1 The Earth in the Solar System
- Sun, Moon and all those objects shinning in sky are called celestial bodies.
- Fortnight 14 days.
- Patterns formed in sky are called constellation.
- Ursa Major or Big Bear;
- Saptarishi (Seven sages) – Seven Stars – part of Ursa Major – most easily recognisable.
- North Star=Pole Star; find it with the help of saptarshi.
- Jupiter, Saturn, Uranus have rings (belts of small debris) can be seen from powerful telescope.
- Mercury, Venus, Earth, Mars Inner planets (rock made); Jupiter, Saturn, Uranus, Neptune
- planet(moons) = earth(1), mars(2), Jupiter(16), Saturn(18), Uranus(17),Neptune(8)
- Sun 150 Million Kms
- Mercury 88 days to revolve around the sun
- Venus – Earth's Twin(shape and size)
- Pluto – Dwarf planet (other dwarf planet ceres,2003 UB313)
- Earth – 5th largest planet ; Geoid shape earth like ; 2/3rd water covered – looks blue from outer space so BLUE Planet ; 150 million Km from sun
- Moon – 3.8 lakh Km from the earth; 27 days to revolve around earth and same time to complete to one spin so we see only one side of the moon; 1/4th diameter of earth.
- Milky way galaxy=Akash Ganga
- Earth<solar system<milky way galaxy<universe
- Meteoroids – rock pieces moving around the sun
- Asteroid found between mars and Jupiter - parts of a planet which exploded many years back.
2 Globe : Latitudes and Longitudes
- Globe is true model (miniature form) of the earth.
- Parallels of Latitudes – Parallel circles from equator up to the poles.
- Equator 0° latitude
- By measuring the angle of the pole star we can know the latitude if your place
- Tropic of cancer - 23½°N
- Tropic of Capricorn - 23½°S
- Arctic circle - 66½°N
- Antarctic circle - 66 ½° S
- Mid – day sun overhead at least once in year on all latitudes in between tropic of cancer and Capricorn
- Torrid zone – maximum heat; Temperate zone – moderate temperature; Frigid zones – very cold(sun never rises above the horizon)
- Prime meridian - 0° longitude passing through Greenwich where British Royal Observatory is located
- East of Greenwich ahead; west of it behind.
- 1° = 4 minutes; 15° = 15x4=60 min=1 hour (numerical)
- 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°, it will be midnight when it is 12 noon at Greenwich.
- Indian standard time (IST) 82½°E Standard Meridian of India; Russia 11 standard time zones.
- 1 hr 45 min time difference between local time of Dwarka in Gujrat to Dibrugarh in Assam.
- POINT ON MAP: Chandrapur MH (Ind), Belo Horizonte Brazil(S Amer), Dhubri in Assam, Tonga Islands (Pacific Ocean), Mauritius Island in (Indian Ocean)
3 Motions of the Earth
- Axis of earth makes 66½° with its orbital plane.
- Circle that divides the day from night is circle of illumination.
- Map – representation of earth surface or a part on the flat surface.
- Three types of maps
- Physical or relief map – mountains, plateaus, rivers, oceans
- Political map – cities, towns, villages, states, countries
- Thematic map - roads maps, rainfall maps, distribution of forests, industries
- Three components of maps
- Distance – Map(small scale);plan(large scale)
- Direction – cardinal points(east, east, north, south);intermediate directions (NE, NW, SE, SW)
- Symbols – conventional symbols ae internationally agreed use of symbols
- Sketch – rough drawing without scale
- Plan – drawing of small area on a large scale
5 Major Domains of the Earth
- Lithosphere – solid portion of earth-lithos means stones in Greek – 29% land
- Atmosphere – gaseous layer – atmos means vapour in Greek
- Hydrosphere – water surface –hudor means water - 71% water
- Biosphere – narrow zone where we find land, water, and air together which contains all forms of life –bios means life in Greek
- Two main divisions
- Land mass – continents
- Water bodies – ocean basins
- Mt.Everest – 8,848m above sea leavel
- Mariana Trench in pacific 11,022m deep
- Seven major continents
- ASIA – largest – 1/3rd – separated from Europe by Ural Mountain – tropic of cancer passes through it
- EUROPE – Arctic Circle passes through it.
- AFRICA – 2nd largest – equator runs through the middle of the continent – the only continent with TOCap, TOCan, Equator pass – world's largest hot desert Sahara desert – world's longest river Nile – all sides bound by seas and oceans
- NORTH AMERICA - 3rd largest – linked to south America through a narrow strip of land - panama isthmus
- SOUTH AMERICA – world's longest mountain range Andes – world's largest river Amazon
- AUSTRALIA – smallest continent – island continent – all sides water
6 MAJOR LANDFORMS OF THE EARTH
A hill is a land surface that rises higher than the surrounding area.
Generally, a steep hill with an elevation of more than 600 metres is termed as a mountain
landforms are a result of two processes
- the internal process leads to the upliftment and sinking of the earth's surface
- external process -the continuous wearing down and rebuilding of the land surface.
- wearing away of the earth's surface is called erosion. The surface is being lowered by the process of erosion and rebuilt by the process of deposition. two processes are carried out by running water, ice and wind
In some mountains, there are permanently frozen rivers of ice. They are called glaciers.
