Geography Class 06 NCERT

1. Celestial bodies - what are they?
1. Celestial bodies made up of gases with own light and heat are stars.
2. Celestial bodies lit by light of other stars are planets. We get out light and heat from the sun.
2. Inner planets made up of rocks - till Mars /asteroid belt.
1. Jupiter to Neptune - huge planet s made up of gases and liquids. Jupiter has 69 moons (highest)
3. Sun - provides pulling force that binds solar system. Sun- Earth distance 150 million km. International Astronomical Union - Pluto, Ceres, UB313 - classifi ed them as dwarf planets.
4. Earth
1. shape of geoid. Moon - diameter 1/4 of earth. 384k km away, moon orbit time - 27 days, spin time also same => only one side of the moon is visible to us (far side of the moon).
2. USA Russ ia Japan India China all have had probe landing on moon. A
3. steroid belt - part of a planet that exploded.
5. Galaxy - huge system of billions of stars, clouds of dust and gases.
6. Latitudes - equator represents zero latitude.
1. Equator to poles measure 1/4 of 360=90 degrees.
2. Tropic of Cancer 23 1/2 degrees.
3. Arctic circle 66 1/2 degrees.
4. Size of parallel decreases as we approach the poles.
7. Torrid zone (Tropics)
1. Mid -day sun exactly overhead at least once a year on all latitudes b/w Tropic of Cancer and Capricorn.
2. Mid-day sun never shines overhead on any latitude beyond that.
3. Angle of sun's ray goes on decreasing towards the poles.
4. Tropic of Cancer/Capricorn and Arctic Circle/Antarctic Circle have temperate climate - Temperate Zone. From there to poles - Frigid Zone
8. Longitudes - Lines of reference called meridians of longitudes.
1. Distance b/w them decreases steadily towards poles, at poles it is zero.
2. All longitudes of equal length.
3. Starts at Greenwich (why - British Royal Observatory) - prime meridian.
4. 1 degree = 4 mins. IST - 82 1/2 degrees.
5. Russia has 11 time zones, earth has 24 (15 degrees = 1 time zone).
6. All longitudes have mid-day at the same time.
9. Movement of earth
1. Rotation - movement of earth on its axis. Axis of earth, an im aginary line, makes angle of 66 1/2 with its orbital plane (plane formed by orbit). The circle that divides day from night (vertically) is called circle of illumination. If no rotation, one side always hot one side always freezing cold. Takes 24 hours.
2. Revolution - around the sun in a fixed path. Takes 365 1/4 days. Earth goes around in an elliptical orbit.
10. Solstice/equinox
1. Winter solstice -22nd December - direct rays of the sun on Tropic of Capricorn. Christmas in Australia in summe season.
2. Summer solstice 21 June - north hemisphere tilted towards sun => rays directly on Tropic of Cancer. Summer in north hemisphere. Longest day and shortest night. Everything reverse in south hemisphere.
3. Equinox - 21 March and 23 Sep - direct rays on Equator.
11. Components of map - distance, direction and symbol.
1. Scale is ratio b/w actual distance and distance on map.
2. Four major directions - cardinal points
12. Components of environment -
1. lithosphere (land),
2. atmosphere (gaseous layer),
3. hydrosphere (water).
4. Biosphere - narrow zone where all together contains all forms of life.
5. Lithosphere - continents and continental basins.
6. Isthmus - narrow strip of land joining two land masses
13. Hydrosphere - 97.2% oceans, 2.8% water - 0.03% fresh water, 2.77% ice sheets and ground water.
1. Pacific is largest 1/3 of earth, almost circular.
2. Atlantic - indented coastline, ideal for natural harbours and ports - busiest ocean.
14. Atmosphere - extends up to 1600 km.
1. Divided into 5 layers based on composition, temperature, etc.
2. Atmosphere - 78% nitrogen, 21% oxygen and 1% others (Argon is 0.93%, CO2 is 0.03%, balance). Carbon dioxide - important for it absorbs heat radiated by Earth => planet warm.
3. Air Density maximum at sea level and decreases as we go up. Air moves from high pressure to low pressure, moving air is known as wind.
