Modern Concept Science and Technology NOVA Science Book 9 347Effect of lack of zinc on the human bodyi. Slow healing of woundsii. Diarrhoeaiii. Loss of hairiv. Decline in sense of smellIronIron is an important metal for us. It is present in our red blood cells. It absorbs oxygen from the lungs. It gives a red appearance to the red blood cells.Source of ironIron can be obtained from milk, meat, and fish. It is also present in broccoli and cereals.milk meat vegetablesThe function of iron in the human bodyi. It helps in respiration.ii. It reduces tiredness.iii. It improves the immunity system.iv. It helps in the formation of DNA.Effect of lack of iron in the bodyi. Low RBC countii. Anaemiaiii. Tiredness and weaknessSodiumSodium ions are very important for the functioning of the nervous system. They help in the sodium-potassium pump.Source of sodiumSodium is found in table salt, baking soda, meat, fish, eggs, milk, beet, etc.
348 NOVA Science Book 9 Modern Concept Science and Technologytable salt baking soda olivesThe function of sodium in the bodyi. It helps in muscle contraction.ii. It helps to balance the amount of water in the body.iii. It helps to maintain blood pressure and blood volume.iv. It helps in the transfer of nerve impulses.Effect of lack of sodium in the bodyi. Swelling of cellsii. Loss of reflexive movementsiii. Muscle twitching and seizureiv. Confusion and sluggishnessPotassiumPotassium is a mineral that helps to regulate fluid in the body. It is found insidecells and is necessary for good health.Source of potassiumMany foods contain potassium, including all meats, some types of fish, manyfruits, vegetables, legumes, etc.legumes meat fruitsFunction of potassiumi. It helps in the normal functioning of the cells.ii. It helps to balance the volume of liquid inside the cell.iii. It helps to build protein and muscle.iv. It helps in the normal growth of the body.
Modern Concept Science and Technology NOVA Science Book 9 349Effect of lack of potassium on the bodyi. Nausea and vomitingii. Extremely low blood pressure and faintingiii. Bloating, constipation, and abdominal crampiv. Weakness, fatigue, and muscle crampMemory NoteNeurons and muscle cells are electrically excitable cells. Ions (Na+, K+) in our bodies cause an electrical impulse. Neurons send messages electrochemically.MercuryThe poisonous effect of mercury in the human body is called hydrargyria.Sources:Contaminated fish, tube light, thermometer, etc. Effects:One drop of mercury may block blood vessels and cause the death of the victim. The compounds of mercury damage the brain. Similarly, they weaken the ability to speak, hear and see things.Fact and ReasonMercury is dangerous to humans, why?Mercury is a metal known to be highly toxic, especially due to its ability to damage the central nervous system. So, mercury is dangerous to humans.LeadLead poisoning is an environmental hazard that is capable of causing mental retardation, behavioural disturbance, and brain damage.Sources:Some cosmetic lip products, colouring pigments, lead-based paints, contaminated soil, aeroplane fuel, some toys, and some metal jewellery.Effects:i. Symptoms like headache, abdominal pain, change in behaviour, lack of brain development, etc. occur in children.
350 NOVA Science Book 9 Modern Concept Science and Technologyii. Blood cannot combine with oxygen due to the presence of lead which causes anaemia.iii. Lead accumulates in bones which affects the formation of blood cells in the bone marrow.Memory NoteHumans can be exposed to lead while eating food and drinking water containing lead. The exposure may happen from dishes or glasses that contain lead. It may also be due to inhaling lead dust from lead-based paints or lead-contaminated soil.Fact and ReasonLead poisoning causes anaemia. Give reason.Acute poisoning of lead can damage red blood cells in the bloodstream. It limits their ability to carry oxygen to the organs and tissues that need it, thus causing anaemia.1. Metals: Metals are those electropositive elements that are good conductors of heat and electricity. 2. Malleability: The property of a metal due to which it can be beaten into thin sheets is called malleability. 3. Ductility: The property of a metal due to which it can be drawn into a long wire is called ductility. 4. Non-metals: Non-metals are those electronegative elements that are bad conductors of heat and electricity. 5. Lustre: A brilliant metallic soft glow is called lustre. Terms and terminologiesEXERCISESTEP 1 Multiple Choice Questions1. Choose the best answer from the given alternatives. a. What are the electropositive elements with good conductivity called?i. Metals ii. Non-metals iii. Conductors iv. Insulators
Modern Concept Science and Technology NOVA Science Book 9 351b. Which properties describe the metal? i. Ductility, malleability, conductivity ii. Poor conductivity, soft, dull iii. Produce water, form bloodiv. Damage brain, solid substances c. Study the given facts and answer the following questions.An average adult human body contains 3 to 4 grams of iron. QuestionsWhy is it necessary for our body?i. Muscle contraction, balance water ii. Respiration, immunity systemiii. Build muscle, protein synthesis iv. Enzyme synthesis, smelld. Identify sodium and potassium in the given concept map. Increases blood pressure A Metal B Decreases blood pressurei. A is a mineral. B is a vitamin. ii. A is mercury. B is lead. iii. A is potassium. B is sodium. iv. A is sodium. B is potassium. e. Which of the following is a set of useful metals for our body?i. Sodium, zinc, aluminium ii. Sodium, potassium, iron iii. Iron, copper, mercury iv. Lead, zinc, uranium STEP 2 Very Short Answer Type Questions2. Define the following terms. (a) Metals (b) Malleability (c) Ductility (d) Conductor (e) Insulator (f) Non-metals 3. Give an example of a metal that has a high melting point and boiling point.4. Which metal exists in a liquid state at normal temperature and pressure? 5. Which non-metal has lustre? 6. Which metal is neither malleable nor ductile?
