Chapter – 1
THE EARTH IN THE SOLAR SYSTEM
Celestial bodies-
- Shining objects in the sky like Sun, Moon; made up of gases; own heat and light (stars, e.g. Sun)
Constellations-
- Various patterns formed by different groups of stars
Pole Star-
- North star indicates the north direction
Planets-
- Do not have their own heat and light; lit by the light of the stars
Asteroids
- Tiny bodies which also move around the sun.
- between the orbits of Mars and Jupiter
Meteoroids
- The small pieces of rocks which move around the sun
- Sometimes these meteoroids come near the earth and tend to drop upon it.
- During this process due to friction with the air they get heated up and burn.
- It causes a flash of light.
- Sometimes, a meteor without being completely burnt, falls on the earth and creates a hollow.
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The Sun
- Centre of the solar system
- Made up of extremely hot gases
- Provides the pulling force that binds the solar system
- Ultimate source of heat and light for the solar system
- About 150 million km away from the earth
Planets (8 planets)
- MY VERY EFFICIENT MOTHER JUST SERVED US NUTS
- Move around the sun in fixed paths (paths- elongated)- orbits.
- Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.
- Till recently (August 2006), Pluto was also considered a planet.
- However, in a meeting of the International Astronomical Union, a decision was taken that Pluto like other celestial objects (Ceres, 2003 UB313) discovered in recent past may be called ‘dwarf planets.”
The Earth
- 3rd nearest planet to the sun.
- In size- 5th largest planet.
- It is slightly flattened at the poles (Geoid shape)
- 2/3rd surface is covered by water (blue planet)
The Moon (Earth’s satellite)
- Diameter -one-quarter that of the earth.
- The moon moves around the earth in about 27 days.
- Neil Armstrong was the first man to step on the surface of the moon on 21 July 1969.
- Whitish broad band, like a white glowing path across the sky on a clear starry night i.e. cluster of millions of stars (Milky)- Akash Ganga
- A galaxy is a huge system of billions of stars, and clouds of dust and gases.
- A Satellite is a celestial body that moves around the planets in the same way as the planets move around the sun.
- Benefits- To gather information and communication.
- Examples- INSAT, IRS, EDUSAT, etc.
Chapter- 2
GLOBE : LATITUDES AND LONGITUDES
Latitude
- Parallels of latitudes- parallel circles from the equator up to the poles
- Chandrapur, Maharashtra (India) is situated at 20° N latitude and Belo, Brazil (South America) Horizonte is situated at 20° S latitude.
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Lines of references are called the meridians of longitude
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Tonga Islands (in the Pacific Ocean) and Mauritius Islands (in the Indian Ocean) are situated on the same latitude (i.e., 20° S)
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- Unlike parallels of latitude, all meridians are of equal length
- Prime Meridian- Its value is 0° longitude and from it we count 180° eastward as well as 180° westward.
- The Prime Meridian and 180° meridian divide the earth into two equal halves, the Eastern Hemisphere and the Western Hemisphere
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- As the earth rotates from W-> E, those places east of Greenwich will be ahead of Greenwich time and those to the west will be behind it
- The earth rotates 360° in about 24 hours, which means 15° an hour or 1° in four minutes.
- Thus, when it is 12 noon at Greenwich, the time at 15° east of Greenwich will be 15 × 4 = 60 minutes, i.e., 1 hour ahead of Greenwich time, which means 1 p.m.
- But at 15° west of Greenwich, the time will be behind Greenwich time by one hour, i.e., it will be 11.00 a.m. Similarly, at 180°,
India
- In India, the longitude of 82½° E (82° 30'E) is treated as the standard meridian (Indian Standard Time (IST))
- India located east of Greenwich at 82°30'E is 5 hours and 30 minutes ahead of GMT.
- So it will be 7:30 p.m. in India when it is 2:00 p.m. noon in London
- The earth has been divided into twenty-four time zones of one hour each. Each zone thus covers 15° of longitude
- Russia- 11 zones
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Chapter- 3
MOTIONS OF THE EARTH
- Rotation is the movement of the earth on its axis.
- The movement of the earth around the sun in a fixed path or orbit is called Revolution.
- The axis of the earth which is an imaginary line, makes an angle of 66½° with its orbital plane.
- The circle that divides the day from night on the globe is called the circle of illumination.
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Chapter- 5
MAJOR DOMAINS OF THE
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The climbers experience problems in breathing due to this decrease in the density of air
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Continents
Asia-
- Largest continent; It covers about 1/3rd of the total land area of the earth.
- The continent lies in the Eastern Hemisphere.
- The Tropic of Cancer passes through this continent.
