Chapter 1 : Matter in our surroundings Melting Point -
Indication of the strength of the force of attraction between its particles As solid is heated, kinetic energy of particles increases and they start vibrating with greater speed
Latent Heat -
Amount of heat energy that is reqd to change 1 kg of a solid into liquid at atmospheric pressure at its melting point – Latent Heat of Fusion
SI unit of temp = Kelvin -
Melting Point of Ice 273.16 K
A change of state directly from solid to gas without changing into liquid state is called sublimation Applying pressure and reducing temperature can liquefy gases -
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Solid CO2 gets converted directly to gasesous state if pressure is reduced without coming into liquid state o Hence it is known as dry ice Atm – Pressure of air in atmosphere o 1 atm = 1.01 x 10^5 Pa
Evaporation -
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In case of liquids, a small fraction of particles at the surface, having higher kinetic energy, is able to break away from the forces of attraction of other particles and gets converted into vapour. Vapourization below boiling point – Evaporation Factors o Surface area o Increase in temp o Decrease in humidity – amount of water vapour rpesent in the air Air around us can’t hold more than a definite amount o Increase with wind speed Evaporation causes cooling o Particles of liquid absorb energy from surrounding to regain the energy lost during evaporation o Evaporation through absorbing heat required for latent head from surroundings o Wear cotton clothes during summer Cotton absorbs sweat and exposes it to atmosphere for evaporation Water droplets on the outside surface of a glass containing ice-cold water
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Vapour present in the air comes in contact of the glass, loses energy and gets converted to liquid state o Palm feels cold when we drop acetone 5 states of matter – S, L, G, Plasma, Bose-Einstein Condensate o Plasma Super energetic and super excited particles Particles in the form of ionized gases Neon sign bulb and fluorescent bulb (helium gas) Gas gets ionized when electrical energy goes through it Charging up creates a glow of special colour depending upon gas Sun and stars glow because of plasma o Bose-Einstein Condensate Satyandra Nath bose 2001, Corenell, Ketterle, Wiemann received Nobel Prize in Physics for achieving “Bose-Einstein condensation” BEC – cooling a gas of extremely low density to super low temperature
Chapter 14 : Natural Resources Outer crust of the earth is called the lithosphere Life-supporting zone of the earth where atmosphere, hydrosphere and lithosphere found is biosphere -
Living beings biotic components Air, water, soil abiotic component
14.1 The Breath of Life : Air Gases like Nitrogen, Oxygen, Co2 and water vapour – composition of air Eukaryotic and Prokaryotic cells need oxygen to break down glucose molecules and get energy for their activities - Results in production of Co2 Also combustion Despite the above two, percentage of Co2 is a mere fraction because CO2 is ‘fixed’ in two ways -
Green plants convert Co2 into glucose in the prescence of sunlight Many marine animals use carbonates dissolved in sea water to make their shells
14.1.1 Role of atmosphere in Climate Control Air – bad conductor of heat so atmosphere moderates earth’s temperature
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Moon’s surface termperature without atmosphere ranges from -190 C to 110C
14.1.2 The Movement of Air : Winds Atmosphere is heated from belw by the radiation that is reflected back by land or water bodies. On being heated, convection currents are set up in the air. Hotter hair rising up. Since land gets heated faster than water, the air over land would also be heated faster than the air over water bodies. So in coastal areas, as air over land rises, a region of low pressure is created and air over the sea moves into this area of low pressure. The movement of air from one region to other creates winds. At night, water cools down slower than the land. Hence air over land is cooler than water so air flows from land to sea as low pressure over water. A high pressure area is essentially a location where there is high force over a certain area. The pressure essentially is pushing all matter away from it, much the same way as if you were to drop a book, there would be a rush of air out from under it as it fell. All movements of air caused uneven heating of atmosphere in different regions as well as mountain ranges and rotation of the earth 14.1.3 Rain When water bodies are heated during the day, a large amount of water evaporates and goes into the air. Some amount of water vapour also get into the atmosphere because of various biological activities. This air also gets heated. The hot air rises up carrying the water vapour with it. As the air rises, it expands and cools. This cooling causes the water vapour in the air to condense in the form of tiny droplets. This condensation of water is facilitated if some particles could act as the ‘nucleus’ for these drops to form around. Normally dust and other suspended particles in the air perform this function. Once the water droplets are formed, they grow bigger by the ‘condensation’ of these water droplets. When the drops have grown big and heavy, they fall down in the form of rain. Sometimes, when the temperature of air is low enough, ppt may occur in the form of snow, sleet or hail.