Few people live in the mountain areas. Since the slopes are steep, less land is available for farming
Mountains may be arranged in a line known as range. Many mountain systems consist of a series of parallel ranges extending over hundreds of kilometres. The Himalayas, the Alps and the Andes are mountain ranges of Asia, Europe and South America
There are three types of mountains- Fold
Mountains, Block Mountains and the Volcanic
Mountains. The Himalayan Mountains and the Alps
are young fold mountains with rugged relief and high
conical peaks. The Aravali range in India is one of the
oldest fold mountain systems in the world. The range
has considerably worn down due to the processes of
erosion. The Appalachians in North America and the
Ural mountains in Russia (Figure 5.1) have rounded
features and low elevation. They are very old fold
Block Mountains are
created when large areas are
broken and displaced
vertically. The uplifted blocks
are termed as horsts and the
lowered blocks are called
blocks are called
graben. The Rhine valley
and the Vosges mountain in
Volcanic mountains are
formed due to volcanic
activity. Mt.Kilimanjaro in Africa and Mt.Fujiyama
mountains are a
storehouse of water. Many rivers have their source in
the glaciers in the mountains. Reservoirs are made
and the water is harnessed for the use of people. Water
from the mountains is also used for irrigation and
generation of hydro-electricity. The river valleys and
terraces are ideal for cultivation of crops. Mountains
have a rich variety of flora and fauna. The forests
provide fuel, fodder, shelter gum, raisins
l sports like paragliding, hang gliding,
river rafting and skiing
the plateau is an elevated flat land. It is
a flat-topped table land standing
above the surrounding area
in India is one of the oldest plateaus.
The East African Plateau in Kenya,
Tanzania and Uganda and the
Western plateau of Australia
e Tibet plateau (Figure 5.1, p.31) is the
highest plateau in the world with a height of 4,000 to
6,000 metres above the mean sea level
Plateaus are very useful because they are rich in
mineral deposits. As a result, many of the mining areas
in the world are located in the plateau areas
African plateau is famous for gold and diamond mining. In India huge reserves of
iron, coal and manganese are found in the Chhotanagpur plateau
plateau areas, there may be several waterfalls as the river falls from a
great height. In India, the Hundru falls in the Chhotanagpur plateau on the river
Subarnarekha and the Jog falls in Karnataka. e lava plateaus are rich in black soil that are fertile and good for cultivation.
- plains are formed by rivers and their tributaries.
- Plains are large stretches of flat land. They are, generally, not more than 200m above msl
- The rivers flow down the slopes of mountains and erode them, deposit their load consisting of stones, sand and silt along with their courses and in their valleys and plains are formed.
- They are very fertile
- Construction of transport network is easy
- Thus, these plains are very thickly-populated regions of the world.
- largest plains made by the rivers are found in Asia and North America.
- For example - in Asia, these plains are formed by the Ganga and the Brahmaputra in India and the Yangtze in China
- Indo-Gangetic plains are the most densely populated regions of the country
7 OUR COUNTRY – INDIA
The peninsula is a piece of land that is surrounded by water on three sides
- north-south extent - 3,200 km
- east-west - 2,900 km
Large countries which stretch extensively from east to west do not have a single Standard Time
for the whole country. The USA and Canada have seven and six-time zones respectively
Seven countries that share land boundaries with India
Our island neighbours—Sri Lanka and the Maldives.
Sri Lanka is separated from India by the Palk Strait.
Alluvial deposits: These are very fine soils, brought by rivers and deposited in the river basins.
Tributary: A river or stream which contributes its water to the main river by discharging it into the main river from either side
Ganga and the Brahmaputra form the world's largest delta, the Sundarbans delta. The delta is triangular in shape. It is an area of land formed at the mouth of the river.
The Himalayan mountains are divided into three main parallel ranges.
- The northernmost is the Great Himalaya or Himadri. The world's highest peaks are located in this range.
- Middle Himalaya or Himachal lies to the south of Himadri. Many popular hill stations are situated here.
- The Shiwalik is the southernmost range.
Corals are skeletons of tiny marine animals called Polyps. When the living polyps die, their skeletons are left. Other polyps grow on top of the hard skeleton which grows higher and higher, thus forming the coral islands
The western coastal plains are very narrow. The eastern Coastal plains are much broader.
There are a number of east-flowing rivers. The rivers Mahanadi, Godavari, Krishna and Kaveri drain into the Bay of Bengal. These rivers have formed fertile deltas at their mouth. The Sunderban Delta is formed where the Ganga and Brahmaputra flow into the Bay of Bengal.
Two groups of islands also form part of India. Lakshadweep Islands are located in the Arabian Sea.
These are coral islands located off the coast of Kerala. and The Andaman and the Nicobar Islands
8 INDIA : CLIMATE, VEGETATION AND WILDLIFE
4 major seasons recognised in India
- Winter - December to February - Cold Weather Season
- Summer - March to May - Hot Weather Season
- Rainy - June to September - Southwest Monsoon Season
- Autumn - October and November - Season of Retreating Monsoon
- Hot and dry winds
- It blows during the day
- In summer
- When Temperature becomes very high
Rainy Season / Southwest Monsoon
- 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
Autumn Season / Retreating Monsoon
- Winds move back from the mainland to the Bay of Bengal.
- Tamil Nadu and Andhra Pradesh receive rainfall
The climate of a place is affected by its
- distance from the sea,
hot region - Jaisalmer and Bikaner in the desert of Rajasthan
cold region - Drass and Kargil in Jammu and Kashmir
Forests provide us with
- timber for furniture,
- fuel wood,
- medicinal plants and herbs,
Van Mahotsav Project Tiger and Project Elephant
Wildlife in India
- Asiatic lions - Gir forest in Gujarat
- Elephants and one-horned rhinoceroses 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
common birds are parrots, pigeons, mynah, geese, bulbul and ducks
Migratory Birds - Pintail Duck, Curlews, Flamingo, Osprey and Little Stint migrate
to our country in the winter season every year. Smallest migratory bird Little Stint Weighing
as low as 15 gram, from Arctic region travel over 8000 km to reach India.