352 NOVA Science Book 9 Modern Concept Science and Technology7. Which non-metal conducts electricity? 8. Give two examples of highly toxic metals. 9. Write the names of the metals A, B and C. Its presence causes anaemia. Its absence causes anaemia.It is solid. A BIt is liquid. C D STEP 3 Short Answer Type Questions10. Write any two differences between: (a) Metals and Non-metals (b) Role of iron and Role of zinc in the human body (c) Effect of sodium and Effect of lead in the human body 11. Give suitable reason.(a) We should consume sodium-rich food frequently. (b) Zinc is necessary for children. (c) A mercury thermometer should not be given to children. (d) Lead-based paints should not be used. (e) Gold is used to make ornaments.12. Write two chemical properties of metals. 13. Write any four physical properties of metals. 14. Write any four physical properties of non-metals.15. What happens to us due to a lack of iron ions in the body?16. Study the given feature and answer the following questions.Elements A and B are metals. The presence of A in the blood improves the health of the nervous system. The presence of B in the blood harms the nervous system. Questions Which metal between A and B is sodium and which one is lead? What are the other two effects of B on human health? 17. Is the given element metal or non-metal? Write the other two properties of this element.
Modern Concept Science and Technology NOVA Science Book 9 353Element Malleability Ductility Conductivity A Present Present High STEP 4 Long Answer Type Questions18. What is the importance of metal in the human body? 19. Write any two negative impacts each of mercury and lead on the human body. 20. Study the given conversation and answer the following questions. Rita: Iron is beneficial for our health. Should I chew it or boil it?Gita: We neither chew it nor boil it. We get iron from the foods we eat.QuestionsWhat are the sources of iron for our body? Write its benefits in our body. 21. Study the hypothetical story given below and answer the following questions.Ram took his kid to the hospital. The kid had intense stomach pain, respiratory problems, vomiting, and kidney problems. The doctor asked if they were eating anything unusual. They were eating mercury-rich fish from the polluted river. QuestionsWhich disease is the child suffering from? What are the causes of this disease? Mention its symptoms. MCQ a b c d e Answer i i ii iv ii Metals are essential for our good health. They help us in multiple ways. Find out the metal that helps us in breathing. Discuss its other uses as well. PROJECT WORK
354 NOVA Science Book 9 Modern Concept Science and TechnologyDr. Surendra Shrestha is a scientist in computer science. He also helped in research on the comparison using simulation of carbon allotropes-based nanostrip antennas, graphene light, and the International Workshop on Nanophysics and Nanotechnology. He is an elected member of the Nepal Engineering Council, Nepal. Dr. Surendra ShresthaInspiring Nepalese ResearcherStudy the given features of two substances that are made of pure carbon atoms. Allotrope A Allotrope BIt is soft, black, opaque, and lustrous. It is hard, transparent, and colourless. It is a good conductor of heat and electricity.It is a good conductor of heat but bad a conductor of electricity. Questionsi. Which one is a graphite between A and B? ii. Which one is a diamond between A and B? iii. Which one of them is used to make a pencil, and why? iv. What are the uses of allotrope B?WARM UP ACTIVITYIntroductionCarbon is one of the most important and unique non-metallic elements. The word carbon has been derived from the Latin word ‘carbo’, which means shoot or charcoal. Carbon is widely distributed on the earth in free as well as in the combined state. In a free state, it is present in diamond, graphite, charcoal, coal, etc. whereas, in a combined state, it is present in carbon monoxide, carbon dioxide, carbonates, carbohydrates, proteins, fats, nucleic acids, petroleum, natural gas, etc. The bodies of living beings contain carbon and its compounds in abundance. When we burn these carbon-containing compounds, we get black shoots, smoke, charcoal, etc.CARBON AND ITS COMPOUNDSUNITESTIMATED TEACHING PERIODS18TH PR4 2
Modern Concept Science and Technology NOVA Science Book 9 355Memory NoteNearly 20% of our body is carbon.ActivityObjective: To prove sugar contains carbon.Materials required: Sugar, hard glass test tube, and source of heat (Bunsen burner)Procedure: Keep some sugar in the hard glass test tube and heat it with the help of a Bunsen burner.Observation1. Initially at about 186°C sugar melts and gives yellowish syrup.2. On further heating, it turns into a brownish mass with a good smell which is called caramel.3. At the final stage, the mass is converted into black matter called charcoal, i.e. carbon.Conclusion: The above activity shows that sugar contains carbon.Structure of Carbon Atom Symbol = CAtomic number = 6Atomic mass = 12Electronic configurationShell K LNo. of electrons 2 4Position in periodic table: Period – 2, Group – IVASource of carbonCarbon occurs in different forms in nature. The major sources of carbon are asfollows:i. All organic compounds which are obtained from living organisms contain carbon.ii. Rocks containing carbonate, minerals, petrol, natural gases contain carbon as one of the constituents.iii. Carbon monoxide, carbon dioxide, etc. contain carbon as one of theelements.CCarbon atom
356 NOVA Science Book 9 Modern Concept Science and TechnologyThe various forms (sources) of carbon in the form of an element, compound, and gas are given below:Carbon as an elementCarbon as an organic compoundCarbon as an inorganic compoundCarbon as a gasCoal Carbohydrate Carbonate Carbon dioxideCoke Protein Bicarbonates Carbon monoxideCharcoal Ghee and oilCarbides such asCaC2Methane, ethaneGraphene Petrol and diesel Rocks LPGDiamond Silk, paper, soap Minerals Water gasMemory NoteCarbon helps us to determine the age of the object.Nature of carbonCarbon has four electrons in its valence shell.The carbon atom has a small atomic size and more electronegativity. So, it attracts electrons strongly towards its nucleus. Therefore, loss or gain of four electrons by carbon atom is not possible. As a result, carbon shares its valence electrons with other atoms to attain a stable electronic configuration. Hence, it forms four covalent bonds as shown in the given structure.ActivityMake a model of the atomic structure of the carbon atom.a. CatenationCarbon shows the mutual sharing of its four electrons with other carbon atoms or atoms of other elements to form a large number of covalent compounds. Carbon is one of the unique elements which can join with each other to form a long carbon chain which is called the catenation property of (Methane)Or, 6p+6n01p+0n01p+0n01p+0n01p+0n0HHH C HMolecular structure of methane