14.1.4 Air Pollution When fuels are burnt, nitrogen and sulphur too are burnt and this produces different oxides of nitrogen and sulphur - they also dissolve in rain to give rise to acid rain. -
Acid Rain are caused by emissions of Sulphur Dioxide and Nitrogen which react with water molecules in the atmosphere to produce acids
Smog – suspended particles in cold air (when water also condenses out of air) Lichen is sensitive to levels of Sulphur Dioxide 14.2 Water : A wonder liquid
14.2.1 Water pollution Affects level of dissolved oxygen which adversely affect the aquatic organisms Change in temperature 14.3 Mineral Riches in the soil Quality of soil decided by the amount of humus (it causes soil to become more porous and allows water and air to penetrate deep underground) and also size of soil particles Earthworms help in making rich humus 14.4 Biogeochemical Cycles 14.4.1 The water cycle Some of the rain seeps into the soil and becomes part of underground reservoir of fresh water Underground water finds its way to the surface through springs
14.4.2 The nitrogen cycles Nitrogen gas makes up 78% of our atmosphere Nitrogen found in DNA/RNA or important compounds like alkaloids/Urea Other than a few forms of bacteria, life-forms are not able to convert the comparitively inert nitrogen molectules into nitrates and nitrites -
nitrogen fixing bacteria associated with few dicot plants found in the roots of legumes (pulses) in special structures called root nodules
During lightning, high temperatures and pressures created in air convert nitrogen to oxides of nitrogen -
These oxides then dissolve in water to give nitric and nitrous acides Acid Rain
Plants take up nitrates and nitrites to convert them into amino acides -
These are subsequently consumed by animlas
Once the animal dies, the various compounds of nitrogen convert it back intro nitrates and nitrites
14.4.3 The carbon-cycle Occurs in elemental form as Diamond and Graphite In the combined state, it is found as carbon dioxide in the atmosphere, as carbonate and hydrogen carbonate salts in various minerals
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Carbon present in proteins, carbohydrates, fats, nucleic acids and vitamins Endoskeletons (internal skeleton) and exoskeletons (like shells for turtles) are made of carbonate salts
Carbon incorporated into life-forms through basic process of photosynthesis which is performed with the help of sunlight by all life-forms that contain chlorophyll Utilization of Glucose releases CO2 Combustion also releases CO2 Greenhouse Effect -
Some gases prevent the escape of heat from earth An increase in percentage of such gases in the atmosphere would cause the avg temperatures to increase world wide which is called GH effect
14.4.4 The oxygen Cycle Oxygen – 21% of atmosphere
Oxygen from atmosphere mainly used in three processes -
Combustion Respiration Formation of oxides of nitrogen
Oxygen returned to atmosphere only in photosynthesis Some forms of life ie bateria are poisoned by elemental oxygen(even process of nitrogen fixing does not take place in prescence of oxygen)
14.5 Ozone Layer O3 – it’s poisonous and found at upper reaches of atmosphere It performs the vital function of absorbing harmful IR radiations from sun But CFCs (Choloro fluoro carbons) react with Ozone molecules causing its depletion A hole in Ozone layer has been found near Antarctica
Chapter 15 : Improvement in Food Resources 15.1 Improvement in Crop yields Wheat, rice, maize, millets, sorghum provide carbohydrates Pulses like gram (chana), pea (matar), black gram (urad), green gram (moong), pigeon pea (arhar), lentil (masoor) Oil seeds – soyabean, groundnut, sesame, castor, mustard, linseed Fodder crops like berseem, oats, sudan grass Photoperiods – different climatic conditions, temperatures -
Related to duration of sunlight
Seasons -
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Kharif – June to Oct (rainy season) o Paddy, soyabean, Pigeon pea (arhar), Maize, Cotton, Green Gram (moong), Black Gram (urad) Rabi o November to April o Wheat, Gram, mustard, Linseed
Improving yield -
Crop Variety Improvement (quality/choice of seeds for planting) Crop Production Management (Nurturing of Plants) Crop protection Management
15.1.1 Crop Variety Improvement Hybridisation – genetically crossing dissimilar plants -
Intervarietal (between different varieties) Interspecific (between two different species of same genus) Intergeneric (Between different genus)
Introducing a gene that woud provide a certain characteristic – GM crops Some of the factors for which variety improvement is done -
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Higher yield – to increase the productivty of the crop per acre Improved quality – Baking quality in wheat, Protein quality in pulses, Oil quality in oilseeds Biotic and abiotic resistance o Biotic (diseases, insects, nematodes) o Abiotic (drought, salinity, water logging) Change in maturity duration o From sowing to harvesting Desired agronomic characteristics o Tallness and profuse branching in fodder crops o Dwarfness desired in cerals
15.1.2 Crop Production Management
Farmer’s purchasing capacity for inputs decides cropping system and production practices
15.1.2 (i) Nutrition Management
There are 16 nutrients which are essential for plants Air – Oxygen, Carbon and Hydrogen and soil provides other 13 nutrients Amongst 13, 6 required in large quantity – known as macro nutrients -
N, P, K, Ca, Mg, S Micronutrients o Fe, Mn, B, Zn, Cu, Mb, Cl
Manure -
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Decomposition of animal exreta and plant waste Manure helps in imporving soil structure o Increases water holding capacity o In clayey soils, it helps in drainage and in avoiding water logging Based on the kind of biological material used, manure can be classified as o Compost and vermi-compost Livestock excreta in puts known as composting When earthworms used to quicken the decomposition – it is known as vermi composting o Green manure Prior to sowning, some plants like sun hemp or guar are grown and then mulched by ploughing them into the soil These green plants thus turn into green manure which helps in enriching the soil in Nitrogen and Phosphorous
