Chapter – 1 Nutrition in Plants Worksheet 1 1. a. iv) b. iii) c. iv) d. ii) e. ii) 2. Pitcher plant Sundew Venus flytrap 3. a. cells b. sun c. carbohydrate d. algae e. hots 4. a. True b. False c. False d. True e. True 5. a. Because the food we eat has nutrients which provide us energy. b. Because in green plants, chlorophyll needs sunlight to prepare food. c. Because these white or brown patches are fungi which need moisture to grow. d. Because it prepares its food by photosynthesis as well as traps insects to feed on. 6.

Sunlight Oxygen

Glucose Carbon dioxide

Roots Minerals

Water

7. a. 6CO2 (Carbon dioxide) + (6H2O (water) C6H12O6 (sugar) + 6O2 (oxygen). b. It indicates presence of starch and hence the accurrance of photosynthesis. c. Cuscuta is also called Amarbel. It follows parasitic mode of nutrition. d. Because it is a major component of chlorophyll which is essential for photosynthesis. 8. a. Because green plants prepare their food themselves by the process of photosynthesis in presence of sunlight, carbon dioxide and water. b. Lichens are the symbiotic associations of algae and fungi. They cannot grow in polluted area containing sulphur dioxide hence they disappear from such areas. c. Oxygen is released by the green plants during photosynthesis which human beings and all other animals need for breathing. d. For the process of photosynthesis, chlorophyll containing cells of leaves trap light energy 1 from the sun, carbon dioxide from the air and water and minerals from the soil to synthesis carbohydrates. e. (i) In parasitic nutrition, one species (parasite) benefits while the other species (host) is harmed. On the other hand in symbiotic nutrition, both the species live mutually and are benefitted. (ii) In autotrophic nutrition, organisms make food themselves from simple substances. Therefore, plants are called autotrophis. In heterotrophic nutrition, organisms take in food prepared by plants. 9. Lid

Leaf modified into pitcher

a. Pitcher plants prepare food by the process of photosynthesis. But in absence of sunlight and for nitrogenous needs, their leaves, which are modified in pitchers, trap insects. Inside pitcher, there are hair which entangle the trapped insects and the lid closes. The insect is killed by the juices secreted in the pitcher and its nutrients ate absorbed. b. i. Mushroom Bread mould ii. Saprotrophic nutrition: These are fungi which absorb nutrients from dead and decaying matter. iii. Hot and humid weather conditions are required for the growth of these organisms. c. No blue-black colour observed on performing iodine test on a dry leaf indicates that there is no starch present in the leaf. 10. Unlike manufactured fertilizers, natural organic manures improve soil quality and promote crop growth. They act slower and gentler as compared to manufactured fertilizers. Besides, continuous application of fertilizers to the soil decreases its fertility and also increases activity of the soil.

2 ACTIVITY ZONE

S.No. Plants Mode of Nutrition

1. Venus flytrap Partial heterotrophic 2. Mushroom Saprotrophic 3. Neem Autotrophic 4. Cuscuta Parasitic 5. Pitcher plant Partial heterotrophic 6. Mistletoe Parasitic 7. Lichens Symbiotic 8. Rose Autotrophic 9. Rafflesia Parasitic 10. Blue-green algae Autotrophic

Worksheet – 2 1. a. starch b. fungus c. carbon dioxide, oxygen d. rhizobium e. stomata 2. a. iv) b. iii) c. v) d. ii) e. i) 3. a. Chlorophyll b. Saprotrophic c. Iodine solution d. Stomata e. Amerbel 4. a. iii) b. iii) c. iii) d. i) e. iii) 5. a. True b. False c. True d. True e. True 6. Algae Fungus

autotrophs heterotrophs

Grass Mushroom

Plants Cuscuta

7. a. Saprophytes are the plants, fungi or microorganisms that live on dead and decaying organic matter. b. Because starch is created from the products of photosynthesis. c. It is water movement through a plant and its evaporation from aerial parts like leaves, stems. d. Carbohydrate (glucose) and oxygen.

3 8. a. i. Parasitic – Cuscuta, Mistletoe ii. Insectivorous – Pitcher plant, Venus flytrap iii. Saprotrophic – Mushroom, Breadmould iv. Autotrophic – Neem, Pipal b. Because chlorophyll is present in leaves only which is an essential component of photosynthesis (food making process). c. i.

Nucleus

Thin outer wall Chloroplast

Guard cell Vacuole

Thick inner wall Stomatal pore

ii. Stomata help in transpiration. They help in photosynthesis and exchange of gases. b. Rhizobium bacteria, living in the root nodules of leguminous plant, convert the atmospheric nitrogen into soluble form like nitrate and nitrite so that plants can take them up from soil. Thus, it enriches the soil and makes it fertile thereby helping the farmers. e. A – Nucleus: It is a distinct, centrally located spherical structure. B – Cytoplasm: It is a jelly-like substance surrounding the nucleus. C – Cell membrane: It is a thin outer boundary enclosing the cell. 9. a. i. A host is harmed by the parasite while the parasite lives in or on the host and benefits by deriving nutrients at the expanse of the host. ii. Stomata are the openings on plant leaves while guard alls are the kidney or bean shaped cells that surround these openings or stomatas. b. 4. A potted plant is left out in the sun for a few hours. 2. A leaf is plucked from the plant. 1. The leaf is boiled in water. 3. The leaf is boiled in alcohol. 5. The leaf in washed and few drops of iodine solution are added to it. 10. The statement is justified as plants use food mode by themselves. Herbivorous eat plants. Those who eat herbiores are dependent on plants indirectly. Thus, the food made

4 by plants is used by the entire living world. ACTIVITY ZONE

A. a. Stomata b. Leaves c. Cuscuta, Partial paraite d. Saprophytic, Pitcher plant B. a. Oxygen b. Pea c. Algae d. Amino acids

Chapter – 2 Nutrition in Animals

Worksheet – 1 1. a. Stomach b. small intestine c. Camel d. 32 e. alkaline 2. a. True b. False c. False d. False e. False 3.

