its course: Itanagar, Dibrugarh, Guwahati etc.

(3) The River Indus :

The river Indus is a very important river in north-western India. It has a length of about 2880 km. but only 709 km is in India. According to one view, the Indus rises from the ‘Sengge Khabab’ glacier or spring at an altitude of 5180 metres of the Kailash range in the southwest Tibetan plateau.

Another view states that it rises from the ‘Manas Sarovar’ lake located on the northern slopes of the Kailash range, in Tibet. Both areas are close together.

Indus at a Glance

1. Length: 2880 Km.

2. Tributaries: Bitasta, Chandrabhaga, Bipasha, Iravati, Shatadru.

3. Flows through Himachal Pradesh and Jammu and Kashmir.

4. Major cities along its course: Led, Srinagar

The course of Indus :

From the source it flows northwest through Tibet and Jammu-Kashmir between the Karakoram and Ladakh ranges covering a distance of about 250 km. Near Nanga Parvat peak it turns around the mountain in deep gorges, to flow southwest wards into Pakistan, and ultimately it drains into the Arabian Sea.

It is Pakistan’s longest river. Among the right bank tributaries of the Indus as its upper course, the Shyok and Shigar are notable. The Zanskar, Dras, and Astor are its left bank tributaries.

The mighty five tributaries of the Indus are the Sutlej (Shatadru), the Beas (Bipasha), the Ravi (Irabati), the Chenab (Chandrabhaga) and the Jhelum (Bitasta). They are collectively known as ‘Panchanad’. The name of Punjab is derived from these five rivers of the Plain.

The Rivers of the Deccan Plateau :

Name of Rivers	Source	Direction of Flow	The mouth of the River
Mahanadl	Sihawa range in Dandakaranya highland.	East	Bay of Bengal
Godavari	Trimbak Highland (hills) of Sahyadrl near Nasik.	East	Bay of Bengal
Krishna’	Mahabaleswar in Western Ghats.	East	Bay of Bengal
Kaveri	Brahmagirl In Karnataka	East	Bay of Bengal
Narmada	Amarkantak peak of the Mahakala range of Madhya Pradesh	West	Gulf of Khambat
Tapi (Tapti)	The Mahadev Mountain range.	West	Gulf of Khambat

 

The Peninsular Plateau Region :

The Great Peninsular Plateau of India is the oldest structure of India. Geologically, it is a part of the ancient landmass of the world, the ‘Gondwanaland’. The Peninsular plateau lies to the south of the Northern Plains of India.

It is a region more or less triangular in shape. It is bounded by the Aravalli range in the northwest and Rajmahal in the northeast. In the northeast, the plateau extends into the Meghalaya Plateau. This plateau is a tilted plateau in nature.

The plateau slopes from west to east. The region is mainly composed of ancient granite and gneiss rock. The north-western portion of the plateau is composed of ancient granite (basalt rock).

The prolonged denudation has changed the plateau into dissected plateaus and peneplains at some places. Different residual ranges like Mahakal, Western ghats, Eastern ghats etc. are found here.

Based on variation in landform, this plateau may be divided into three regions-

1. The Central Highland
2. The Eastern Highland and
3. The Deccan Plateau.

The Central and Eastern Highlands of India :

The Central Highland:

The Central Highlands covers the highlands of Rajasthan, Madhya Pradesh, and Uttar Pradesh. It extends from Aravalli in the west and Rajmahal in the east. The southern boundary is limited by the Vindhyas, Satpuras, Mahadev, and Mahakal Raimur range.

The Aravallis :

On the Western border of Central Highland stands the Aravalli, the oldest fold mountain of India as well as the world. Guru Shikhar (1722 km) is the highest peak of Aravalli.

The ‘Vindhyas’ is the most important range of this highland has an average elevation of 300 meters and is the source of the river ‘Chambal’. To the west of the Vindhyas is located the ‘Malwa Plateau’.

The northeastern part of the Malwa Plateau is composed of pink granite and is known as the ‘Bundelkhand Plateau’. The eastern part of the Vindhya range is known as the ‘Rewa Plateau’. The Narmada valley in the south, the Chambal valley, and the Son valley in the north form a typical landscape.

The Eastern Highlands :

The Eastern Highlands comprises Chhotonagpur, Chhattisgarh, and Mahanadi Basin. and the plateau of Chhattisgarh and Dandakaranya of Odisha. This highland is dominated by the Chhotonagpur plateau.

‘Pat’ region, the Pareshnath hill (1366 m.) is the highest point in this region. The famous ‘Ranchi Plateau dissected by the river Damodar lies the Hazaribagh Plateau where stands the ‘Pareshnath Hill’.

The Rajmahal hills form the north-eastern boundary of this region. South of the Ranchi Plateau lies the Garhjat hill region.

The Deccan Plateau :

The Deccan Plateau is the largest plateau of India. It extends from the Vindhya range in the north to the Kanyakumari (Cape Camorin) in the south.

It is surrounded by mountain ranges on three sides-VVestern Ghats or Sahyadri on the west, Eastern Ghats or Malayadri on the east, and Satpuras and Vindhyas on the north. Deccan Plateau is a tilted plateau with a general eastward slope.

It covers an area of 70 lakh sq. km. Its average height varies between 500 m to 1000 meters. The plateau is a part of the ancient Gondwanaland of the world. It is composed of ancient igneous rocks like granite, basalt, etc. And metamorphic rocks like gneiss. The Deccan Plateau comprises the following physiographic divisions.

Western Ghats :

Western Ghats extend from Tapi (Tapti) valley up to Kanyakumari for about 1500 km. It has three passes-Thal Ghat, Bhorghat, and Palghat. These range abruptly from the coast.

Short swift streams flow towards the west and do not form deltas. The average height is about 1200 meters. Godavari, Krishna, and Kaveri rivers rise from the Western Ghats and flow towards the east.

Maharashtra Plateau :

The north-western part of the Deccan Plateau is known as Maharashtra Plateau. It is formed of lava (basalt) rocks lying in a series of steps. Hence, it is called Lava Plateau. It is also known as the ‘Deccan Trap’ (Swedish ‘trap’ means ‘steps’). Erosion of the basalt rock over a long period of time has produced rich black soil (Regur).

Karnataka Plateau :

Further south of Deccan Trap is the Karnataka Plateau. The 600 meters contour line may be taken as the boundary of the Karnataka Plateau. The plateau meets the Western Ghats in the west and Eastern Ghats in the east.

Physiographically the plateau can be divided into two parts—

(1) Hilly ‘Malnad’ region in the west and
(2) Flat ‘Maidan’ region in the east.

Telangana Plateau :

The Telangana plateau is a rolling surfaced plateau with intervening shallow depression. It is in former Andhra Pradesh (Now it is included in the newest Indian state ‘Telengana’.)

The Desert region in the west :

The south-Western part of the plains of Northern India is known as the Rajasthan plain. It lies in the west of the Aravalli range. It enters into Pakistan. The plan is extensively sandy plain. This arid and barren plain is regarded as a desert.

Different types of sand dunes are found in the western portion of this plain. This desert region is known as the ‘Thar Desert’. The Thar Desert is also known as the ‘Great Indian Desert.

Characteristic Features of the Great Indian Desert :

The western portion of Rajasthan which is generally regarded as the “Great Indian Desert” or Thar. The important features of this region are as follows :

1. Thar desert is a part of the Rajasthan Plain.

2. To the east it rises to 325 m and the west it falls to 150 m.

3. Barkhans, seif dunes, etc. are found in this region.

4. The main characteristic features of this region are extremes of climate and extensive sandy plains.

5. Mobile sand dunes of this region are known as “Dhrians”.

6. Dry lakes or almost dry lakes are also found in this region. These saline lakes are called locally as “Dhands” viz. Panch Padra, Didwana etc.