Modern Concept Science and Technology NOVA Science Book 9 357carbon. Due to this property of carbon, a large number of carbon compounds are found in nature. The number of carbon compounds is more than the number of compounds formed from other elements. This is the reason why we have a separate branch of chemistry to study carbon compounds or hydrocarbons which is called organic chemistry.H HH H H H H HH H H H H HC C C C C CLong chain of carbonsFact and ReasonWhy do carbons make a covalent bond?There are four valence electrons in carbon. Due to its small atomic size, it can neither lose four electrons nor gain four electrons to be stable. So, it forms a covalent bond by sharing electrons.b. Allotropy of CarbonThe different forms of an element with different physical properties are called allotropes.Carbon occurs in different forms with different physical properties which are called allotropes. The characteristic by which carbonexists in various forms in nature is called allotropy. Diamond is one of the hardest allotropes which is transparent, brilliant, and precious whereas graphite is another soft, slippery, black, and greasy allotrope of carbon.The diamond is hard, compressed carbon. Each of its valence electron is bonded. It does not have free electron and cannot pass electricity. The graphite is soft, black carbon. It has a free valence electron and can pass electricity.Memory NoteLampblack is the form of carbon that can be obtained from the flame of the kerosene lamp. It is used to make black ink. Similarly, it is also used as collyrium (gajal).Coke is a fuel with few impurities and high carbon content. Usually, it is made from coal. It is used as fuel.Allotropic forms of carbon
358 NOVA Science Book 9 Modern Concept Science and TechnologyActivityCollect samples of different allotropes of carbon.Carbon is a non-metallic element that occurs in different physical forms. Among them, some exist in crystalline forms like diamond and graphite and some in amorphous forms like coal, charcoal, coke, etc.Crystalline formsDiamondGraphite black leadFullereneAmorphous formsCoalCokeCharcoalLampblackAllotropes of CarbonPhysical properties of carboni. It is present in amorphous and crystalline solids.ii. It is a non-metallic element.iii. It shows different allotropes.iv. It does not dissolve in water.v. Carbon is black.vi. At high temperatures carbon changes from solid to gas.Chemical properties of carboni. Combustion in airCarbon burns in excess air to give carbon dioxide gas. C + O2 CO2If the amount of oxygen is insufficient, it forms carbon monoxide.2C + O2 2COii. Reducing nature of carbonCarbon is a good reducing agent. It reduces less reactive metallic oxides into free metal.PbO + C ∆ Pb + CO ZnO + C ∆ Zn + CO
Modern Concept Science and Technology NOVA Science Book 9 359Fact and ReasonCarbon is called a reducing agent. Why?Carbon is called a reducing agent because it reduces less reactive metal oxide into free metal.iii. Reaction with steamWhen carbon is strongly heated with steam at about 900–1000°C, a mixture of carbon monoxide and hydrogen gas is obtained which is called water gas.C + H2O 900 – 1000°C CO + H2 (water gas)Memory NoteThe mixture of carbon monoxide and hydrogen (CO + H2) is called water gas. It is used in industries as a source of heat.iv. Reaction with calcium oxide (CaO)When carbon reacts with calcium oxide or lime, it gives calcium carbide and carbon monoxide.3C + CaO CaC2 + CO (Calcium carbide)v. Reaction with metalCarbon reacts with calcium and forms calcium carbide. 2C + Ca CaC2 (Calcium carbide)Organic and inorganic compoundsOrganic compoundsIn ancient times, scientists believed that organic compounds were produced within the body of living beings by the natural processes. They also believed that the formation of organic compounds took place under the influence of vital force and they could not be prepared in the laboratory. But in 1828 AD, German chemist Friedrich Wohler synthesised urea in the laboratory by heating ammonium cyanate.NH4CNO ∆ NH2 – CO – NH2(Ammonium cyanate) (Urea)Here, ammonium cyanate is an inorganic compound whereas urea is an organic compound. This experiment displaced the vital force theory of organic
360 NOVA Science Book 9 Modern Concept Science and Technologycompounds. Thereafter many organic compounds were synthesised artificially in the laboratory. The compounds formed by the reaction of carbon with elements like hydrogen, oxygen, nitrogen, etc., are called organic compounds. Examples: methane, ethane, propane, butane, alcohol, ether, glycerol, etc. The branch of chemistry in which we study organic compounds is called organic chemistry.Properties of organic compoundsi. They have a covalent bond.ii. They have a low melting point and low boiling point.iii. They do not ionise in water.iv. They burn easily.Inorganic compoundThe compounds which are derived from minerals are called inorganic compounds.They contain other elements except for hydrocarbon. For example, water, sodium chloride, calcium carbonate, hydrochloric acid, etc. The branch of chemistry in which we study inorganic compounds is called inorganic chemistry.Memory NoteThere are certain compounds like CO2 and CO that contain carbon but are traditionally called inorganic compounds. Compounds like CaCO3, Na2CO3 etc. also contain carbon atoms but they have an electrovalent bond and they do not have hydrogen. So, these compounds are called inorganic compounds.Fact and ReasonWhy does oil boil earlier than water?Oil boils earlier than water because oil is an organic compound with a low boiling point whereas water is an inorganic compound with a high boiling point.Properties of inorganic compoundsi. They have an electrovalent bond.ii. They have high melting and boiling points.iii. They ionise in water and can pass electricity.iv. They do not burn.Memory NoteOrganic compounds are usually soluble in organic solvents, such as ether, alcohol, benzene, etc. and insoluble in water. Whereas inorganic compounds are soluble in water but insoluble in organic solvents. Some organic compounds that can make hydrogen bonds with water, dissolve in water. Examples are glucose, sugar, alcohol, etc.