Buccal cavity

Salivary gland Oesophagus

Liver Stomach Gall bladder Pancreas Large intestine Small intestine

Anus Rectum

4. 12 a. Amino acids b. Pseudopodia c. Cellulose d. Gall bladder e. Cud 5. a. iv) b. iv) c. ii) d. i) e. iii) 6. a. Because different types of taste buds are present on tongue for testing. b. Because bacteria causing tooth decay use sugar from food to produce acids. c. Because it protects the inner layer of stomach from acid. d. Because of absence of certain bacteria which digest cellulose in cattle. 7. a. It helps to create food bolus by moistening food. It also has enzyme amylase which hydrolysis starch in to sugar. b. To get rid of food left over after the nutrients are removed from it.

5 c. In small intestine. d. Since glucose can be easily absorbed in blood. e. The digested food mslecules are carried a rounded the body to where they are needed. 8. a. During assimilation the absorbed substances are transported via blood vessels to organs where they are used to build complex substances like proteins required by the body. b. It kills many bacteria that enter along with food and makes the medium in the stomach acedic and helps digestive juices to act. c. It is small intestine that has millions of villi which increase surface area for food absorption. Within these which many blood vessels are present that absorb digested food. d. It is pancreatic juice when containas a variety of enzymes. These enzymes assist in breakdown of proteins, fats and carbohydrates for further processing and absorption in the intestines. e. (i) We use tongue for talking. (ii) It mixes saliva with the food during chewing and helps in swallowing food. (iii) We also taste with our tongue. f. Gall bladder in a pear-shaped hollow structure localed under the liver and on the right side of abdomen. It stores and concentrates bile which plays an important role in fat digestion. 9. a. i. 1. Incisors 2. Canines 3. Premolars 4. Molars ii. 1. Incisors – For biting and cutting 2. Canines – For piercing and tearing 3. Premolars – For chewing and grinding 4. Molars – For chewing and grinding also b. Rumen

Small intestine

Large intestine

Oesophagus Caecum

Stomach

Reminants swallow grass and store it in a part of stomach called rumen. The food here is partially digested and is called cud. Later this cud returns to the mouth in small lumps 6 and the animal chew it. This is called rumination. Bacteria present in rumen help in digestion of cellulose. c. i. Stomach sereates hydrochloric acid digestive juices. The acid kills bacteria and makes the medium acidic. Digestive juices break down proteins into simpler substances. ii. In small intestine, the surface of millions of villi absorbs the dighted food materials. iii. In large intestine, water and some salts from the undigested food materials are absorbed. 10. a. Diarrhoea b. Bacteri infection or food poisoning may be cause of this disease. c. To take plenty of fluids and ORS solution (or a mixture of a very small amounted of a very small amounted of salt and sugar dissolved in water). ACTIVITY ZONE

Type of food Mode of feeding

Blood Sucking Nector of flowers Siphoning Small animals Swallowing Nector of flowers Sucking Blood Sucking Leaves and insects Scraping Food particles Chewing

Worksheet – 2 1. a. iv) b. ii) c. i) d. iii) e. ii) 2. a. v) b. i) c. iv) d. vi) e. ii) f. iii) 3.

Bitter

Sour

Salt Sweet

7 4.

Food is taken into the body by the process of ______.ingestion

Salivary glands release salivary______amylase which breaks down starch into ______.sugars

On moving down the food pipe, food reaches ______.stomach

Digestive juices in stomach are:

Gastric______lipase ______Pepsin ______Renin

The complete digestion of food takes place in ______.small intestine

Large intestine absorbs _____water and ______salts from the undigested food.

The undigested food is moved out from the ______.anus

5. a. taste buds b. Stomach c. Dental floss d. Liver, pancreas e. Enamel 6. a. Milk teeth Permanent teeth ⇒ Milk teeth are the first set of teeth ⇒ Permanent teeth are the second set that grow during infancy. of teeth that replace milk teeth. ⇒ They fall off at the age from six to ⇒ These teeth may test throughout life eight years. or fall off during old age or due to some dental disease.