7. The region slopes to the west into the Indus valley and to the south in the Rann of Kachchh.

8. The average annual rainfall is only 25 cm. So, the rainfall is very low here.

9. Very little vegetation are grown here. Patches of thorny bush and grass are found in certain areas.

10. In summer the temperature rises up to 50°C and in winter it drops to 5°C.

11. Short inland drainage basins and water lakes are seen here. Luni is an important inland river and Lake “Sambar” is a typical example of salt water lake on the desert.

12. Population here is very sparse due to the lack of cultivable land, transport, and communication in this area.

Causes of origin of Indian desert in the Thar desert :

1. There is very little summer rain, less than 25 cm annually.
2. Humidity is very low in summer. Before it even in rains the moisture has evaporated. Besides, Thar lacks water sources.
3. Thar, situated in Western Rajasthan, is a comparatively low-lying region with the Aravallis lying parallel to it.
4. The parallel situation of the Aravalli range with the direction of the southwestern Monsoon does not help precipitation. So rainfall received by this region is very scanty.
5. The vast region of Western Rajasthan is mainly covered by sand deposited by the wind.
6. The Tropic of Cancer is passing through this region. So the temperature is very high and because of the high temperature, the raindrops are turned into water vapor when it falls on the sandy surface.

The Coastal Plains :

The Deccan plateau Is fringed with coastal plains. These plains are washed by the Arabian sea on the west and the Bay of Bengal on the east. The coastal plain have two physiographic divisions. The Western Coastal Plains on the west and the Eastern Coastal Plains on the east.

1. The Western Coastal Plains :

The Western Coastal plains lying between the Western Ghat, and the Arabian sea are stretching from Kachchh in the north to
Kanyakumari to the south.

2. The Eastern Coastal Plains :

The Eastern Coastal Plains extends from the mouth of Subarnarekha river (Odisha) in the north to Kanyakumari in the south.

Sub-divisions of the Western Coastal Plains :

The sub-divisions of this narrow coastal plain are—

1. The coastal plain of Gujarat (Northern Part). The coastal plain of Gujarat is wide consisting of Kachchh and Kathiawar Peninsulas. The Kachchh region forms marshes and are called ‘Rann’.

The northern section is known as the ‘Great Rann of Kachchh (Kutch)’ and the south-eastern section is the ‘Little Rann of Kachchh (Kutch)’. This large salt marsh is a barren rocky region.

It gets flooded during the rainy season when the sea level rises. It is considered a part of the Thar desert.

2. The Konkan Coastal Plain :

The Konkan Coastal Plain from Daman in the north to Goa in the south is narrow and broken rocky coast.

3. The Karnataka Coastal Plain :

It is stretching from Goa in the north to Mangalore in the south is wider with sand dunes and marshy lands.

4. The Malabar Coastal Plain :

The Malabar Coastal Plain of Kerala is the extreme southern part of the western coastal plain. It is 95 km wide. There are many sand dunes (locally called ‘Theris’) and ‘Kayals’ (backwaters) like ‘Vembanad’ near Kochi (80 km long) and ‘Austamudi’ near Quilon (Kollam).

The Eastern Coastal Plains :

the mouth of the river Subarnarekha in the north to Kanyakumari in the south for nearly 1500 km.

It may be sub-divided into two divisions,

1. Northern Circars coast and
2. Coromandel coast

Northern Circars coast :

Northern Circars coast to the north of the river Krishna including Odisha coastal plains in between the Subarnarekba in the north and the river ‘Rushikulya’ in the south and Andhra Coastal Plain from mouth of Rushikulya to the lake Pulicat.

Coromandel coast :

Coromandel coast stretches from the south Krishna delta to Kanyakumari. This coastal plain is also known as the ‘Tamil Nadu Coastal Plain’. There are many sand dunes and lagoons in the Eastern Coastal Plain.

The sand dunes along the coast of Tirunelveli and Mahabalipuram rise from 30 m to 65 m high. A few lagoons, namely ‘Chilka’ in the Odisha coast, ‘Kolleru’ and ‘Pulicat’ in the Andhra Pradesh coast are found.

Indian islands :

Indian islands on the Bay of Bengal and the Arabian Sea present an interesting aspect of Indian physiography.

They are divided into two sub-divisions—

•  Andaman and Nicobar islands on the Bay of Bengal and Lakshadweep on the Arabian sea.

Islands of Bay of Bengal Inculding Andaman and Nicobar islands :

These are actually the elevated tops of the submerged mountain ranges. These islands of the Andaman group extend between 10°N and 14°N latitudes for a distance of 500 km. These islands are 214 in number.

The Nicobar group consists of 15 islands extending between 6°N to 10°N latitudes. ‘Ten degrees Channel’ separates to the Andaman group islands from the Nicobar group. These islands form a ‘Union Territory’ of India with Port Blair as its capital.

‘Indira Point’ in Nicobar island is the southernmost point of the Indian Union. These islands form the summit of the submerged hills of the sea/ ocean floor. Barren islands and Narcondum islands situated in the north of Port Blair are volcanic islands.

Lakshadweep Islands :

These islands are situated in the Arabian sea and lie 320 km off the coast of Kerala between- 8° N and 12° N latitudes. These are coral islands and some of these are ring-shaped and called ‘atolls’. These are 27 in number and 17 of these are uninhabited. It is a union territory with Kavarattl as the capital.

WBBSE Notes for Class 6 Junior School Geography

Chapter 10 India – Agriculture Of India Introduction :

Agriculture Of India:

India is an agricultural country. In India, agriculture plays an important role in dominating the economic, social, and cultural life of the people. Agriculture is the principal occupation of the people of India.

More than 70% of the working population maintains their livelihood by cultivation. Agriculture also provides about 50% of India’s national income. The agricultural sector in India contributes about 16% of G.D.P. (Gross Domestic Products) and 10% of export earnings.

India’s agriculture mainly depends on monsoonal rainfall. This rainfall is uneven and irregular. So, in India agriculture is influenced by the availability of proper irrigational facilities.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

Essential elements for agriculture :

There are certain essential elements for effective agriculture, which are as follows :

1. Relief or slope of the land.
2.  Proper Drainage system.
3. Fertile Soil.
4. Proper and timely Irrigation.
5. Fertilizer.
6. High-yielding seeds.
7. Pesticides.
8. Insecticides.
9. Cheap Labour.
10. Storehouse.
11. Capital.
12. Transport.
13. Technology.
14.  Market.
15. Trade and Commerce.

Green Revolution :

The profuse increase in agricultural produce by the use of modern agricultural methods and infrastructure was known as the ‘Green Revolution. In the backdrop of the food crisis that gripped India in the 1960s and 1970s, the government of India initiated the ‘Green Revolution program.

This was an attempt to become self-sufficient in the production of food grain. Instead of the traditional method, farming with chemical fertilizer, high-yielding seeds, pesticides, irrigation, and advanced technologies was introduced.

Impact of Green Revolution :

1.  It helps to an expansion of agricultural land.
2.  Due to this our country became self-sufficient in foodgrain production.
3.  Import of foodgrains has been reduced.
4. Mechanisation of agriculture has increased.
5.  Many agro-based industries have been set up.
6. It also increases the standard of living of the people.

Types of Agricultural, crops :

India is a vast country with a variety of relief, climate, and soil conditions. Therefore a large variety of crops are grown all over the country.