Modern Concept Science and Technology NOVA Science Book 9 361Differences between organic and inorganic compoundsSN Organic compound SN Inorganic compound1 Carbon-containing compounds are called organic compounds. 1Compounds of elements other than hydrocarbon are called inorganic compounds.2They have a covalent bond. So, they are called covalent compounds.2They have an electrovalent bond. So, they are called electrovalent compounds.3 They have low melting and boiling points. 3 They have high melting and boiling points.4 They are soluble in organic solvents like ether, benzene, etc. 4 They are soluble in water.5 They burn easily. 5 They do not burn easily.6Organic compounds are generally covalent compounds and do not ionise when they are dissolved in water.6Many inorganic compounds are electrovalent and usually ionise in water.Uses of organic compounds in our daily lifei. Organic compounds are used for manufacturing different kinds of organic materials such as dyes, detergents, soap, fuel, etc.ii. They are used to make plastic, rubber, pesticides, and fertilizer.iii. They are used to make cosmetic items and pharmaceutical goods.iv. Certain organic compounds are used to treat diseases.v. Organic compounds such as oil, sugar, ghee, etc. are food materials.vi. Some organic compounds are used as laboratory reagents.vii Fossil fuels, firewood, and gobar (animal dung) gas are organic compounds.viii. Clothes are made up of fibres which are organic compounds.1. Catenation: The property of carbon which allows carbon to join with each other to form a long carbon chain is called the catenation property of carbon. 2. Allotropes: The different forms of an element with different physical properties are called allotropes. 3. Allotropy: The characteristic by which carbon exists in various forms in nature is called allotropy. Terms and terminologies
362 NOVA Science Book 9 Modern Concept Science and Technology4. Water-gas: A mixture of carbon monoxide and hydrogen gas is called water gas. 5. Organic compounds: The compounds formed by the covalent bonding of carbon with elements like hydrogen are called organic compounds. 6. Organic chemistry: The branch of chemistry in which we study organic compounds is called organic chemistry. 7. Inorganic compounds: The compounds which are derived from minerals are called inorganic compounds. 8. Inorganic chemistry: The branch of chemistry in which we study inorganic compounds is called inorganic chemistry. Terms and terminologiesEXERCISESTEP 1 Multiple Choice Questions1. Choose the best answer from the given alternatives. a. What is the property of carbon that allows it to form a very long chain of multiple carbon atoms? i. Catenation ii. Allotropy iii. Ionization iv. Combustion b. Fill in the blanks. The compounds made of hydrogen and carbons are called …… i. Electrovalent compound ii. Neutral compound iii. Organic compound iv. Inorganic compounds c. Identify the given allotrope of carbon. i. Coal ii. Graphite iii. Diamond iv. Charcoal d. Compound A has a low melting point. Compound B has a high melting point. Compound A has a covalent bond but compound B has an electrovalent bond. What is true for A and B? i. A is an organic compound. B is an inorganic compound.ii. A is an inorganic compound. B is an organic compound. iii. A is a solid compound. B is a gaseous compound. iv. A is a harmful compound. B is a useful compound.
Modern Concept Science and Technology NOVA Science Book 9 363e. Identify the true statement. i. Carbon is a metallic element that exists as various allotropes. ii. Carbon reduces highly reactive metal oxides into free metals. iii. Inorganic compounds are studied in organic chemistry. iv. Diamond is transparent, but graphite is black and opaque. STEP 2 Very Short Answer Type Questions2. Define the following terms.(a) Carbon (b) Catenation (c) Allotropes (d) Allotropy (e) Water-gas (f) Organic compound (g) Inorganic compounds (h) Diamond (i) Graphite 3. What are the sources of carbon? What is the valency of carbon?4. Name two crystalline allotropes of carbon. 5. What is the reducing property of carbon? 6. Give two examples of inorganic compounds.7. Write the conclusion of the given activity, shown in the diagram. 8. Study the given conversation and answer the following questions. Rita: I see that oil does not dissolve in water.Sita: Yeah! Petrol also does not dissolve in water. Questions:Why don’t oil and petrol dissolve in water? Give two examples. STEP 3 Short Answer Type Questions9. Write any two differences between: (a) Catenation and Allotropy (b) Organic compounds and Inorganic compounds (c) Diamond and Graphite 10. Give suitable reason.(a) There are millions of carbon compounds. (b) Diamond and graphite are allotropes. (c) Carbon is a reducing agent. (d) Methane is an organic compound. (e) Sodium chloride is an inorganic compound.
364 NOVA Science Book 9 Modern Concept Science and Technology11. Draw the atomic structure of carbon. Show its electronic configuration. 12. Write four physical properties of carbon.13. Describe the bonding nature of carbon in brief. 14. What are the characteristics of the inorganic compound? 15. What happens when carbon is heated with lead oxide?16. What happens when carbon reacts with lime? STEP 4 Long Answer Type Questions17. When firewood burns with enough air, smoke does not irritate the eyes, but if the air is less, then smoke irritates our eyes. Explain it with a balanced chemical equation. 18. Study the given concept map and answer the following questions.i. What is allotrope? Write the name of B. ii. If you find a piece of allotrope A, what would you use it for? 19. Study the given feature and answer the following questions. Compound A Compound BIt is made of carbon and hydrogen. It is not made of carbon and hydrogen.Most of them do not ionize in water and cannot pass electricity.Most of them ionize in water and pass electricity. Questions i. Identify compounds A and B as organic and inorganic. ii. Between A and B, which one is an electrovalent compound? iii. Write any four uses of compound A. MCQ a b c d e Answer i iii ii i iv Carbon serves as the fundamental basis of life. Explain the meaning of this statement with a few supporting points. PROJECT WORKCarbonABAllotropehardest allotrope of carbon, conductor of heatSoft and shiny black allotrope of carbon, conductor of heat and electricityFeatures
Modern Concept Science and Technology NOVA Science Book 9 365Dr. Prakash Kumar Paudel is a conservation biologist. He is a senior scientist at the Nepal Academy of Science and Technology and the Kathmandu Institute of Applied Sciences. He has helped in ecological research, biological diversity conservation, humanwildlife interaction, and conservation biogeography, among other areas. Dr. Prakash Kumar PaudelInspiring Nepalese ResearcherAgricultural production decreases every year. Crops are lost due to pests, extreme weather, wild animals, floods, and droughts. Poor seed quality and lack of fertilizer also decrease agricultural production. It is a huge loss to both farmers and the country. It creates a food shortage in the country, making food expensive and causing many people to starve. Therefore, we must use suitable technology and methods to increase food production and store food properly.Questions:i. What are the various issues that decrease agricultural production? List any ten.ii. How can farmers make their own fertilizer using locally available organic materials? Mention its advantages.iii. What do farmers usually use to increase crop production in your locality?iv. Which methods were used by our grandparents to preserve grains traditionally?WARM UP ACTIVITYIntroductionFood is essential for living things. It is the only source of energy for us. We obtain food from plants. We grow crops, fruits, and vegetables in the fields. They obtain nutrients from the soil. If the land lacks nutrients agricultural production decreases. crops in fieldsMATERIALS USED IN AGRICULTUREUNITESTIMATED TEACHING PERIODS19TH PR5 2