8 b. Morals Premolars ⇒ Molars have four cusps or points. ⇒ Premolars have two cusps or points. ⇒ Molars are slightly larger in size then ⇒ Premolars are slightly smaller in size premolars. that molars. ⇒ These are present in the rear of the ⇒ They are present between canines mouth. and molars. 7. a. It is break down of complex components of food into simpler substances. b. To protect the lining of the stomach from acid. c. These increase surface area for absorption of food. d. Since fat globules in goat's milk are smaller than in cow's milk. e. It helps to create food bolus by moistening food. It also has salivary amylase which hydrolysis starch into sugar. 8. a. Fats are digested in small intestine. Bile juice breaks down large globules of fat into smaller globules. This is called emulsification of fats. The bile also makes medium alkaline so that the pancreatic enzyme containing lipase further digest fats to form fatty acids. b. Digestion of cellulose takes longer time because the enzymes are produced by the ruminant bacteria that live in the gut of herbivore. Longer small intestine ensures that food stays for a longer duration and proper digestion is possible. c. A– Oesophagus: Muscles of oesophagus contract to move food to the stomach. This is called peristalsis. B– Stomach: It sereates mucus, hydrochloric acid and digestive juices which help in digestion. d. Salivary gland– It produces saliva which keeps mouth and other parts of digestive system moist. Saliva also breaks down starch into sugars. Liver– It processes the nutrients absorbed from small intestine. It secretes bile which helps in fat digestion. Pancreas– It secretes pancreatic juice which acts on carbohydrates, fats and proteins and changes them into simpler forms. e. Tooth decay is the damage of teeth. It we do not clean our teeth and mouth after eating, many harmful bacteria begin to grow in it. These bacteria break down sugars present from the left over food and release acids. These acids gradually damage the teeth causing tooth decay. To prevent tooth decay one should clean teeth with a brush and dental floss twice a day and rinse the mouth after every meal. One should not put unwanted objects in the mouth. f. i. Ingestion in the process of taking food into the body whereas egestion is the process of removing faecal matter through the anus. ii During absorption, the digested food passes into blood vessels in the wall of intestine while assimilation is the transportation of absorbed substances via blood vessels to

9 various organs of the body where they are used to build complex substances. 9. Nucleus

Food particles Pseudopodium (ingestion)

Egested waste Food vacuole Amoeba

a. Amoeba pushes out pseudopodia around food particle and engults it which becomes trapped in a food vacuole. Digestive juices are secreted into food vacuole which break down food into simpler substances. The digested food is absorbed and is used for growth, maintenance and multiplication. Undigested resides of the food is expelled out side by the vacuole. b. i. Test tube A shows blue-black colour while test tube. B does not show this colour. ii. Chewing had made food into smaller particles and salivary amylase has mixed with it. iii. It indicates that salivary amylase present in saliva has broken down starch into simple sugars so no blue-black colour in observed in test tube B. 10. Because salivary amylase present in saliva breaks down starch into simple sugars.

ACTIVITY ZONE

1. 9. P A N C R E A S 8. M F 2. 3. 10. T O N G U E A N U S E E I 4. 11. 12. B I L E S C X A I A E 5. V I L L U S 13 14. C E I C 6 S O U R V U 7. W A C I D

10 Chapter – 3 Fibre to Fabric Worksheet –1 1. a. sheep wool b. herbivorous c. sericulture d. China e. shearing 2. S.No Name of breed Quality of wool 1. Marwari Coarse wool 2. Nali Carpet wools 3. Bakharwal Woollen shawls 4. Patanwadi Wool for hosiery 5. Rampur bushair Brown fleece 3. a. True b. True c. False d. False e. True 4. a. Morus b. Mulberry c. Shearing d. Reeling e. Sheep f. Marwari 5. a. iii) b. ii) c. iv) d. iv) e. iii) f. ii) 6. Yak Camel Llama Goat 7. a. It is the process of selecting parents for obtaining special character in off spring. b. Jammu and Kashmir. c. It is the process of taking out threads from the cocoon for use as silk. d. Shearing. e. It is soft, lustrous and elastic. 8. a. Because it enables sheep to survive without their protective coat of hair. b. A caterpillar completely covers itself by silk fibres and turns into pupa. This covering is called cocoon. Cocoons are immersed in boiling water to separate out silk fibres. c. i. Scouring : Sheared skin with hair is throughly washed in tanks to remove grease, dust and dirt. ii. Sorting : Hairy skin is sent to a factory where hair of different textures are separated. iii. Dyeing : The fibres are dyed in various colours. d. The workers may develop respiratory diseases like asthma and bronchial ailments. There is an increased risk of developing lung cancer. Skin irritation, ulcers, sensitisation and allergic contact dermatitis may also develop in workers in silk industry.

11 e. Female Male

Cocoon Eggs on mulberry leaves Cocoon with developing moth

Silkworm

9. a. (i) The fleece of sheep along with a thin layer of skin is removed (Shearing). (ii) It is throughly washed in tanks to remove grease, dust and dirt (Scouring). (iii) Hairy skin is sent to a factory where hair of different textures are sorted (Sorting). (iv) Small fluffy fibres (burrs) are picked out. The fibres are again scoured and dried. (v) The fibres are dyed in different colours. (vi) The fibres are straightened, combed and rolled into yarn. b. The cocoons are kept under the sun or boiled or exposed to steam. The silk fibres separate out. The threads from the cocoons are taken out for use as silk. It is called reeling the silk. It is done in special machines. Which unwind the threads or fibres of silk from the cocoons. 10. Natural fibre will burn with a flame while artificial fibre will melt.