The great variety of crops that are grown in India may be broadly divided into the following types of crops on the basis of their uses

1. Food crops
2. Fibrous crops
3. Vegetable crops
4. Beverage crops
5. Other crops.

These are

Kharif Crops :

Crops cultivated in the beginning of the rainy season and harvested in the end of autumn (September-October) are known as ‘Kharif Crops’. Important kharif crops are-‘Aman’ paddy, cotton, jute, sugarcane, millets, corn, and groundnut.

Rabi Crops :

Crops cultivated in the beginning of the winter or late autumn and harvested in the spring or beginning of the summer are known as ‘Rabi Crops’. Some important rabi crops are wheat, barley, potato, pulses, linseed, and mustard.

Distinguish Between ‘Kharif Crops’ And ‘Rabi Crops’ :

Kharif crops	Rabl crops
1.    Crops sown soon after the onset of the South-West monsoon and harvested in Autumn.	1.    Crops sown in India in winter and harvested in spring.
2.    These are grown after the rains in June-July.	2.    These crops are grown in October-December.
3.    Kharif season has monsoon or summer crops.	3.    Rabi season has winter crops.
4.    Rice (paddy), maize, millets, cotton, jute, and sugarcane are Kharif crops.	4.    Wheat, barley, oilseeds, pulses, potato, etc.

 

Cash Crops :

The crops which are grown, harvested, and sold to earn money, particularly the foreign exchange are known as ‘Cash Crops’. These crops are grown for each rather than for sustenance.

These are used as industrial and trading purposes. Jute, Cotton, etc. are the main cash crops in India. Sugarcane, oilseeds, rubber, etc. are also important cash crops in India.

Special Methods Of Cultivation :

Jhum Cultivation :

The primitive method of ‘slash and burn’ or jhooming (jhum cultivation) is practiced in the states of north-eastern hilly areas by tribal people. By this process, a small place of land is cleared by burning trees and cultivated for 3-4 years after which they shift to another place and cultivate in a similar way.

So, it is a type of ‘shifting cultivation’. As a result, the forest is destroyed and soil erosion takes place rapidly. So, it is indispensable to stop jhoom cultivation to prevent soil erosion.

Terrace Cultivation :

The method of cultivation in hilly areas by making steps on slopes to prevent soil erosion is called ‘Terrace cultivation.

WBBSE Notes for Class 6 Junior School Geography

Chapter 10 India – Soils Of India Introduction :

Soil:

Soil is an important natural resource. Mankind has lived and continues to live on the soil. Many human and economic activities depend upon soils. All our food comes directly or indirectly from the soil.

Livestock farming depends upon the raising of grass on different soils. Soils form an important element for all living things. Soils have affected the march of civilizations.

Soil :

Soil is the topmost layer on the surface of the Earth. The loose inorganic and organic unconsolidated material which forms the uppermost layer of the Earth’s crust and promotes the growth of vegetation cover is called ‘soil’. The soil is consisting of

• Inorganic material derived from rocks;
• Organic matter derived mainly from plant residues;
• Water and air within pores; and
• Millions of small living organisms.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

The Formation of Soil :

The change from hard and rugged rocks to soft, fine-grained soil takes a long time. The first step in this direction is the disintegration or weathering of rocks. The disintegration of rock by weathering often produces a layer of loose rock materials.

This covering of loose materials over the primary rock bed is known as ‘regolith’. Soil is derived from regolith in different natural processes.

The main factors in the formation of soils are-

• Parent rock materials,
• Topography or relief,
• Climate,
• Organic matter (plants and animals) and
• Time.

The texture and structure of soils depend on parent rocks. The climate is considered to be the most important factor in the development of soil. Steep slopes have thin soil layers, whereas the valleys and lowlands possess thick fertile soil.

The soil gets humus from plants. Earthworms and other animals like dogs, squirrels etc. also upturns the soil of the lower layer soils in wet areas require less time to develop than in dry areas.

Soils in different parts of India :

In India, there are different types of soils. The Indian Council of Agricultural Research (ICAR) set up on ‘All India Soil Survey Committee in 1953 which divided Indian soils into 27 types of soils in which 8 types are important. As per the syllabus six of the eight major soil types are discussed below :

Alluvial soil :

Alluvial soil is the principal soil of India. It covers about 46% of the total land of our country.

Location Of Alluvial soil :

The alluvial soils are found in the Vast riverine tract of the Indus, Sutlej, Ganga and Brahmaputra in the Northern Plains, in the deltas of Godavari, Krishna and Kaveri rivers. The states of Punjab, Haryana, Uttar Pradesh, Bihar, West Bengal, Assam, Odisha and other coastal (eastern) states have alluvial soil.

Characteristics Of Alluvial soil :

1. Alluvial soils are deposited by rivers.
2. These soils are limited to river basins and plains.
3. These are very fertile soils.
4. These consist of fine-grained clay and sand.
5. These soils are rich in potash, but poor in phosphorus.
6. These are generally deep soils.

Influence on Agriculture :

Riverine alluvium is very fertile. These soils favour the cultivation of rice, wheat, jute, cotton, oilseeds, sugarcane, millets, pulses, tobacco and vegetable. Coastal alluvial soil is developed in paddy, coconut, and green chilly cultivation. So, the alluvial soil is regarded as the best soil of India for its high agricultural value.

Black soil :

This is the second most important soil of India. It is popularly known as ‘Regur’ and ‘black cotton soil’ also. It covers about 17% of the total land area of India.

Location Of Black Soil :

Black soil is found in the ‘Deccan Trap’, especially in Maharashtra, the southern part of Gujarat, Madhya Pradesh, the Northern part of Karnataka, Telangana and Northern part of Tamil Nadu.

Characteristics Of Black soil :

1. This soil is produced from lava rock ‘basalt’. The colour of basalt is black. Hence, colour of this rock is black.
2. It contains calcium, magnesium, carbonates, iron-oxides and humous
3. Nitrogenous materials are totally absent in this soil.
4. It has high water retentive capacity.
5. It is sticky in nature.
6. It is fine-grained and clay soil. As cotton thrives well in this soil, it is popularly known as ‘Black Cotton Soil’.

Influence on Agriculture :

Regur or Black soils are fertile and are suitable for cotton, wheat, sugarcane and groundnut production.

Red soil:

This soil is formed by the breaking down of metamorphic rocks over the year. It is red in colour of the high of iron that it contains.

Location Of Red Soil :

This soil is found in peninsular India, particularly in the states of Odisha, Jharkhand, Chhattisgarh, Telangana, Andhra Pradesh, Tamil Nadu, Kerala, Manipur, Mizoram, Nagaland, Arunachal Pradesh and the Western part of West Bengal.

Characteristics Of Red Soil :

• This soil is a mixture of sand and clay.
• It is red in colour as it contains a great proportion of iron oxides.
• It is deficient in nitrogen, phosphoric acid and humus, but it is rich in potash and lime.

Influence on Agriculture :

This soil is relatively less fertile, but cultivation is possible with the help of irrigation and fertilizers. Ragi, rice, wheat, millets, nuts, pulses, sugarcane, oilseeds, cotton and chick peas are cultivated on these soils.

Laterite soil :

It takes place under typical monsoonal conditions. The alteration of wet and dry seasons leads to the leaching away of the siliceous matter of the rocks and the formation of laterite soils takes place.

Location Of Laterite Soil :

They are commonly found in Karnataka, Kerala, Tamil Nadu, Maharashtra, Madhya Pradesh, Chhattisgarh, Odisha, Chhotonagpur plateau, mountains in Western Ghats and Eastern Ghats, and in large areas of plateaus in Meghalaya.