366 NOVA Science Book 9 Modern Concept Science and TechnologyWe are supposed to use fertilizers to increase agricultural production.Various germs, bacteria, fungus, and viruses are harmful to plants. We should use pesticides, fungicides, and insecticides to get rid of them.Necessary nutrients for plantsFertilizers enhance the growth and development of plants. Plants need three main macronutrients, viz. Nitrogen (N), Phosphorus (P), and Potassium (K), three secondary macronutrients, viz. calcium (Ca), magnesium (Mg) and sulphur (S), and some micronutrients like copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), etc. These macronutrients and micronutrients are found in soil which is absorbed by the roots of green plants.a. Primary nutrientsThe nutrients required for plants in the largest amount are called primary nutrients. Nitrogen, phosphorus, and potassium are the three main nutrients necessary for the growth and development of the plant.b. Secondary nutrientsThe nutrients that are usually needed in moderate amounts compared to the primary nutrients are called secondary nutrients. Calcium, magnesium, sulphur, etc. are some secondary nutrients.FertilizerFarmers use a variety of organic and inorganic substances to increase the fertility of the soil. These substances are called fertilizers. These substances supply nutrients which are essential for the growth and development of plants. Fertilizers are water-soluble substances used in the soil to increase crop production by supplying essential nutrients. A good fertilizer or complete fertilizer always provides essential elements to the growing plants as well as nourishes the micro-organisms.Memory NoteFertilizers account for 50% of global food production consumed by both animals and humans.chemical fertilizer
Modern Concept Science and Technology NOVA Science Book 9 367Fact and ReasonIt is necessary to use fertilizers in the soil, why?When the same types of plants are grown for a long time, the fertility of soil decreases. So, for continuous use of soil and to maintain crop production, it is necessary to use fertilizers.ActivityVisit a nearby vegetable garden with your guardian. Why do the gardeners use fertilizer? Ask them.The population of the world is increasing at a high rate but the productivity of crops is decreasing which will result in a food crisis. Therefore, a variety of fertilizers should be used to increase the productivity of crops.1. Organic FertilizersFertilizers that are obtained from dead, decayed and decomposed parts of animals and plants or their waste products are called organic fertilizers or manure. Organic fertilizers are soil suitable fertilizers. Organic fertilizers are complete fertilizers because they contain nitrogen, phosphorus, potassium, and every other nutrient. There are two types of organic fertilizers or manures.a) Green manure: Green manures are the green plants that are grown, ploughed, and mixed in the soil to provide essential nutrients to the growing plants. Green manures supply essential elements which are required for growing plants and also checking soil erosion. The leguminous and nonleguminous plants are grown, ploughed, and decomposed to get organic matter which is also called humus.b) Compost manure: Compost manure is an organic fertilizer that is made from dead, decayed, and decomposed parts of animals and plants or their waste products. To prepare compost manure, a mixture of dead plants, animals, or their waste products is kept in a pit with altering layers of soil. Sometimes, a little amount of lime is also added to the mixture. Due to microbial action, the mixture gets decomposed into compost green manure
368 NOVA Science Book 9 Modern Concept Science and Technologymanure. It is used in the soil to provide essential elements for growing plants.compost compost pitMemory NoteOrganic fertilizer is a biodegradable fertilizer. So, natural fertilizer (organic fertilizer) does not pollute the environment.Advantages of Organic FertilizerThe main advantages of organic fertilizer are given below:i. It increases the fertility of the soil.ii. It increases the water-retaining capacity of the soil.iii. It helps to control soil erosion.iv. It helps to control environmental pollution.v. It does not affect the quality of the soil.Disadvantages of Organic FertilizerThe major disadvantages of organic fertilizer are as follows:i. It takes a long duration to work.ii. It contains little quantity of nutrients required for plants.Fact and ReasonOrganic fertilizers are soil suitable fertilizers, why?Organic fertilizers are soil suitable fertilizers because they provide all the essential elements to the growing plants without changing the composition of the soil.ActivityCompost is a complete fertilizer. It contains every nutrient necessary for plants. However, it works slower than chemical fertilizer. Take two flower pots with sand and grow a flower in both. Use chemical fertilizer in the first one and compost in the second one. Observe the differences in their growth.
Modern Concept Science and Technology NOVA Science Book 9 3692. Inorganic Fertilizers or Chemical FertilizersThe man-made chemical (or inorganic) substances which are added to the soil to increase crop production by supplying essential elements are called chemical fertilizers. Chemical fertilizers (or inorganic fertilizers) supply mostly Nitrogen (N), Phosphorus (P), and Potassium (K) as the chief elements. They are needed for growth, development, and seed production. Based on the elements present, there are three types of chemical fertilizers.They are:i. Nitrogenous fertilizersii. Phosphorus fertilizersiii. Potassium fertilizersThe fertilizer that contains nitrogen, phosphorus, and potassium is also called NPK fertilizer.nitrogenous fertilizer potassium fertilizer phosphorus fertilizera. Nitrogenous fertilizers:Fertilizers that contain nitrogen are called nitrogenous fertilizers. For example,i. Urea [NH2CONH2]ii. Ammonium sulphate [(NH4)2SO4]iii. Ammonium nitrate [NH4NO3]iv. Calcium cyanide [Ca(CN)2]Importance of nitrogen (Nitrogenous fertilizer)Nitrogen helps in the formation of protein, protoplasm, and chlorophyll in plants. It is a single fertilizer. It contains only one nutrient. It is essential for rapid growth and to yield more crops. Deficiency of nitrogen results in poor development of flowers, fruits, and seeds. Leaves become yellow and flowers do not bloom properly.