ACTIVITY ZONE a. FACRYL IC

RSOJ SONP

ASTUVIYK

YZTWO OLD

ONOOK SOK

NENI LHNJ

YH JUTEKU

AFDH JKMN

12 WORKSHEET–2 1. a. Lohi b. scouring c. caterpillar d. Kashmiri goat e. mulberry 2. a. iv) b. iii) c. i) d. ii) e. i) 3. a. FLEECE b. SHEARING c. COCOON d. SERICULTURE e. SILKWORM f. SORTING 4. Eggs Silkworm Cocoon Adult 5. a. False b. False c. True d. False e. True 6. a. Since a sorter may get infected by a bacteriun, anthrax, which causs a fatal blood disease (sorter's disease). b. Because fibre obtained from this moth is soft. Lustrous and elastic and can be dyed. c. It is done to separate out the silk fibres. d. Because wool fibres are obtained from animals and rien in proteins. 7. a. Sorter's disease. b. Because the uppermost layer of the skin is dead. c. Wool and silk. d. Lohi, Rampur bushair, Nali and Marwari. e. The longer fibres are made into wool for making sweaters. 8. a. White fleece of the lamb is meant by white coloured hair of the lamb. b. Since the skin of caterpillars never grows and it becomes too tight when their body grows. c. Since caterpillar have stingy hair which can cause irritation. These hair and their body fluid can sometimes be poisonous too. Also, heat transfer their body can be fatal for them. d. Grass, leaves a mixture of pulses, corn, jowar, oil cakes and minerals. In winter, they are fed on leaves, grain and dry fodder. e. Its salivary gland starts secreting a sticky fluid, a protein called fibroin. This fluid hardens on exposure to air and forms a long thread of silk. This thread gets wrapped around its body to form a ball-like structure called cocoon. 9. a. Caterpillars grow in size and when the caterpillar is ready to enter next stage called pupa, it weaves a net to hold itself. Then it swings its head from side to side and secretes fibre made of a protein which hardens on exposure to air and becomes silk fibre. Soon the caterpillar completely covers itself by silk fibres and turns into pupa. b. i. Scouring by machines : A machines is used to throughly wash the sheared skin and remove grease, dirt and dust from it. ii. Scouring in tanks : The sheared skin with hair is throughly washed in tanks to remove grease, dust and dirt. This is known as scouring.

13 iii. Shearing : The fleece of the sheep along with a thin layer of skin is removed from it body. This process is known as shearing. 10. Synthetic silk (rayon) is produced in mills, is produced in bulk at one time and needs less labour and skills a while pure silk is produced by silk worms. It requires a lot of skills, labour and time to treat the worms and extract silk from them. Hence synthetic silk is cheaper then the pure silk.

ACTIVITY ZONE

Type of flame Odour Bright flame Odour of burning paper Bright flame Odour of burning leaves/wood Bright flame Odour of burning paper Orange sputtery flame Odour of burning hair or feathers Low flame Odour of burning hair/meat Melts/No flame Odour of celery Melts/No flame Odour of slightly sweet chemical

Chapter – 4 Heat

WORKSHEET–1 1. a. iii) b. ii) c. iv) d. ii) e. i) 2. a. Celsius b. faster c. Clinical d. convectione convection 3. a. True b. False c. False d. True e. True 4. Ice - cold Sun - Hot Volcano - Hot Fire - Hot Tea - Hot Glowing bulb - Hot Ice - cream - cold Lemonade -cold 5. Wash it with antiseptic solution

Ensure mercury level is below 35°C Hands it with care Precautions

Do not hold it by the bulb Keep mercury level along eyesight

6. a. Conductors Insulators These are the materials which allow heat These are the materials which do not to pass through them easily. allow heat to pass through them easily. For example : copper, aluminum, iron. For example : plastic, rubber.

14 b. Clinical thermometer Laboratory thermometer ⇒ It is used to measure body ⇒ It is used to measure the temperature temperature. of objects. ⇒ Temperature range is 35°C – 42°C. ⇒ Temperature range is – 10°C – 110°C. 7. a. (i) Object should besolid (ii) Tempreture difference should be there b. Because metals are good condition of heat. c. Because convection currents need movement of particles. d. 35°C – 42°C e. Conductor - Copper, Insulator - Plastic 8. a. Because mercury has high coefficient of expansion so the slightest change in temperature is notable when used in thermometer. It has a high boiling point which also makes it suitable to measure high temperature. b. Heat from the sun reaches the earth by radiation. The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. c. Because the clinical thermometer is designed to measure the temperature of human body only and the temperature of human body normally does not go above 42°C. d. Temperature is a reliable measure of the hotness or coldness of an object. Celsius (C) and Fahrenheit (F) are the two units in which it is measured. e. It is so because atoms / molecules is solids are located closer together. Metals are the best solids for conducting heats having lightly backed atoms. 9. a. A Sea breeze : During day time, the air over land becomes hotter and rises up. Cooler air from sea rushes in towards land. The warm air from land moves towards sea to complete the cycle. The air from the sea is called sea breeze. B Land breeze : At night, water cools down more slowly than the land. So cool air from the land moves towards the sea,This is called land breeze. b. Conduction : (i) Heating of utensils while cooking. (ii) Heating of metallic plate in electric iron. Convection : (i) Cooling system in a car radiator. (ii) Convection currents causing air to move and hence affecting the climate. Radiation : (i) Heat from the sun reaching earth. (ii) Heat felt by a frame. 10. Because it produces quick cooling in the room. This is so since cooled air from AC comes down and the warm air from below rises up and a convection current is set up.