Characteristics Of Laterite Soil :

• The laterite soils are hard as a brick (‘later’ means brick). So, it is named by laterite.
• Laterite soil is formed in areas of high temperature and heavy rainfall where dry and wet seasons follow each other.
• It is red in colour because of the high amount of iron oxide that contains.
• These are shallow, acidic and less fertile.
• These are less fertile due to the leaching of soil.
• These are poor in nitrogen, and potash, but rich in iron.

Influence on Agriculture :

Though this soil is infertile, it is unsuitable for agriculture. Hardy crops like jowar, bajra, ragi, groundnuts etc. are cultivated on this soil.

Desert soil or soil of desert region :

This soil is formed in areas of little rainfall and excessive temperature.

Location Of Desert Soil :

These soils are found in Rajasthan deserts, the southern part of Punjab and the Rann of Kachchh.

Characteristics Of Desert Soil :

1. These soils contain coarse brown sands.
2. They are granular and very porous.
3. It has the little water-retaining capacity and is infertile.
4. The amount of salt In this soil is high because of excessive evaporation.

Influence on Agriculture :

These soils are not suitable for agriculture. Millet like ragi, bajra and wheat, groundnut can be grown on these soils.

Mountain soil or soil of mountainous region :

This soil is formed in a humid temperate climates.

Location Of Mountain Soil :

It is found particularly in those areas which have mountains or hill ranges, these soils are found in the states of Jammu and Kashmir, Himachal Pradesh, Arunachal Pradesh and Uttarakhand. These are also found in Nilgiri hills and hills in Western Ghats

Characteristics Of Mountain Soil :

1. These soils are made of rock, boulders and clay.
2. It contains a large amount of organic matter.
3. These are generally light black in colour with a large number of rock particles.

Influence on Agriculture :

These soils cannot be termed good from the point of view of agriculture. However, these soils are suitable for cultivating tea, coffee, rice, fruits and different spices.

The Uses of Soils :

Soil is a fundamental natural resource. There are various uses of soils. The important uses of soils are as follows :

1. Agriculture is not possible without soil as it is the storehouse of plant nutrients.
2. Soil is a natural habitat for various insects, earthworms and microscopic creatures.
3. Livestock farming depends upon the raising of grass on different soils.
4. Soils help to maintain humidity in the environment.
5. The soil is used as materials for the construction of buildings etc.
6. The soil is used for clay modelling.
7. Soils are the origins of plants and forests.
8. Soils help to establish cottage industries.

Soil Erosion :

Soil erosion may be defined as the detachment and transportation of soil by agents of denudation such as weathering; running water and wind etc. It is the destruction and removal of topsoil.

Soil erosion has become a serious problem in many areas of India as well as the world. Soil erosion results from the following causes :

Causes of Soil Erosion :

 

Soil Conservation :

The process of preventing soil erosion and degradation by natural as well as artificial methods is known as ‘soil conservation’. The different methods of soil conservation are as follows :

(1) Afforestation :

The primary way to control soil erosion is to plant many trees and grasses, which give cover to the exposed dry land.

(2) Controlled Grazing :

The number of cattle to be grazed on slopes should be according to the carrying capacity of the pastures.

(3) Terraced agriculture :

Slopes must be cut into a series of terraces for cultivation so as to slow down the flow of rainwater.

(4) Contour ploughing :

Contour ploughing, terracing and building is done to check soil wash on slopes. Ploughing is done at right angles to the hill slopes.

(5) Construction of river dams :

River dams are built in the upper course of rivers to control floods and check soil erosion.

(6) Crop rotation :

A crop rotation system be applied and the land should be allowed fallow for some time. Soil fertility can be maintained in this way.

(7) Other methods :

In areas of heavy rain, basin type of cultivation be adopted. Tall trees should be grown as windbreaks and shelter belts in areas of strong winds. Roads, buildings and houses should not be constructed along the slopes.

WBBSE Notes for Class 6 Junior School Geography

Chapter 10 India – Tribes Of India Introduction :

Tribes:

Our motherland India is a homeland of a large number of indigenous or native inhabitants who are not touched by the way of living of the modern world. India has the largest population of such people (about 84-4 million in the world) who are commonly called ‘tribes’.

Tribes :

‘Tribes’ are specific social groups who have lived by hunting, animal rearing, and food-gathering since ancient times. They are also known as ‘Adivasis’. Their lives depend entirely on nature.

They are the poorest and perhaps the most backward population of our country. Nowadays, their life has changed a lot. The young generation works in the field or factory. Some of them are working in the town after completing their education.

Tribes of India :

Many tribal people live in different parts of India. Some of the major tribal groups in India include Gonds, Bhils, Santhals, Munda; Garos, Khasis, Chenchu, Kinnaur, Todas, Bhutias, and Jarawas (Andamanese). All of these tribal people have their own culture, tradition, language, and lifestyle.

Gonds :

Gonds are the largest tribal groups in India and one of the largest in the world. They are mostly found in the ‘Gond forests’ of Central India, Madhya Pradesh, Chhattisgarh, Telangana, and Andhra Pradesh. They practice sedentary agriculture. They are largely influenced by the Hindus and follow Hindu cultural traditions.

Bhils:

Bhils are the second largest tribal group in India. They are popularly known as the bowman of Rajasthan. They are also found in Madhya Pradesh and Gujarat. Their language is the Indo-Aryan language ‘Bhili’.

Earlier hunting was their chief occupation but cultivation is their main livelihood at present. They are known for their truthfulness and simplicity.

Santhals:

Santhals are the third largest tribal group in India. They are mostly found in the states of West Bengal, Jharkhand, Odisha, Bihar, and Assam. They speak the ‘Santhali’ language.

They have an ‘Olchiki’ script. They also speak Hindi, Oriya, and Bengali. The Santhals fulfill their basic needs from the plants and trees in the forest. Their other occupations are hunting, fishing, and cultivation.

Munda :

‘Munda’ generally means the ‘headman of the village’. They inhibit the region of Jharkhand but are also found in West Bengal, Bihar, Odisha, and Chhattisgarh. Their chief occupation is hunting.

Garos :

They inhibit Garo hills in Meghalaya. They speak the ‘Garo language’.-They are engaged in shifting cultivation, hunting, and fishing.

Khasi :

They are found in Khasi, Jayantia hills in Meghalaya, and also in the states of Manipur, West Bengal, Uttar Pradesh, Punjab, and Jammu And Kashmir. They speak the ‘Khasi’ language. Music plays an important part in their life.

Chenchu :

They inhibit the Nallamalai hills of Andhra Pradesh. They speak chenchu and Telegu languages. Primarily their occupation is hunting and food gathering. They worship a number of deities. Some of them also follow Hindu culture and tradition.

Kinnaur:

They are the tribes of Himachal Pradesh. They speak the Kinnauri language. They are mostly engaged as animal rearers.

Todes:

Todas are the tribes of the Nilgiri hills of Southern India. They speak Toda and Tamil languages. Their main occupation is animal rearing.

Bhutia :

Bhutias are of Tibetan origin. They are found in the northern part of Sikkim. They speak Sikkimese, Nepali, Bhutia, Lepcha, Hindi, and English languages. Their main occupation is agriculture. Some of them are herdsmen.

Jarawas :

Jarawas are the native people of South Andaman. They speak the Andamani language. Hunting, fishing, and food-gathering are their main occupation.

The language is spoken by people in different states of India :

There is great diversity in the languages of India. This is due to the huge size of the population in India. Different racial groups maintain their own languages in different regions but there,is not much difference in the scripts of many of these languages.

The languages of India have the following common features :

• All the Indian languages are phonetic in nature.
• All the Indian languages have more or less a common structure.
•  All the Indian languages have a large common vocabulary.