- Asia is separated from Europe by the Ural mountains on the west
- The combined landmass of Europe and Asia is called the Eurasia (Europe + Asia).
Europe-
- The Arctic Circle passes through it.
- It is bound by water bodies on three sides.
Africa-
- 2nd largest continent after Asia.
- The Equator or 0º latitude runs almost through the middle of the continent; large part of Africa lies in the Northern Hemisphere.
- It is the only continent through which the Tropic of Cancer, the Equator and the Tropic of Capricorn pass.
- The continent is bound on all sides by oceans and seas.
- world’s longest river the Nile, flows through Africa.
North America-
- 3rd largest continent; It is linked to South America by a very narrow strip of land called the Isthmus of Panama.
- The continent lies completely in the Northern and Western Hemisphere.
- Three oceans surround this continent
South America-
- Lies mostly in the Southern Hemisphere.
- The Andes, world’s longest mountain range, runs through its length from north to south
- World’s largest river- Amazon.
Australia
- smallest continent
- lies entirely in the Southern Hemisphere
- surrounded on all sides by the oceans and seas (island continent)
Antarctica-
- Completely in the Southern Hemisphere
- The South Pole lies almost at the centre of this continent.
- Located in the South Polar Region
- Many countries have research stations in Antarctica.
- Eg. India- Maitri and Dakshin Gangotri
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Chapter- 6
MAJOR LANDFORMS OF THE EARTH
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Chapter- 7
OUR COUNTRY – INDIA
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Chapter- 8
INDIA : CLIMATE, VEGETATION AND WILDLIFE
Broadly, the major seasons recognised in India are-
- Cold Weather Season (Winter) December to February
- Hot Weather Season (Summer) March to May
- Southwest Monsoon Season (Rainy) June to September
- Season of Retreating Monsoon (Autumn) October and November
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COLD WEATHER SEASON OR WINTER
- Sun rays do not fall directly in the region.
- Temperatures are quite low in northern India.
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HOT WEATHER SEASON OR SUMMER
- Sun rays more or less directly fall in this region.
- Temperature becomes very high.
- Hot and dry winds called loo, blow during the day.
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SOUTH WEST MONSOON SEASON OR RAINY SEASON
- Marked by the onset and advance of monsoon.
- The winds blow from Arabian Sea and Bay of Bengal towards the land.
- They carry moisture with them.
- When these winds strike the mountain barriers, rainfall occurs.
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SEASON OF RETREATING MONSOONS OR AUTUMN
- Winds move back from the mainland to the Bay of Bengal.
- This is the season of the retreating monsoons.
- The southern parts of India, particularly Tamil Nadu and Andhra Pradesh receive rainfall in this season.
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NATURAL VEGETATION
TROPICAL RAIN FOREST-
- Heavy rainfall.
- So dense that sunlight doesn’t reach the ground
- Shed their leaves at different times of the year.
- Therefore, they always appear green and are called evergreen forest
- mahogany, ebony and rosewood
- Location- Andaman and Nicobar Islands, parts of North-Eastern states and a narrow strip of the Western slope of the Western Ghats
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TROPICAL DECIDUOUS FORESTS
- Large part of our country
- Also called monsoon forests.
- Less dense.
- They shed their leaves at a particular time of the year.
- Sal, teak, peepal, neem and Shisham.
- Madhya Pradesh, Uttar Pradesh, Bihar, Jharkhand, Chhattisgarh, Odisha, and in parts of Maharashtra.
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THORNY BUSHES
- Found in dry areas of the country.
- The leaves are in the form of spines to reduce the loss of water.
- Cactus, khair, babool, keekar
- Rajasthan, Punjab, Haryana, Eastern slopes of Western Ghats and Gujarat
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MOUNTAIN VEGETATION
- Found in the mountains according to the variation in height.
- With increase in height, the temperature falls.
- At a height between 1500 metres and 2500 metres most of the trees are conical in shape (coniferous trees)
- Chir, Pine and Deodar
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MANGROVE FORESTS
- Can survive in saline water.
- They are found mainly in Sunderbans in West Bengal and in the Andaman and Nicobar Islands.
- Sundari is a well-known species of trees in mangrove forests after which Sunderbans have been named
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WILDLIFE
- National animal- Tiger
- Gir forest in Gujarat is the home of Asiatic lions.
- Elephants and one-horned rhinoceroses roam in the forests of Assam.
- Elephants are also found in Kerala and Karnataka.
- Camels and wild asses are found in the Great Indian desert and the Rann of Kuchchh respectively.
- Wild goats, snow leopards, bears, etc. are found in the Himalayan region.
- Some birds such as Pintail Duck, Curlews, Flamingo, Osprey and Little Stint migrate to our country in winter season every year.