370 NOVA Science Book 9 Modern Concept Science and TechnologyMemory NoteNitrogenous fertilizer is necessary for plants if the leaves are yellow and the flower does not bloom properly.Fact and ReasonWhy does wind break down maize plants if too much urea is used in thefields?If too much urea is used in the fields, then only the shoot system will grow faster whereas roots remain weak due to the lack of phosphorus. As a result, the maize plant breaks when the wind blows.b. Phosphorus fertilizers:Fertilizers that contain phosphorus are called phosphorus fertilizers.For example,i. Ammonium phosphate [(NH4)3PO4]ii. Calcium superphosphate [Ca(H2PO4)2.2CaSO4]iii. Triple superphosphate [3Ca(H2PO4)2]iv. Bone mealImportance of phosphorus (Phosphorus fertilizer)Phosphorus helps in the ripening of fruits and the development of seeds. It is also important in the synthesis of protein, cell division, and growth of leaves and buds. Phosphorus also helps to resist diseases.Memory NoteIf plants have poorly developed roots, then phosphorous containing fertilizer is necessary for these plants.Fact and ReasonWhy is bone used to make fertilizer?Bone is a tissue present in the animal’s body. It is very rich in salts of calcium and phosphorus. Since bone can supply calcium and phosphorus to the plants, it is used as a fertilizer.c. Potassium fertilizers:Fertilizers that contain potassium are called potassium fertilizers. For example,i. Potassium chloride (KCl)
Modern Concept Science and Technology NOVA Science Book 9 371ii. Potassium nitrate (KNO3)iii. Potassium sulphate (K2SO4)iv. Potassium carbonate (K2CO3)Importance of potassium (Potassium fertilizer)Potassium helps in the photosynthesis and growth of flowers. It also helps in protein synthesis, cell division, food production, etc. Due to deficiency of potassium, leaves, and buds wither and immunity is also reduced.Advantages of Inorganic (Chemical) FertilizersThe major advantages of chemical fertilizers are as follows:i. Chemical fertilizers are easy to collect and transport from one place to another.ii. They contain most of the nutrients essential for the growth and development of plants.iii. They are water-soluble. So, they can be absorbed by plants easily.iv. Different single fertilizers can be mixed and used according to the need.Memory NoteChemical fertilizers are good for immediate results in the growth, development, and productivity of plants.Fact and ReasonDespite the harmful effects, chemical fertilizers are widely used.The chemical fertilizers are harmful but they are widely used because they are easily dissolved in water and absorbed by plants.Disadvantages of Chemical Fertilizersi. Chemical fertilizers cause environmental pollution.ii. They increase the acidity or alkalinity of the soil.iii. They affect the quality of the soil.Activity• Pay a visit to farmers in your locality.• Ask the technique of making compost manure and green manure to the farmers.• Prepare a short report and submit it to your science teacher.• Also, prepare a list of inorganic or chemical fertilizers that are used in your locality.
372 NOVA Science Book 9 Modern Concept Science and TechnologyConservation of soil qualityPlants grow well in fertile soil. Soil loses its quality due to erosion, sewage, chemical fertilizers, and unscientific agriculture. We can conserve the quality of soil by following methods.i. Plant treesThe plants prevent soil erosion and landslide. They prevent decrease in the quality of the soil.ii. Build terraceThe terrace reduces speed of running water. It prevents soil erosion.iii. No-till farmingAvoid till farming because it kills earthworms and soil loses organic materials.iv. Contour ploughingContour ploughing is the method of ploughing across the contour lines of the slope. This method helps in slowing the water and preventing erosion.v. Crop rotation Continuous cultivation of the same crop imbalances the fertility of the soil. Crop rotation is the method of growing a series of dissimilar crops in the area. It helps to improve soil structure and make it fertile.vi Maintain soil pHPlants grow well on soil with suitable pH. We should test the pH of the soil. It allows us to know the missing nutrients from the soil. We can treat the acidity or alkalinity of soil by using suitable chemicals.vii. Water the soilProper irrigation prevents soil erosion.InsecticidesThe chemical compounds that are used to kill or control harmful insects are called insecticides. In our surroundings, several insects and pests are present. Among them, some are beneficial, whereas some are harmful. Some insects harm plants, crops, domestic animals, human beings, etc. Therefore, poisonous chemicals are terrace farmingContour ploughing
Modern Concept Science and Technology NOVA Science Book 9 373manufactured to control them. Those chemicals either kill or disturb the life cycle of harmful insects and decrease their number.Memory NoteThe most commonly used insecticide is malathion. It is an insecticide against mosquitoes.Types of insecticidesInsecticides are classified as bio-insecticides and chemical insecticides.a. BioinsecticidesThe pesticides made from natural materials that are meant to kill or control insects are called bioinsecticides. They may be prepared from animals, plants, bacteria, or minerals. They control insects by non-toxic mechanisms. Bioinsecticides are less toxic. They decompose quickly. They do not pollute the environment. They do not kill good insects and earthworms. They are usually made from plant parts.Memory NoteBioinsecticides are good insecticides. The insecticides that are less toxic, degradable and do not pollute the environment.b. Chemical insecticidesMan-made poisonous chemical compounds that are used to kill or control harmful insects are called chemical insecticides. In our surroundings, several insects and pests are present. Some insects harm plants, crops, domestic animals, human beings, etc. Therefore, poisonous chemicals are manufactured to control them. Those chemicals either kill or disturb the life cycle of harmful insects and decrease their number.Examples: BHC (Benzene hexachloride), DDT (Dichloro diphenyl trichloroethane), Aldrin, Dieldrin, Methoxychlor, etc. are organic chemical insecticides. Calcium arsenate, lead arsenate etc. are inorganic chemical insecticides.Advantage of insecticidesi. Increased crop production.ii. Protection from defoliation.iii. Prevents diseases.iv. Prevents spoilage of stored food.v. Controls insects from the crops.