The languages spoken by the people of India have been divided mainly into the two groups—

• Indo-European Family (Arya) and
• Dravidian Family (Dravida).

The other two groups are

• Austric Family (Nightshade) and Sino-Tibetan Family (Kirata).

The following major languages have been specified in the eighth schedule of the Indian Constitution—

1. Assamese
2. Bengali
3. Gujarati
4. Hindi
5. Kannada
6. Kashmiri
7. Marathi
8. Malayalam
9. Oriya
10. Punjabi
11. Sanskrit
12. Tamil
13. Telegu
14. Urdu
15. Sindhi
16. Manipuri
17. Nepali
18. Boro
19. Maithili
20. Dogri
21. Santhali
22. Konkani.

State	Main language
1. Andhra Pradesh	Telegu, Urdu
2. Arunachal Pradesh	Mizi, Monpa
3. Assam	Assamese
4. Bihar	Hindi, Bhojpuri
5. Chhattisgarh	Hindi
6. Goa	Konkani, Goanese
7. Gujarat	Gujrati, Sindhi
8. Haryana	Punjabi, Hindi
9. Himachal Pradesh	Hindi
10. Jammu and Kashmir	Kashmiri, Urdu
11. Jharkhand	Hindi
12. Karnataka	Kannada
13. Kerala	Malayalam
14. Madhya Pradesh	Marathi, Hindi
15. Maharashtra	Marathi, Hindi.
16. Manipur	Manipuri
17. Meghalaya	Khasi, Garo
18. Mizoram	Mizo, English
19. Nagaland	Nagamese, English.
20. Odisha	Oriya
21. Punjab	Punjabi
22. Rajasthan	Rajasthani, Hindi
23. Sikkim	Lepcha, Nepali
24. Tamil Nadu	Tamil
25. Telangana	Telegu, Urdu
26. Tripura.	Bengali
27. Uttar Pradesh	Bhojpuri, Hindi, Urdu
28. Uttarakhand	Hindi
29. West Bengal	Bengali, Hindi

 

Union Territories	Main language
1. Andaman and Nicobar Islands	Hindi, Bengali, Nicobari
2. Chandigarh	Punjabi, Hindi
3. Dadra and Nagar Haveli	Villi, Gujarati
4. Daman and Diu	Marathi, Gujarati
5. Delhi (National Capital Territory)	Hindi
6. Lakshadweep	Malayalam
7. Puducherry	Tamil, French

 

The Languages Spoken by people in different States and Union Territories of India.

WBBSE Notes for Class 6 Junior School Geography

 

• Chapter 1 The Universe and Solar System Notes
• Chapter 2 Shape of The Earth: Is The Earth Around? Notes
• Chapter 3 Location of a Place on The Earth’s Surface Where You Are Notes
• Chapter 4 The Earth’s Motion The Earth Rotation Notes
• Chapter 5 Water – Land – Air Notes
• Chapter 6 The Ice-Capped Continent Antartica Notes
• Chapter 7 Weather And Climate Notes
• Chapter 8 Air Pollution Notes
• Chapter 9 Noise Pollution Notes
• Chapter 10 India
  • a. Location of India and Political Divisions Notes
  • b. Physical Geography of India Notes
  • c. Climate of India Notes
  • d. Soils of India Notes
  • e. Natural Vegetation of India Notes
  • f. Agriculture of India Notes
  • g. Tribes of India Notes
  • h. People of India Notes
• Chapter 11 – Maps

Chapter 11 Maps Introduction

Map:

Maps have become so much a part of our life that we cannot dispense with them. We often need them to find the location of a place. The most universal use of maps is for locating places and things.

If we do not know the right direction or the actual distance to reach a place where we want to go, a map can help us to capture all information available in that place making it easier to go to that place.

Maps can be and are of considerable use in planning the socio-economic development of a community, a region or a nation.

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

Map :

The word ‘map’ was originated from the Latin word ‘mappa’ which means a napkin or cloth. In ancient times, maps were drawn on cloth, leather or in cottony paper.

A map is an accurate drawing or representation of the whole or part of the earth’s surface on a flat surface such as paper according to a given scale. A map is a representation of selected features of a part of the Earth’s surface.

 

Maps are drawn to show the physical and cultural features of an area. A map gives us information about the places on the Earth’s surface in greater detail. Maps generally show the location of villages, cities, countries and continents.

Natural features like mountains, plateaus, plains, oceans, seas, lakes, rivers etc. are also indicated. Maps also indicate information about certain topics like temperature, rainfall, crops, minerals, industries, roadways, railways, population etc.

The most ancient map of the Earth was discovered in Babylon. This map was drawn on a terracotta plaque in 2500 B.C.

Main characteristics of a Map :

1.  A map is a representation of an area on a flat sheet of a paper.
2. Maps are drawn on a definite scale. Without scale, a map is simply a rough sketch.
3.  Maps are drawn with the help of lines of latitude and lines of longitude.
4. Maps have two dimensions-length and breadth.
5. Conventional signs and symbols are used to show the various features of the earth’s surface.
6.  A map has an index which explains the symbols, colours and letters used in the map.

Importance of Map :

Maps are the major tools of geography. Maps serve as a key to geography. Maps are becoming useful in many fields-

1. Maps are of vital importance for geographers.
2. An easier way to get information about the earth is the map.
3. The modern warfare has been guided by maps.
4. Maps guide travellers and tourists to reach their destinations.
5. Maps are necessary for administrators and politicians to run the state administration.
6. Maps are useful for different means, of transportation as they guide the rail, road, sea and air routes.
7. Maps are useful for students, teachers, industrialists, economists, historians, engineers and merchants.
8. One can now produce a map sitting in a room by getting pictures from satellites through computers.

 

A map is therefore more widely used as a tool for learning geography.

Disadvantages of Map :

Maps North direction has a few disadvantages also. A flat map cannot show the features of a round surface accurately. The shapes and sizes of the continents and oceans get distorted, especially around the poles. Thus’ every map has some distortions.

The key elements of a map :

A perfect map should have the following elements or essentials :

Types of Map :

There are different types of maps.

Generally, maps are of the following types :

(1) Physical or Relief map :

Maps showing natural features of the earth such as mountains, plateaus, plains, deserts, oceans, seas, lakes, rivers, forests etc. are called ‘physical’ or ‘relief’ maps.

(2) Political maps :

Maps showing countries, states, districts, cities, towns, villages and others with their boundaries are called ‘political maps’.

(3) Thematic maps :

Thematic maps are those maps which show selected or specific themes and inform us about the topics like rainfall, crops, industries, minerals, roadways, railways, population etc.

In thematic maps use of specific colours, signs, symbols and letters are required. The index in the map explains the meaning of those specified symbols. Thematic maps are more useful than general maps.

Topographical Maps :

A large-scale map of a small area showing physical and cultural features.

Cadastral Maps :

Maps which show the details of roads, fields and property.

Atlas :

A collection of maps bound in a volume is called ‘Atlas’. The term was first used by Gerhard Mercator in 1578 in the title of a collection of maps. He titled it ‘Atlas’ after the Greek God Atlas’. In present times too, a book of maps is known as ‘Atlas’.

Cartography :

The art of making maps is called ‘Cartography’ or the science of map making is known as ‘Cartography’. It studies the methods and principles of map-making. It includes topographical maps, and aerial photographs also.

Globe :

A globe is a sphere and is the true mode of the earth. It is a small-scale spherical model of the earth, usually showing the main surface features, chief towns, and political boundaries. The shapes and locations of different continents and oceans, countries, physical features etc. are shown on a globe more or less accurately.

Like the spherical earth the globe is also a three-dimensional model of it.