15 ACTIVITY ZONE Observations : When in sun, water in glass with black surface has high temperature as compared to water in glass with while surface. When in shade, water in glass with while surface has high temperature comparatively. Conclusion : Glass with black surface has absorbed more heat compared with white surface when in sun. When in shade, black surface has lost more heat in comparison with while surface. Inference : Dark surfaces of objects absorb more heat compared with light surfaces which reflect most of the heat. Dark surfaces lose heat faster compared with light surfaces. Worksheet –2 1. a. O°C, 100°C b. 98. 6°F c. Mercury d. convection e. Radiation 2. a. iii) b. v) c. ii) d. i) e. iv) f. vi) 3. a. Temperature b. Conduction c. Joule d. Insulators e. Laboratory 4. a. i) b. iii) c. iv) d. iii) e. iv) 5. Conduction Convection Radiation 6 Aluminium Air

Plastic Steel

Silver

Conductors Rubber Insulators

Iron

Glass Copper

7. a. From the hotter and colder end to the object. b Principle of thermal expansion, i.e., when a substance gets hotter, it expands. c. Kink prevents mercury level from falling on its own. d. Radiation 8. a. Because insulators are poor conductors of heat, due to which they do not get heated

16 and we are able to hold the utensils with their help. b. Heat is the energy that flows between two objects that are at different temperature while temperature is a measure of how hot or cold a substance is. c. Mass, temperature difference, specific heat capasity of the substance, nature of material (conductor or insulator) extent of contact are the factors. d. (i) Convection (ii) Radiation (iii) Convections e. Type : Clinical thermometer Digital thermometer Laboratory thermometer Range : 35°C – 42°C 35°C – 45°C –10°C – 110°C 9. a. (i) To receive the cooler sea breeze. (ii) Because light colours absorb less heat as compared to dark colours. (iii) Since mercury has high coefficient of expansion and slightest change in temperature is notable. (iv) Because atoms/molecules in solids are located closer together. (v) A kink is present near the bulb of thermometer which prevents mercury from falling and rising. b. The figure shows the process of conduction. It this, a few metal rods are placed on a tripod. A few small pieces of wax are fixed on rods and one end of rods is heated. Wax pieces near flame fall first and the farthest at last which shows that heat is transferred from the hotter and to the colder end of an object.

10. Since a clinical thermometer is designed to measure only human body temperature having a temperature range of 35°C to 42°C.

ACTIVITY ZONE

BCELSIU STST SMGATUMB ETH IKINKNGQMM E NO SDRSHOPER SEABREEZERM UQFRREAARCO LLMEKPTTAUM AMEECURYTRE TCXZOD IJUYT OWNEVLZURHE RHERMOMN EYR

17 Chapter – 5 Acids, Bases and Salts

Worksheet –1 1. a. acidic b. synthetic c. neutralisation d. curd e. blue 2. Litmus Turmeric China rose 3. a. Sodium hydroxide b. Magnesium hydroxide c. Calcium hydroxide d. Sodium hydroxide e. Ascorbic acid f. Sodium hydroxide 4. a. ii) b. iii) c. i) d. v) e. iv) 5. S. No. Indicator Colour in acids Colour in bases 1. Litmus Red Blue 2. Turmeric Yellow Red 3. China rose Dark pink Green 4. Phenolphthalein Colourless Pink 5. Methyl orange Red Yellow 6. a. Because antacid contains magnesium hydroxide which neutralies the effect of excessive acid. b. Because mineral acids are highly corrosive. c. Because soap solution is basic in nature. d. Because organic matter releases acids which neutralise's basic nature of soil. 7. a. Natural - Turmeric, china rose, synthetic - Phenolphthalein, methyl orange. b. Because all these contain acids. c. Hydrochloric acid d. Sodium chloride and water are produced (neutralisation reaction). e. Acids turn blue litmus red. 8. a. These are specific type of substances which are used to test whether a substance is acidic or basic. Turmeric and china rose are natural indicators. b. These wastes contain acids. If they are directly flushed info water bodies, the acids will kill fish and other organisms. c. Salt and water are produced and heat is evolved. It is called a neutralisation reaction. d. The rain containing excess of acids is called acid rain. Rain becomes acidic because carbon dioxide, sulphur dioxide, and nitrogen dioxide dissolve in rain drops to from

18 carbonic acid, sulphuric acid and nitric acid. Acid rain causes damage to buildings historical monuments, plants and animals. e. On adding turmeric, sodium hydroxide will red. Other two liquids will turn yellow. Add red coloured solution to two yellow liquids. One yellow liquid will change red colour of sodium hydroxide info yellow colour. This liquid is hydrochloric acid. The other liquid in sugar solution. f. S. No. Substance Taste (sour / bitter / Acid / Base other) 1. Leman Juice Sour Acid 2. Vinegar Sour Acid 3. Grapes Sweet Acid 4. Caucumber Other Base 5. Curd Sour Acid 6. Baking soda Bitter Base 9. a. In this activity, 2 - 3 drops on phenolphthalein indicator are added to acid. Now, sodium hydroxide solution is added to the acidic solution till pink colour appears. On adding one more drop of hydrochloric acid, it becomes colourness. On more drop of sodium hydroxide changes it pink. Thus on mixing acidic and basic solutions both neutralise effect of each other (Neutralisation reaction). b. (i) Since excess of oily and spicy food leads to acidity and indijestion which causes pain. (ii) Hydrochloric acid was produced. (iii) It was an antacid. (iv) Milk of magnesia and Alka - seltzer 10. Sample A should be treated with powdered chalk as turns blue litmus solution red and is acidic in nature. Chalk reduces acidity of soil. Sample B should be treated with manure since blue litmus has no effect on it and so it is basic in nature.