15. Biosphere - organisms in biosphere divided into
1. plant
2. animal kingdom.
16. Landforms - result of two processes - internal and external.
1. Internal - leads to upliftment and sinking of earth's surface.
2. External - continuous wearing down and rebuilding of land surface. Erosion (wearing away of surface), deposition (rebuilt process). Both happen by way of running water, ice and wind.
17. Mountains - natural elevation of earth surface. Glacier - frozen river of ice in mountains. Mountains arranged in a line are a range.
1. Three types of mountains -
1. Block - created when large areas are broken and displaced vertically. Uplifted blocks are called horsts and lowered blocks are graben. E.g. Rhine Valley, Vosges.
2. volcanic - formed due to volcanic activity. E.g. Kilimanjaro, Fujiyama.
3. Fold - formed by folding of earth's crust. E.g. Aravali (old), Himalayas and Alps (new), Rockies, Andes.
1. Bachendri Pal - first Indian woman to climb Everest 1984
2. Plateaus - rich in mineral deposits. African plateau - gold and diamond. Chhotanagpur - iron, coal, manganese. Gondwana rocks have coal formation. Archean system covers 2/3 of Indian peninsula.
3. Plains - not more than 200m above sea level. Formed by rivers and their tributaries, flowing down the slopes of mountains and eroding them. Deposit the load (sand, silt, stones) along their courses. These deposits form plains.
18. India boundary
1. 3.28m sq km.
Kashmir to Kanyakumari 3200 km.
2. Arunachal to Kutch 2900 km.
3. Latitudes - 8•4'N to 37•6'N. longitudes - 68•7'E to 97� 'E.
4. Indian standard time - 82•30 near Allahabad.
5. Longest land border with Bangladesh,
6. land border with 7 nations including
1. Afghanistan (100 km in Wakhan Corridor)
7. Himalayan mountains - great Himalaya or Himadri, middle Himalaya or Himachal, Shivalik.
8. Plains - formed by alluvial deposits of Indus, Ganga and Brahmaputra (and their tributaries).
9. Peninsular plateau - Aravali on north west, Vindhayas and Satpuras in north (Narmada and Tapi flowing through - west flowing).
10. Western Ghats/ Sahyadri in west, Eastern Ghats provide east boundary.
11. Coastal plains - west is narrow, east are much broader.
12. East flowing river - Mahanadi, Godavari, Krishna and Kaveri.
13. Corals are skeletons of polyps - other polyps grow on top of hard skeleton thus forming coral islands.
19. Major recognised seasons in India
1. India climate - monsoon type.
2. cold, hot, southwest monsoon and retreating monsoon.
3. Climate is average weather conditions measured over many years.
4. Climate affected by - location, altitude, distance from the sea and relief.
20. Vegetation of India - 5 types.
1. tropical rain forest - heavy rainfall areas. So dense that sunlight doesn't reach ground. Trees shed leaves at different times of year. Therefore always green and called evergreen forests. E.g. Mahogany, ebony and rosewood. In India - A&NI, parts of NE states and narrow strip of western slope of Western ghats.
2. Tropical deciduous forests - monsoon forests. Less dense and shed leaves during particular time of year. E.g. Sal, peepul, neem and sheesham. In India - MP, UP, Bihar, Jharkhand, Chhattisgarh, Odisha and parts of Maha.
3. Thorny bushes - in dry areas of country. Leaves in form is spines to reduce loss of water. E.g. Cactus, khair, babool, keekar. In India - Rajasthan, Punjab, Haryana, Eastern slopes of western ghats and Gujarat.
4. Mountain vegetation - height between 1500-2500m trees are conical in shape, called coniferous trees. E.g. Chir, pine and deodar.
5. Mangrove forest - can survive in saline water. Mainly in Sunderbans (largest delta in world) and A&NI. E.g. Sundari (eponymous). Migratory birds - pelican, Siberian crane, stork, flamingo, pintail duck and curlew migrate in winter season.
21. Gyrocompass is similar to a gyroscope. It is a non-magnetic compass that finds true north by using an (electrically powered) fast-spinning wheel and friction forces in order to exploit the rotation of the Earth.