1. A globe has to be rotated to see all the places on it.
2. Imaginary lines called parallels of latitude running from east to west to encircle the globe and there are imaginary lines drawn from north to south poles called meridians of longitude.
3. Globes are big and round and cannot be carried easily from place to place.
4. Distance cannot be measured on a globe because it is a curved surface.
5. Globe is best suited to represent the whole earth.

importance of Globe :

1. Globes are the aids of a geographer to represent the earth’s surface.
2. A globe is a true model of the earth and is more accurate.
3. Globe helps in understanding the correct shape and sizes of continents and oceans.
4. With the aid of a globe, it is easily possible to understand the location of the countries.

Limitations of Globe :

Even though the globe is a small model of the earth so it is not possible to get much information about any country or continent.

1. It is difficult to carry a globe to all places.
2. A globe cannot show the minute details as could be shown on a map.
3. At a time the whole earth cannot be studied from a globe.

The difference between a map and a globe :

Map	Globe
1.    A map is a conventional drawing of an area drawn on a flat sheet of paper.	1.    A globe is a sphere and is the true model of the earth.
2.    Maps can be shown a large number of details.	2.    Globes do not show a large number of details.
3.    Maps can be easily handled.	3.    Large globes are difficult to handle.
4.    Map is more useful than a globe.	4.    Globe is more accurate.
5.    Distance can be measured on a map.	5.    Distance cannot be measured on a globe because it is a curved surface.
6.    At a time, the whole earth can be studied from a map.	6.    The whole earth cannot be studied from a globe. At a time, only one hemisphere can be studied.

 

Scale :

Scale is a map-land ratio. A scale is a ratio of the distance between any two points or places on the map and the actual distance between the same two points or places on the ground.

Example :

If a map has a scale of 1 cm: 5 km, it means that one centimetre on the map represents a distance of 5 kilometres on the ground.

The necessity of scale :

1. Scale is the most important essential of a map. Without scale, we have only a sketch or a diagram and not a geographic map.
2.  It is necessary to draw a scale to show the relative positions of a different places on the map.
3. Every map has a definite ratio to the earth. It is not possible to make a map of the same size because 25000 miles or 40000 km of paper will be required to draw the equator.
4. Maps are generally reduced in size. They are said to be “drawn to scale”. Thus scale is a necessity in the drawing of a map.

Importance of Scale :

Scale is the most important item of the study of maps.

1. With the help of the scale, we can represent large areas in a reduced shape and size.
2. Without a scale, a map is simply a diagram or a sketch. A map is meaningless without scale.
3. We can measure the distance between two points on the map without going to the field.
4. A map can be reduced or enlarged with the help of a scale.

Types of maps on the basis of scale :

Generally, maps are of two types on the basis of scale. There are ‘small-scale maps’ and ‘large-scale maps’ used to show larger or smaller ground distances.

Small-scale maps :

Maps which show larger regions like the whole world, continent and countries are called ‘small scale maps’. These maps show greater distances in a smaller map. The scale of such a map may be 1 cm = 250 km.

or 1 cm in the map distance = 250 km. on the ground distance. Minute details of any region cannot be shown on such maps.

Large-scale maps :

Maps which show smaller regions like a part of a country, cities or villages are called ‘large scale maps’. These maps show lesser distance in a larger map. The scale of such a map may be 1 cm = 5 km.

or 1 cm. in the map distance = 5 km on the ground distance. These maps show detailed information of smaller areas.

Distinguish between small-scale maps and large-scale maps :

Small Scale Maps	Large Scale Maps
1.    Small scales are scales of miles to inches or kilometres to centimetres.	1.    Large scales are scales of inches to the miles or cm to the kilometre. The smaller the number of miles, the larger is the scale.
2.    For example 1 cm: 10 km. 1 inch: 60 miles	2.    For example 10 cm: 1 km.                                               6 inches: 1 mile.
3.    In this, 1 cm shows a distance of more than 1 Km.	3.    In this, 1 km is shown by a length of more than 1 cm.
4.    Atlas maps and wall maps are on small scales.	4.    Cadastral maps are on large scales.
5.    These maps do not show details of an area.	5.    These maps show details of an area.
6.    These are called small scale due to the smaller size of the map.	6.  These are called large scale due to the larger size of the map.
7.    If R. F. is given, the small scales have a  larger denomination such as— 1: 50,000,000.	7.    If R.F. is given, the large scales have the smaller denomination such as – 1: 50,000.

 

Directions :

Direction is indispensable for the accurate determination of the location of a place. It is, therefore, a very important part of the map. The two ends of the axis of the earth are known as ‘The North Pole’ and ‘South Pole’.

A line joining the north-pole and south-pole is called a true ‘North-South’ line. A line cutting the North-South line at right angles shows the East-West direction. The sun rises in the East and sets in the West.

Thus North-South, East and West are the four major directions. These major directions are called ‘Cardinal points’. Other minor directions can be obtained by bisecting these angles.

Importance of Directions for maps :

Direction is the fundamental essence of a map. Without direction, a map is meaningless. Direction is shown by an arrow pointing towards ‘North’ at the top of the map. Direction helps in the setting of a map.

Aircraft pilots, navigators, travellers, and tourists, follow their routes with the help of directions. Military movements are also guided by directions of the maps. For surveying an area, the direction is of vital importance. Thus a map must represent the major directions.

Sign and Symbols :

The topographic map contains a variety of information about physical features and cultural features. These are given by using signs and symbols in various letters and colours so that the clarity of the map is maintained. In thematic maps use 6f specific colours, signs, symbols and letters are required.

Conventional Sign and Symbol :

Conventional signs are the symbols used to show different features on the maps. These symbols are recognised all over the world.

These symbols are very useful in understanding the features of the lands shown on the maps. Towns, villages, buildings, railway lines, roads, trees etc. are big features, it is extremely difficult to draw on a map the actual shape and size of these features.

Therefore, we use various symbols to show them on the map. All the countries use the same symbols for a particular feature. These are called ‘convectional symbols’ or ‘convectional signs’. All maps of the world use specific colours, signs, symbols and letters to denote universal meaning.

These are called ‘convectional signs and symbols’. Rivers, lakes, seas, oceans and other water bodies are shown in blue colour. Areas coloured green show forests, parks and grasses Yellow colour is used to show cultivated lands. Brown colour for hills and mountains. These are drawn at the bottom of topographical maps. These form the key of map-reading.

Index :

The index is useful for locating places on the maps. It explains the symbols, colours and letters used in the map. In thematic maps use of specific colours, signs and letters are required.

The index in the map explains the meaning of those specified symbols. Atlas contains an index of place names at the end. Names are arranged alphabetically in the index. Map or page number, latitude and longitude references are given for each place.

Sketch :

A sketch is a rough map of an area without scaj£. The main idea of drawing a sketch is to convey the locational information easily with the help of landmarks like the post office, cinema hall etc.

 

 

It shows directions only. Since a sketch is not drawn according to a scale, the distance cannot be correctly understood. So, we can get only a general idea about a place or region by a sketch.

Plan :

A plan is a detailed map of a small area on a large scale. A plan is drawn accurately to depict a small area like a room, a house, a classroom, a school etc. After proper measuring, the plan is drawn according to the specified scale.

 

So ‘distance’ and ‘direction’ can both be understood by a plan. Plans are drawn on a large scale, such as one centimetre shows one metre or one inch shows ten feet etc.

The difference between a map and a sketch :

Map	Sketch
1.    A map is a conventional picture of an area drawn on a flat sheet of paper.	1.    A sketch is a rough map of an area without scale.
2.    A map is drawn to scale.	2.    A sketch has no scale.
3.    A map can show a big area.	3.    A sketch can show a small area.