19 ACTIVITY ZONE

I show red colour with acid, I am princess of the kitchen, But no change with base. Can be used as an antibiotic or antiseptic. I am prepared from a symbiotic plant, Shows reddish brown colour with soap, Can you guess my name? But with acid there is no hope.

______Litmus ______Turmeric

I am product of Acid-base reaction, Neither sour nor bitter, Can you identify my nature?

______Salt

When stomach produces more acid, I am colourless with acid, You can use me as an antacid. but pink with base. I am your friend in the kitchen, I am an indicator, Also used in fermentation. Identify me and get grace.

______Backing soda ______Phenolphthalein

Worksheet – 2 1. a. iv) b. iii) c. iv) d. iii) e. iii) 2. Oxalic acid Lactic acid Sodium hydroxide Citric acid Sodium bicarbonate Tartaric acid Formic acid Citric acid 3. a. iii) b. iv) c. i) d. v) e. ii) 4. Lemon juice Tomato Soap Acids Bases

Soda water

water Baking soda Lime Grapes

20 5. Excessive use of ______chemical fertilisers

Soil becomes too ______acidic or ______basic

Acidic soil Basic soil

Treated with ______sulphur

Treated with ______lime Treated with chalk______powder_

6. S. No. Substance Acid / Base present 1. Vinegar Acidic acid 2. Lime water Calcium hydroxide 3. Milk of magnesia Magnesium hydroxide 4. Ant,s Sting Formic acid 5. Tamarind Tartaric acid 6. Orange Citric acid 7. Window cleaner Ammonium hydroxide 7. a. It will turn red. b. Formic acid c. (i) Spinach (ii) Lemon d. Pink colour 8. a. On adding phenolphthalein, an acid gives pink colour while a base remains colourless. b. Salts are produced during neutralisation reaction in which an acid and a base are reacted. c. Sulphuric acid in used in manufacturing fertilisers. Sodium hydroxide is used in manufacturing soap and detergents. d. Since acids will react with metals forming metal salts and liberating hydrogen gas. e. The reaction between an acid and a base is called neturalisation reaction. Salt and water are produced with evolution of heat. Example : Reaction between hydrochloric acid and sodium hydroxide produces sodium

chloride and water. HCI + NaOH → NaCl + H2O 9. a. Antacids are a class of medicines that neutralise acid in the stomach. They contain ingredients such as calcium, magnesium or sodium bicarbonate which act as bases actas 21 bases to counteract stomach acid and make its pH more neutral. b. The waste of many factories contain acids. These acids will kill fish and other aquatic organisms and they are allowed to flow into the water bodies. These factory wastes are neutralised by adding basic substances. c. Bases : Ammonia is used in the production of fertilisers, aluminium hydroxide is used in making gastric medicine - antacid, and calcium hydroxide is used in making cement and lime water. Acids : Strong acids like sulphuric acid, are used in mineral processing, nitric acid/ sulphuric acid are used in fertilisers, sulphuric acid in used in batteries. 10. Take china rose petals in a beaker, add warm water in it and keep for some time till water becomes coloured. This coloured water is an indicator which turns acidic solution to dark pink (magenta), basic solution to green and with distilled water, no colour change.

ACTIVITY ZONE

7. P 1. 8.A C I D C N 2. B L U E K T 9. 10. 5. S I B L 3. 6. L A C T I C A C I D L A T A C T C T L H I E C E 4. R E D R I N U M

Chapter – 6 Physical, and Chemical Changes

Worksheet –1 1. a. physical b. reversible c. faster d. galvanisation e. crystallisation

22 2. S. No. Change Changes in Physical prop- Reversible / Irrevers- erty ible 1. Cutting an apple Change in shape, size Irreversible 2. Making ball with Change in shape Reversible clay 3. Drying clothes Change in weight Reversible 4. Churing of milk Change in state Irreversible 5. Freezing of water Change in state Reversible 6. Making a dress Change in shape Irreversible 7. Tearing paper Change in shape, size Irreversible 8. Crushing plastic Change in shape, size Reversible bottle 3. a. False b. True c. True d. False e. True 4. a. Physical b. Chemical c. Physical d. Physical e. Chemical 5. a. ii) b. ii) c. iii) d. iv) e. iii) 6. a. Chemical changes b. Galvanisation c. Crystallisation d. Megnesium oxide e. Light green 7. a. The process of plating one metal onto another by hydrolysis to prevent corrosion. b. It makes the water slightly alkaline.

c. Ca (OH)2 + CO2 → Ca CO3 + H2O d. Since substances are changed into different substances. Combustion and oxydisation occur. e. Presence of air and moisture. 8. a. Water pipes are galvanised (zinc coated) to reduce the corrosive attack by water. b. Yes. Because enzymes in the stomach and intestines break down large molecules into simpler molecules so that body can more easily absorb the food. c. Melting of solid wax to from liquid wax and evaporation of liquid wax to form wax vapour are physical changes. The burning of wax vapour is a chemical changes. d. Take water in a beaker and add a few drops of dilute sulphuric acid and heat it. When it boils, add copper sulphate powder and stir it. Continue adding copper sulphate solution till no more powder can be dissolved. Filter the solution and allow it to cool. Crystals of copper sulphate will be seen at the bottom of the beaker. e. Physical changes do not produce any new substances after the reaction, for example tearing of paper, while chemical changes produce one or more new substances and energy is either given off or absorbed, for example, conversion of milk into card. 23 9. a. Iron displaces copper form solution which gets deposited as a red brown residue. Blue coloured solution changes to light green due to the formation of ferrous sulphat. It is a

displacement reaction. Fe + CuSO4 → Fe SO4 + Cu b. Nail will from rust in test tube A because water and air need for rust formation. In test tube B, oil layer will prevent air from reaching nail and in test tube C also moisture/ water is absent. So no rust formation will take place in test tubes B and C. 10. Because rusting of iron occurs if iron comes in contact with moist air and in coastal areas, air contains high percentage of moisture because of sea or ocean, rusting occurs faster in coastal areas.