Fertilizers -
Supply N, P, K Destroys soil fertility as micro-organisms are harmed – long term Water polluted as irrigation water washes awayfertilizers Oraganic Farming o Manure, minimal use of chemicals o Bio-agents, biofertilizers like neem leaves, turmeric, blue green algae
15.1.2 (ii) Irrigation
Droughts – Light soils have less water retention capacity
Irrigation sources -
Wells – Dug wells (water from water bearing strata) and tubewells (water from deeper strata) Canals – receive water from reservoirs and is subranched into further canals River Lift systems – Water is directly drawn from rivers in areas close to rivers Ranks – small storage reservoirs
Rainwater harvesting, building small check-damsn to increase ground water levels (also reduce soil erosion) 15.1.2 (iii) Cropping Pattern Mixed Cropping -
Two or more crops on the same piece of land o Wheat + Gram, Wheat + Mustard, Groundnut + Sunflower Reduces risk and gives some insurance against failure of crops
Inter cropping – growing two or more crops simultaneously in a definite pattern -
A few rows of one crop alternate with a few ros of the 2nd crop Soybean + maize, finger millet (bajra) + cowpea (lobia) Ensures maximum utilization of nutrients supplied Prevents pests and diseases from spreading to all the plants belonging to one crop in a field
Crop rotation -
Growing of different crops on a piece of land in a pre-planned succession is known as crop rotation
15.1.3 Crop Protection management
Protection from weeds which compete for food, space and light. Xanthium (gokhroo), Parthenium (gajar ghas) Insects -
Cut the root, stem and leaf Suck the cell sap from various parts of the plant Bore into the stem and fruits
Storage of grains -
Biotic Abiotic (inappropriate moisture and temperature0
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Degradation in Quality, Loss in Weight, Poor Germinability, Discolouration of Produce all leading to poor marketability
15.1 Animal Husbandry Scientific Mgmt of livestock -
Feeding Breeding Disease control
Stress on humane treatment of animals – limitation in livestock farming 15.2.1 Cattle Farming 2 purposes -
Milk Draught labour o Tilling o Irrigation o Carting
Indian cattle belong to two different species -
Cows – Bos indicus Buffaloes – Bos Bubalis
Milk-producing females known as milch animals while the ones used for farm labour known as draught animals Milk period depends on lactation period (duration of milk production after birth of calf) Milk Production can be increased by increasing the lactation period -
Exotic foreign breeds are selected for lactation periods (Jersey, Brown Swiss) while local breeds (Red Sindhi, Sahiwal) show excellent resistance to diseases The two can be cross-bred to get desired qualities
The floor of cattle shed needs to be sloping so as to stay dry and to facilitate cleaning Food requirements -
Maintenance type – food required to support the animal to live a healthy life Milk producing requirement – food requried during lactation period
Animal feed includes -
Roughage – Fiber
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Concentrates – low in fibre and contain proteins and other nutrients
Both internal and external parasites can affect cattle 15.2.2 Poultry Farming
Domestic fowl for egg production and meat Cross breeding programmes between Indian (Aseel) and foreign (leghorn) for new desirable traits like -
Number and quality of chicks Dwarf broiler parent for commercial chick production o Broilers are domesticated fowls raised specifically for meat production Tolerance to high temperature Low maintenance standards Size of egg-laying bird with ability to utilize diets from agricultural by products
Food requirement for broilers is protein rich with adequate fats with high level of Vitamins A and K 15.2.3 Fish Production
Includes finned true fish as well as shellfish like prawns and molluscs 2 ways of obtaining fish -
Capture fishing – from natural resources Culture fishery – fish farming
Both marine and freshwater Marine Fisheries -
7500 km of coastline and waters beyond it Popular fish – Pomphret, Mackerel, Tuna, Sardines, Bombay Duck (not a duck but a lizardfish) Yields are increased by locating large schools of fish in open sea using satellites and echosounders Finned fish of high economic value – mullets, bhetki, pearl spots Shellfish like prawns Oyesters cultivated for pearls As fish stocks get depleted, demand can be met by fish farming known culture fishery, a practice called mariculture
Inland fisheries
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Rivers, canals, ponds and brackish water resources (where sea water and fresh water mix together such as estuaries and lagoons) Capture fishing also done but yield is not high Most fish production from these resources is through aquaculture Fish culture is sometimes done with rice crop in the paddy field Intensive fish farming – composite fish culture systems - combination of 5-6 fish species used in a single fish pond (generally non-competitors for food) o Catlas, Rohus, Mrigals, Grass carps feed on different layers o One problem, many fish breed in monsoon o Breeding done through hormonal stimulation
15.2.4 Bee-keeping - bee farms – apiaries o to increase honey yield, depends on pasturage which is flowers available to the bees for nectar and pollen collection - Apis Cerana indica – Indian bee - Italian bee variety high honey collecting capacity and sting somehwat less and stay in beehive for longer periods o A. mellifera - Value of honey depends on the pasturage or the flowers available to bees for nectar and pollen collection