 

The difference between a map and a Plan :

Map	Plan
1.    A map is a conventional drawing of an area drawn on a flat sheet of paper.	1.    A plan is a detailed map of a small area on a large scale.
2.    A map shows a large area on a small scale.	2.    A plan shows a small area on a large scale.
3.    A map shows only important features.	3.    A plan can show many details.

 

The difference between a plan and a sketch :

Plan	Sketch
1.    A plan is a detailed map of a small area on a large scale.	1.    A sketch is a rough map of an area without scale.
2.    Plans are drawn on a large scale.	2.    A sketch map is drawn without scale.
3.    ‘Distance’ and ‘direction’ both can be understood by a plan.	3.    It shows ‘directions’ only.
4.    A plan can show a small area in great detail.	4.    It is useful for locating various parts of a town or of a small area.

 

WBBSE Notes for Class 6 Junior School Geography

The People Of India :

There is great diversity in different people of India. Different people of India have different festivals, songs, and dance forms, folk culture, traditions, etc.

India Is A Secular Country :

India is a secular country. People belonging to different religions and have their own regional faiths. Hindus, Muslims, Sikhs, Jains, Buddhists, Parsis, Christians, etc. live here together.

People of primitive social groups who worship natural things like trees, animals, rocks or stones are also live here and celebrate all their religious faiths with equal enthusiasm.

Some Religious Festivals Of India :

Different religious festivals like:

 

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

India’s National Days :

All Indians observe the ‘National Days together with reference to the 15th of August ‘Independence Day’, the 26th of January—Republic Day, and the 2nd of October—the birthday of Mahatma Gandhi, The ‘Father of the Nation’.

As Indian, we gather in public places or in our schools, colleges, and other institutions to pay tribute to our motherland, our freedom fighters, and great leaders.

Unity in Diversity :

There are many languages, many ideas, and many clothes in India, but there is a great unity amongst such diversity. We have only one identity— all are Indians.

So, despite differences in languages, religions, and culture we form bonds with our nation out of love and patriotism. On any achievement in the field of science and literature or entertainment or victories in sports, all Indians feel equally happy and proud.

We all get distressed whenever a part of our country faces a crisis. We all celebrate all festivals together. In conclusion, it may be said that in our country there is ‘Unity in Diversity’.

WBBSE Notes for Class 6 Junior School Geography

Chapter 10 India – Climate Of India Introduction :

Climate Of India:

India has a great diversity of climates. There are great variations in climates from region to region because India has a variety of temperatures, rainfall, air pressure etc. in its various region.

Nevertheless, there is a similarity in all these varieties, the impact of the monsoon winds in all parts of the country. Hence, it is known as the ‘land of monsoon’. The word ‘monsoon’ is derived from the Arabic word ‘Mausim’ which means ‘season’.

The ‘Tropic of Cancer passes through the middle of the country. It clearly demarcates the country into the ‘tropical region’ to the south of it and the sub-tropical and temperate region to the north of it. Hence, the climate of India is broadly described as a ‘Tropical Monsoon’ type.

The Controlling Factors Of Indian Climate :

There are various factors which influence the climate of India. The factors that indicate a dominant influence on the climate of India are as follows :

1. Latitude

Read and Learn  More WBBSE Notes For Class 6 Junior School Geography

Latitudinally, India extends from 8°04′ north latitude in the south to 37°06′ north latitude in the north. So, India belongs to the ‘Torrid Zone’. The ‘Tropic of Cancer’ (23°30′ north latitude) passes through the middle of the country.

So, a hot and humid Tropical climate prevails in South India and a cold and temperate climate prevails in North India.

2. Altitude

The altitude of the land plays an important role in the variation of temperature. It is due to the higher altitude of the northern mountains they are colder than plain regions.

In the Deccan plateau, temperatures remain relatively low in the summer months though it lies in the Torrid Zone. It is because temperature decreases with increasing altitude.

3. Location of Mountain :

The transverse location of the lofty Himalayan Mountains forms a barrier which affects the climate of India such as follows :

•  It helps to trap the Monsoon wind forcing them to shed their moisture which gives plenty of rain in summer within the country.
• It prevents the cold winds of North Asia from blowing into India and protects it from the severe cold wind in winter.

4. Wind

India has a monsoon climate. Monsoons are land breezes and sea breezes on a large scale. As the winds blowing over the Indian sub-continent reverse their directions seasonally, they are known as ‘Monsoon winds’.

The southwest monsoon and the northeast monsoon play the most important role in formulating the climatic characteristics of our country. For their profound influence over the climate of India, the country is called ‘the land of Monsoon’.

In summer, the monsoon winds blow from sea to land as South-West monsoon heavy rainfall occurs. In winter, the monsoon blow from sea to land as South-West monsoon heavy rainfall occurs. In winter, the monsoon winds blow from land to sea as North-East Monsoons and these dry winds occur a little rainfall.

5. Distance from the sea :

Places quiet away from the sea (areas in the interior) have a-higher relative diurnal and annual ranges of temperature. So, they experience an extreme or continental type of climate.

Such as Delhi, Ludhiana etc. of North-west India. But the places situated in coastal areas experience equable maritime climates. Their annual range of temperature is minimum. Mumbai, Chennai, Thiruvananthapuram and other coastal regions experience the influence of the sea, thereby, having a moderate temperature.

The Climatic Characteristics Of India :

Climate India is a ‘Tropical Monsoon’ type. The characteristics of the Indian climate are as follows :

1. The climate of India is mainly influenced by Monsoon winds and the Himalayas.
2. The nature of the monsoon climate is hot and humid. In India, the summer is hot and humid.
3. Most of the rain is received from South-West Monsoons during the period of mid-June to mid-September. It is seasonal rainfall.
4. India is noted for its diversity of rainfall. The rainfall is unevenly distributed over the country.
5. Winter is mild and dry. Most of the rainfall (more than 85%) is received in summer.
6. Summer rainfall is uncertain due to the ‘gambling of the monsoons’. Sometimes monsoons start early or occurs heavy rainfall in a short time resulting in floods. On the other hand, often the onset of monsoon is delayed resulting in drought. The early or late retreat of monsoons also results in serious droughts.
7. The amount of rainfall is determined by the presence of mountains.
8. Most of the areas of India have variable rainfall as much as 30 cm plus or mountains.
9. While Mowsinram-Cherapunji receives more than 1200 cm of rainfall, the northern part of India is cooler compared to the southern part.
10. On a summer afternoon the ‘Thar Desert’ of Rajasthan may be 50°C while on a winter night in the Ladakh plateau, it is – 40°C.

The Climatic Regions Of India :

The climate is the aggregate of atmospheric conditions over a wide area for a long period of time (say at 35 years). The natural division of the Earth according to the distinctive characteristic features of climate is called a ‘Climatic Region’.

Koppen, Thorthwaite, Kendrew, Stamp, Miller etc. have attempted to classify India into different climatic regions. Of these, Koppen’s classification seems to be the most acceptable and following it Indian climatic regions are presented here.

1. Tropical and sub-tropical Humid Monsoon climate :

This kind of climate is found in Ganga and Sutlej plains, the Brahmaputra valley and parts of the Central Plateau and Highland region.

2. Arid Climate :

The Desert or Marusthali region of Rajasthan is included in this climatic region.

3. Semi-Arid Climate :

This kind of climate prevails in the Rohi and Bagar areas of Rajasthan, the southern part of Punjab and Haryana and the rain-shadow area of Maharashtra and Karnataka.

4. Tropical Savanna climatic region :

This kind of climate occurs in Gujarat, Maharashtra, Central and Southern Madhya Pradesh, Chhattisgarh, Andhra Pradesh, Telangana, West Tamil Nadu, Jharkhand and South-western West Bengal.