374 NOVA Science Book 9 Modern Concept Science and TechnologyDisadvantage of insecticidesi. Poison can get into food.ii. They kill good insects such as spiders and earthworms.iii. They pollute land and water.iv. They can cause cancer in human beings.v. They can kill aquatic animals.Fact and ReasonWhy should we not use chemical insecticides?We should not use chemical insecticides because they kill not only the harmful insects but also the good ones. They also cause diseases in human beings.Precautions while using insecticidesSince insecticides are poisonous, they should be used with caution:i. They should be kept in a closed container and labelled properly.ii. They should be used in the recommended doses.iii. People using pesticides should fully cover their body and wear a gas mask.iv. Users should not eat or drink while using pesticides.v. Fruits should not be plucked and eaten right after using pesticides.1. Primary nutrient: The nutrients required for plants in the largest amount is called primary nutrient. 2. Secondary nutrients: The nutrients that are usually needed in moderate amounts compared to the primary nutrients are called secondary nutrients. 3. Fertilizers: Fertilizers are those water-soluble substances that are used in the soil to increase crop production by supplying essential nutrients. 4. Organic fertilizers: Fertilizers that are obtained from dead, decayed and decomposed parts of animals and plants or their waste products are called organic fertilizers or manure. 5. Complete fertilizers: The fertilizers that contain nitrogen, phosphorus, potassium, and every other nutrient required for plants are called complete fertilizers. Terms and terminologies
Modern Concept Science and Technology NOVA Science Book 9 3756. Green manures: Green manures are the green plants that are grown, ploughed, and mixed in the soil to provide essential nutrients to the growing plants. 7. Compost manure: Compost manure is an organic fertilizer that is made from dead, decayed, and decomposed parts of animals and plants or their waste products. 8. Chemical fertilizers: The man-made chemical substances that are added to the soil to increase crop production by supplying essential elements are called chemical fertilizers. 9. Nitrogenous fertilizers: Fertilizers that contain nitrogen are called nitrogenous fertilizers. 10. Phosphorus fertilizers: Fertilizers that contain phosphorus are called phosphorus fertilizers. 11. Potassium fertilizers: Fertilizers that contain potassium are called potassium fertilizers. 12. Insecticides: Chemical compounds that are used to kill or control harmful insects are called insecticides. 13. Bioinsecticides: The pesticides made from natural materials that are meant to kill or control insects are called bioinsecticides. 14. Chemical insecticides: The man-made poisonous chemical compounds that are used to kill or control harmful insects are called chemical insecticides. 15. Organic insecticide: The carbon-containing man-made chemical compounds that are used to kill or control harmful insects is called organic insecticide. 16. Inorganic insecticide: Insecticides that are made from minerals are called inorganic insecticides. Terms and terminologies
376 NOVA Science Book 9 Modern Concept Science and TechnologyEXERCISESTEP 1 Multiple Choice Questions1. Choose the best answer from the given alternatives. a. Which of the following are organic fertilisers? i. Urea, DAP, Compost ii. Compost, green manure, bone meal iii. Nitrogen, phosphorus, potassium iv. Ammonium sulphate, urea, bone meal b. A farmer notices that the leaves of his crops are turning yellow. He wants to choose a fertiliser that will provide immediate results. Based on the table below, which option should he choose?Suitable for root Suitable for shoot Organic fertiliser A BChemical fertiliser C Di. A ii. Biii. C iv. D c. Why should farmers use biopesticides? i. It kills all insects in contact. ii. It makes the soil fertile. iii. It does not harm humans. iv. It is a chemical fertiliser. d. I am fertiliser. I help in disease resistance. Who am I?i. Nitrogen-containing fertiliserii. Phosphorus-containing fertiliser iii. Potassium-containing fertiliseriv. Calcium-containing fertiliser e. Which activity does not conserve the soil? i. Contour farming ii. Terrace farming iii. Crop rotation iv. Chemical fertilisersSTEP 2 Very Short Answer Type Questions2. Define the following terms. (a) Primary nutrients (b) Secondary nutrients (c) Fertilisers (d) Organic fertilisers (e) Complete fertilisers (f) Green manure (g) Compost manure (h) Chemical fertilisers (i) Nitrogenous fertiliser
Modern Concept Science and Technology NOVA Science Book 9 377(j) Phosphorus fertilisers (k) Potassium fertilisers (l) Insecticides (m) Bioinsecticides (n) Chemical insecticides (o) NPK fertilisers 3. Name any two primary nutrients and secondary nutrients essential for the growth and development of plants.4. What are the precautions for using insecticide? 5. Namaste! I am Sita. I have started organic farming. I use compost fertilisers in fields to grow vegetables. Vegetables are healthier and fresher. I do this so that I can have non-toxic vegetables for my family. Questions What are the four reasons that she switched to using compost fertiliser?6. Farmers complain that if urea fertiliser is used more in plants, plants grow very tall and fall during winds. Explain the possible reason behind it.STEP 3 Short Answer Type Questions7. Write any two differences between: (a) Primary nutrients and Secondary nutrients(b) Fertilisers and Insecticides (c) Organic fertilisers and Chemical fertilisers(d) Compost and NPK (e) Nitrogenous fertilisers and Phosphorus fertilisers 8. Give suitable reason.(a) If the soil lacks phosphorus, the winds uproot the maize plants. (b) The use of compost manure should be promoted over chemical fertilisers.(c) We should use bioinsecticides instead of chemical insecticides. (d) Chemical fertilisers and insecticides are a source of chemical pollution. (e) NPK is called a complete fertiliser. 9. Write any two effects on plants due to a deficiency of nitrogenous fertilisers.10. Write down the importance of phosphorus fertilisers. 11. What are the advantages of insecticides? 12. Write any three precautions while using chemical fertilisers.13. Various chemical materials, such as fertilisers and pesticides, are used to deal with problems related to agriculture. It helps to improve agricultural production. Make a list of a few problems due to which farmers are forced