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S. Activity Change Evolution Reversible / Physical / No. in colour of gas Irreversible Chemical changes 1. Burning of paper Yes Yes Irreversible Chemical 2. Dissolution of sugar No No Reversible Physical in water 3. Heating of wax No No Reversible Physical 4. Reaction of lemon No Ye s Irreversible Physical juice with baking soda 5. Reaction of iron nails Ye s No Irreversible Chemical with copper sulphate solution Worksheet – 2 1. a. galvanisation b. Copper sulphate c. crystallisation d. permanent e. iron oxide 2. a. ii) b. ii) c. ii) d. i) e. ii) 3. S. No. Change Physical / Chemical Reversible / Irriversible 1. Stretching of rubber band Physical Reversible 2. Glowing of bulb Physical Reversible 3. Burning of wood Chemical Irriversible 4. Rusting of iron Chemical Irriversible 5. Melting of ice Physical Reversible 6. Digestion of food Chemical Irriversible 7. Cutting of wood Physical Irriversible 8. Tearing of paper Physical Irriversible

24 4. a. iii) b. v) c. iv) d. ii) e. i)

5. a. LPG b. CuSO4 c. Inon oxide d. Ozone layer e. Sodium hydrogen carbonate 6. Take a thin strip of ______Clean ______its trip with Bring the tip near ______a candle frame. ______.magnesium ______.sandpaper ______.

Dissolve ______the ash in water It leaves a ______powdery ash which It burns with ______and stir the mixture well. is chemically called ______magnesium ______a brilliant ______.oxide (Mgo) ______.white light

Compound formed on dissolving Test the mixture with ______Red litmus ______blue and red litmus ash in water is ______magnesium hydroxide turns ______.blue ______.papers which is ______basic in nature.

7. a. The arrow (→) in a chemical reaction implies 'becomes'. b. Nonmetallic oxides turn blue litmus red.

c. Magnesium (Mg) + oxygen (O2) → Magnesium oxide (Mgo) d. When baking soda is added to vinegar, carbon dioxide gas comes out. e. Since acids in pickle will react with metal spoiling pickle and carroding metal. 8. a. The formation of manure from leaves is a chemical change because the manure formed has different composition from the leaves. b. The oxidatation reaction causes a sort of rust to develop on fruit, which damages fruit cells, allowing oxygen in air to react with enzyme and other chemicals inside. c. If ultraviolet radiations were not absorbed by the ozone layer it would reach the earth's surface and cause harm to us and other life forms. d. (i) New substances are formed. (ii) Chemical changes are generally irreversible. (iii) Change in cidour / odour / temperature can occur. e. When baking soda is mixed lemon juice, bubbles are formed with the evolution of carbon dioxide. Heat is also evolved. This is a Chemical change. This change is irreversible in nature. 9. a. (i) Prevent iron articles from coming in contact with oxygen or water or both. (ii) Apply a coat oil or grease on the iron object which should be applied regularly to prevent rusting. (iii) Deposit a layer of zinc metal on iron. It is called galvanisation. (iv) Paint the base metal with any durable acrylic paint. 25 (v) Use stainless steel wherever and whenever possible. b. (i) Take a teaspoonful of vinegar in a test tube and add a pinch of backing soda to it.

A hissing sound and bubbles of CO2 gas are produced. Pass this gas through freshly prepared lime water. (ii) When vinegar and baking soda are mixed, a hissing sound is produced and bubbles

of carbon dioxide come out. NaHCO3 + CH3COOH → CH3COONa + H2O +

Co2(g) (iii) Lime water turns milky and calcium carbonate is formed.

Ca (OH)2 + CO2 → Ca CO3 + H2O 10. Changes in both the processes A and B are irreversible and chemical changes.

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5. 6. C B 1. 7. P H Y S I C A L A A K M R I I B N C O G 8. A R N S 2. B L U E D O S I D T O A X 4. M I L K Y D 3. G R E E N

Chapter – 7 Weather, Climate and Adaptations of Animals to Climate Worksheet –1 1. a. iv) b. iv) c. ii) d. ii) e. iii) 2. a. meteorology b. desert c. more d. Siberian crane e. huddle 3. a. True b. True c. True d. True e. True 4. a. 26 Weather Climate The day-to-day condition of the atmosphere The average weather pattern taken at a place with respect to the temperature, over a long time, say 25 year's, is humidity, rainfall, wind speed, etc., is called the called the climate of that place. weather at that place. b. Migration Hibernation Migration is the movement of animals Animals such as frog go on a long sleep from one place to another to escape harsh under the ground to escope the harsh weather, for example, birds like arctic tern weather, which is called hibernation. migrate. 5. Red - eyed frog sticky pads Lion - tailed macaque silver manes / cheek pouches Elephant long trunk Toucan long beak New world monkey prehensile tail Sloth longer arms Gazelle tan colouration Jaguar good swimmer / massive claws

6.