5. mountain climate or cold Mountainous region :

The High altitudes of the Western Himalayas including Kashmir and Ladakh fall within this climatic region.

6. Tropical West Climate :

This kind of climate prevails in the Konkan and Malabar coasts where the average annual rainfall is 300 cms or more and temperature varies between 18°C and 27°C.

Seasons in India :

Monsoon winds dominate the climate of India. India has a broad unity of Tropical Monsoon type of climate. The monsoon type of climate is characterised by distinct seasonality.

Based on the arrival and departure of monsoon winds, rainfall, temperature and air pressure, the Meteorological Depart, of the Government of India has divided the climate of India into four seasons, which rotate in a cycle as follows :

(1) The hot weather season or summer.	March to May
(2) The southwest Monsoon season or the rainy season.	June to September
(3) The season of retreating monsoon or Autumn.	October to November
(4) The cold weather season or winter.	December to February

 

The Hot Weather season or summer

Summer is the season previous to the arrival of the southwest monsoon winds. From March to the end of May or mid-June is the hot season or summer in India.

Temperature

A rapid increase in temperature is witnessed because the sun moves northwards and shines vertically near the ‘Tropic of Cancer’. The average temperature is above 30°C.

May is the hottest month of this season in India. In the month of May, the temperature rises to 40°C. In Kolkata, the average daytime temperature maximum reaches to 35°C in the month of May.

Pressure and wind

The summer is a period of rising temperature and decreasing air pressure conditions of low pressure develops over north-west and central India. Local violent storms occur during April-May.

They approach from the northwest accompanied by thunder and torrential rain, hence they are known as ‘Nor-westers’. They are locally, especially in West Bengal are called ‘Kalbaishakhi’ (i.e. the disaster of the month of Baisakh).

In the coastal region of South India, especially in the western coastal region of Kerala and Karnataka, the local storms are known as ‘Mango Showers’. In summer, a hot dry wind blows in the north-western parts of India.

It is known as ‘Loo’. It is very common in Punjab, Haryana, Uttar Pradesh and Bihar. Sometimes a hot dry wind accompanied by dust storms in North-West India, especially in the desert area of Rajasthan occur in the afternoon are locally known as ‘Andhi’.

Rainfall :

Most of the country is dry in the pre-monsoon period. But there are some areas, especially on the coastal areas of south India receive convectional rainfall. The west coast also starts receiving rainfall with ‘mango showers’.

Thunder shower known as ‘Kalbaishakhi’ in West Bengal and ‘Bardai Chhila’ in Assam are also bring some rainfall which decrease temperature locally.

Rainy Season (June to September)

The rainy season lasts from June to September. The southwest monsoon generally blows from June to September. They bring rain. For this reason, the season is known as the southwest monsoon or Rainy Season.

Temperature :

On the 21st June, the sun shines vertically over the ‘Tropic of Cancer’. Therefore, temperatures are high (more than 30°C). With the onset of monsoon, there is a drop in temperature (5°C to 30°C). With a result, June or July is not the hottest month.

Pressure and Wind :

During this time, though the landmass gets heated to a very great extent, an area of very low pressure develops over the Indian subcontinent.

This low-pressure zone attracts the southeast trade wind which on crossing the equator becomes southwest monsoon winds (according to Ferrel’s law) and arrives the western coasts of India all of a sudden with furious speed and violent thunder and lightning. The advent of these violent winds is known as the ‘Burst of Monsoon’.

On reaching the Indian sub-continent they are divided into two branches-

(1) The Arabian sea branch and
(2) Bay of Bengal branch.

Rainfall:

South-west monsoons are rain givers as most of the subcontinent gets rainfall in this season. The Arabian sea branch gives heavy rainfall on the west coast, but Deccan Plateau lies in the rain-shadow are of the Western Ghats.

The Bay of Bengal branch gives heavy rainfall to the southern slopes of the Himalayas and the Meghalaya Plateau (Garo, Khasi hill etc.) Mowsinrarrtgaon near Cherapunji receives the highest rainfall (about 1250 cm) in the world.

But Shillong lies in the rain-shadow area of the Meghalaya plateau (Khasi hill). Monsoon winds after descending down the slopes give less rainfall at Shillong. Except for the desert of the North-West, the rest of India receives rainfall varying between 60 – 200 cm. 80% of rainfall occurs in the rainy season. Rainfall is mostly (80%) orographic in nature.

The Season of Retreating Monsoon or Autumn (October-November) :

This is the period of transition between the final withdrawal of the southwest monsoon and the regular setting of the northeast monsoons.

Temperature :

The sun beings to move towards the equator. There is a decrease in temperature in north India. Hot and sticky Weather is found in other parts of India.

Pressure and Wind:

South-west monsoons begin to withdraw from the subcontiniÿ’Siurfhgÿtiÿe’1ÿ’ week of October. Some tropical cyclones are developed particularly on the coastal strip of the Bay of Bengal. In West Bengal, these cyclones are locally known as ‘Aswiner Jhar’.

Rainfall :

Heavy rainfall occurs in coastal areas. Cool weather begins in NorthWest India, But the southern parts of India have an equable climate.

The Cold Weather Season (Winter)

The cold season or winter lasts from December to February.

Temperature:

On the 22nd of December, the sun is overhead at the ‘Tropic of Capricorn’ arid the temperature in north India becomes very low. January is the coldest month. The temperature decreases from south to north.

It varies from 10°C to 25°C. The average temperature of winter in North India varies from 10°C to 15°C while in South India it rises to 25°C. So, the southern parts of India have warm conditions while low temperatures (winter) are found in North and North West India.

Pressure and winds :

High pressure is developed over the North-West of India while a low pressure exists over the Indian Ocean with a result of winds blowing from land to sea (Ocean). The outflowing winds are Westerly in Northern plain and North-Easterly over the rest of the country.

Rainfall :

The North-East Monsoon wind is very dry. So, it does not give sufficient rainfall in India but causes snowfall on the higher altitudes of the Himalayas. The North-East monsoon winds pick up some moisture while crossing the Bay of Bengal and give rain to the South-East coast of India, especially in the Coromandel Coast of Tamil Nadu.

During winter, the stable conditions of weather in North-West India are disrupted by a series of shallow cyclonic disturbances from the Mediterranean Sea.

These are known as ‘Western Disturbances’, which also bring a small amount of rainfall (10 to 20 cms) in North and North-West India. Such winter rainfall is beneficial to wheat cultivation, especially in North-West India.

The Influence of Monsoon on Indian Climate:

South-West Monsoon wind gives rain in India, but this wind is irregular and uncertain. Some years it arrives early, some years late. Sometimes rainfall occurs continuously for a few days. Sometimes, it is rainless for a long time.

Excessive rain causes floods and lack of-rain causes droughts. As a result droughts and floods are common in India. Monsoon wind is seasonal. So, Indian rainfall is seasonal.

Due to the uneven distribution of rainfall Indian climate is not similar all over India during the same time. The. states of Assam, West Bengal and Bihar experience floods while drought occurs in Gujarat and Rajasthan.

The Influence of Monsoon on India’s Agriculture:

Indian agriculture and economy is mostly dependent on monsoon rainfall as well as South-West-Summer monsoon winds. The summer crops on Kharif crops are dependent on monsoons. Good rains have resulted in bumper crops productions.

The uniform distribution of rain results in multiple cropping. Heavy rainfall leads to devastating floods that cause crop failure. Scanty rainfall may cause extensive drought conditions when no crops can be produced.

WBBSE Notes for Class 6 Junior School Geography