378 NOVA Science Book 9 Modern Concept Science and Technologyto use chemical fertilisers and pesticides. 14. Plants need …… for growth and development of the body. Plants need …… in large amounts. Among them, potassium is a metal and the other two are non-metals. Questionsi. What is being discussed in the text above?ii. Mention the names of the other two elements along with their primary function.STEP 4 Long Answer Type Questions15. Explain the use of chemical fertilisers and their impact on the environment.16. Side effects of chemical fertiliser are now easily seen in the fields. The soil is becoming acidic, and agricultural production has decreased. What can be done to save the fertility of the soil and increase crop production? Write in detail.17. Study the given fact and answer the following questions.There was a shortage of diammonium phosphate (DAP) in Nepal in November 2024. As a result, the plantation of winter crops like pulses, wheat, and mustard was delayed. It is likely to decrease production and increase the price of food. QuestionsWhat is a fertiliser? What harm does the shortage of fertilizer bring to the country? 18. Study the given concept map and answer the following questions. Degradable, less soluble in water, less amount of nutrients Fertilizer Non-degradable, highly soluble in water, more amount of nutrients A BQuestions i. Which one is compost manure, A and B? ii. Write any two advantages of A.iii. Write any two disadvantages of B.MCQ a b c d e Answer ii iv iii iii iv Let’s suppose you want to make a compost fertiliser. How would you do it? Prepare a PowerPoint slide to demonstrate the steps for making compost fertiliser.PROJECT WORK
Modern Concept Science and Technology NOVA Science Book 9 379Source:S.N. Name of Scientists Source of Biography Source of Photo1. Dr. Padam Sundar Malla https://en.wikipedia.org/wiki/Padma_Sundar_Mallahttps://upload.wikimedia.org/wikipedia/commons/d/db/Padma_sundar_malla.jpg2. Dr. Jiban Shresthahttps://www.linkedin.com/in/jiban-shrestha47231677/?originalSubdomain=nphttps://media.licdn.com/dms/image/v2/D5603AQGoSBC2-g7TUg/profile-displayphoto-shrink_200_200/profile-displayphoto-shrink_200_200/0/1710206099807?e=2147483647&v=beta&t=NoWKzP7ZPg-1hH_nNJhdiFYW6oYR2R0ikrbyJ5Zd7aA3. Dr. Ram Prasad Chaudhary https://twas.org/directory/chaudhary-ramprasad https://twas.org/directory/chaudhary-ram-prasad4. Dr. Pramod Kuma Jha https://twas.org/directory/jha-pramod-kumar https://twas.org/sites/default/files/styles/fellows_ya_photo/public/cropped_photo_p_k_jha_2020.jpg?itok=AH-u6VpC5.1 Dr. Sunil Kumar Joshihttps://kmc.edu.np/academic-wing/departments/dotor-profile/dr-sunil-kumarjoshi/ https://kmc.edu.np/media/images/MicrosoftTeams-image_2.width-400.jpg5.2 Dr. Birendra Kuma Bista https://www.emedevents.com/speaker-profile/birendra-kumar-bistahttps://www.emedevents.com/speaker-profile/_next/image?url=https%3A%2F%2Fstatic.emedevents.com%2Fuploads%2Fspeakers% 2F200%2Facf16ca9470e990fa70831412d306d8e.png&w=256&q=705.3 Dr. Kumud Dhital https://en.wikipedia.org/wiki/Kumud_Dhital https://www.healthcareradius.in/cloud/2021/11/15/Dr.-Kumud-Kumar-Dhital,Program-and-Surgical-Director-ofthe-Institute-of-Heart-and-Lung-Transplantation.YashodaHospitals.jpg6. Dr. Madan Koiralahttps://www.researchgate.net/profile/MadanKoirala-3#:~:text=About&text=Madan%20Koirala%20is%20a%20Professor,EGEA)%20from%20Tribhuvan%20University%20Nepal.&text=Professor.,Council%20of%20Government%20of%20Nepal.https://i1.rgstatic.net/ii/profile.image/675812286164998-1538137613644_Q128/MadanKoirala-3.jpg7. Dr. Sudarshan Karki https://sudarshankarki.wixsite.com/skarki/about-mehttps://media.licdn.com/dms/image/v2/C5603AQHYoxFnWgB3fg/profile-displayphotoshrink_800_800/profile-displayphoto-shrink_800_800/0/1659578623867?e=1748476800&v=beta&t=eMcDaAyyriOF121Rzy88-otFptzDVXhvOka3OsGhhUE8. Dr. Shobhakar Dhakal https://en.wikipedia.org/wiki/Shobhakar_Dhakal https://ait.ac.th/wp-content/uploads/2021/12/use-this890x1024-1.jpeg9. Dr. Ramesh Kumar Maskey https://peeda.net/ec-members/dr-rameshkumar-maskey/https://peeda.net/wp-content/uploads/2023/01/RameshMaskey-2.jpg10. Dr. Tara Nidhi Bhattarai https://ndri.org.np/profile/prof-dr-tara-nidhibhattaraihttps://ndri.org.np/storage/website/team/OUdNGJpqjFiwWbRCoDK7WRD6adlNeAZPlt0pQt3G.jpg11. Dr. Hari Ram Shrestha https://birds4.birds-project.com/hari-ramshresthahttps://birds4.birds-project.com/wp-content/uploads/2019/05/Hari-251x300.jpeg12. Dr. Aavash Maskey https://unisec-global.org/abhas.html https://unisec-global.org/img/abhas.jpg 13. Dr. Shankar Prasad Shrestha https://en.wikipedia.org/wiki/Shankar_Prasad_Shresthahttps://tribhuvan.academia.edu/ShankarShrestha/CurriculumVitae 14. Dr. Achyut Adhikari https://cdc.tu.edu.np/staffs/details/2355 https://portal.tu.edu.np/medias/Achyut_sir150x150_2024_07_01_17_49_05.jpg 15. Dr. Basanta Giri https://icbb.com.np/icbb2022/speakers2022/basant-giri/?utm_source=chatgpt.com https://i0.wp.com/icbb.com.np/wp-content/uploads/2019/11/basant-giri-e1632066393654.png?w=800&ssl=1 16. Dr. Bhola Thapa https://en.wikipedia.org/wiki/Bhola_Thapa https://hrd.ku.edu.np/Position-Holders/current-vicechancellor/ 17. Dr. Bijaya K. Shrestha https://independent.academia.edu/BijayaShrestha2https://0.academia-photos.com/12398107/147222565/136771837/s200_bijaya.shrestha.jpg18. Dr. Surendra Shrestha https://doece.pcampus.edu.np/index.php/drsurendra-shrestha/https://doece.pcampus.edu.np/index.php/dr-surendrashrestha/19. Dr. Prakash Kumar Paudel https://conbio.kias.org.np/team-member/details/154 https://conbio.kias.org.np/uploads/post/74961573640404.jpg
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