______It has two, thick layers While fur is not easily

______

______of fur which keep it warm in visible in snowy background

______

______cold weather. by its predator and prey.

______It has a very strong

______Curved and sharp claves

______sense of smell which helps

______help it to walk on ice.

______it in locate and catch its prey. ______

______Layer of fat under its

______skin insulates its body from ______cold and keeps it warm.

7. a. Temperature, humidity, rainfall and wind speed. b. Because penguins have features, lay eggs and are warm-blooded but cannot fly. c. Birds migrate to warmer regions when winter sets in and come back after winter is over. d. Latitude, elevation, nearby water, ocean currents, topography, vegetation, prevailing winds. e. Bharatpur in Rajasthan, Sultanpur in Haryana, some wet a lends of north east and some

27 other parts. 8. a. Rain gange is an instrument which measures rainfall. It is basically a measuring cyclinder with a funnel on top to collect rainwater. On the other hond, a weather thermometer measures the air temperature which is a glass tube containing liquids such as alcohol or mercury. b. A very strong sense of smell in polar bear helps it to locate and catch its prey. c. The differences in temperature, pressure, density and moisture content of the air makes on front slides over the other one, which affect weather patterns by creating cloudy skies, thunderstorms and gusty winds. d. Meteorological department of a country prepares weather reports. This department collects data on temperature, wind, etc; and makes the weather predictions. e. (i) It is lion - tailed macaque. (ii) It lives in the rainforests of Western Ghats. (iii) Since it gets sufficient food on tress, it does not come on the ground. 9. a. (i) It is penguin which lives in polar regions. (ii) Their bodies are streamlined and their feet have webs, which make them good swimmers. (iii) (i) It is white coloured so merges well with the white background. (ii) It has a thick skin and a lot of fat to protect it from cold. (iii) Streamlined body and webbed fact make them good swimmer . (iv) Dark-coloured overlapping feathers absorb heat from the sun. (v) Penguins huddle together to keep warm. b. The sun is a huge sphere of hot gases at a very high temperature. The distance of the sun from us is very large. Even then the energy sent out by the sun is so huge that it is the source of all heat and light on the earth. So, the sun is the primary source of energy that causes changes in the weather. Energy absorbed and reflected by the earth's surface, oceans and the atmosphere play important roles in determining the weather at any place. 10. Daily changes in weather are due to winds and storms while seasonal changes are due to earth revolving around the sun. Since earth in round, the sun's rays do not fall evenly on the land and oceans. The sun shines more directly near the equator bringing these areas more warmth.

28

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HA JGCMTQ ITHU URHP SIHEBCVP MX IORGELWL KE IPOLARREGION DDR AIAMPOM PG IGA RNTOHAAYU TK IBFIMA JTZI YTMEOO ENBEEN LFFARNTTNMLC SFAREWE ATHER MR LPSQRA INDO ADAP TAT IONN E

Worksheet – 2 1. a. sun b. climber c. tusks d. hygrometer e. Arctic tern 2. a. iii) b. v) c. iv) d. i) e. ii) 3. Poler bear Penguin Reindeer Fox Seal 4. a. iii) b. iii) c. iii) d. iv) e. ii) 5. Rain gauge Anemometer Hygrometer Barometer Weather thermometer

6.

______Camel stores fat in hump ______Camel can close its

______

_ whith helps it to survive long ______nostrils which keeps out

______

_ periods which food and water. ______blowing sand.

_

______Long strong legs help

______Wide feet help the camel

_

carry______heavy loads and keep

______walk on sand more easily.

_ its______body away from hot sand

______

______Long eyelashes keep sand

_ out______of eyes and thick eyebrows

_ shield______the eyes from desert sun.

29 7. a. In the afternoon b. Tropical region and polar region c. 24 – 26°C in summer and 4 – 10°C in winter d. Penguins prefer to live together in groups to keep warm e. Because of the more heat in tropical regions which leads to evaporation and thus cloud formation, it rain abundantly in there areas. 8. a. Tusks of elephant are used to make billiards balls and piano keys. b. Because they receive a lot of sunlight, there is a lot of energy in rain forests. This energy is stored in plant vegetation which is eaten by animals. The abundance of energy supports an abundance of plant and animal species. c. A - Arctic tern B - Sibarian crane Arctic tern flies from its arctic breeding ground to the antarctic and back again each year, while sibarian crane's eastern population migrates during winter to china and western population migrates in Iran. d. During Earth's orbit in summers the top of the earth (the Northern Hemisphere) is telted towards sun, giving us longer days. In winters, the Northern Hemisphere points away from the sun, resulting in fewer hours of sunshine and shorter days. Therefore, it becomes dark earty in winters. e. (i) The animal shown here is an Indian elephant. (ii) Tropical rain forest. (iii) (i) The long trunk is used by it for picking up food. (ii) Its tusks can tear the bark of trees that it loves to eat. (iii) Large ears keep at cool in hot and humid climate of the rain forest. 9. a. Rajasthan : Climate is hot and dry. Temperature is high during most part of year, but in winter, it is quite low. The region receiver very little rainfall. Kerala : Climate is very hot and wet as it is a coastal area. Kashmir : Climate is moderately hot and wet for a part of year, but extremely cold in winter. Assam : Climate is wet because the north easten India receives rain for a major part of the year. b. (i) Streamlined body makes the animal a good swimmer. (ii) Thick layer of fat insulates the animal's body from cold and keeps it warm. (iii) Two layers of fur keep the animal warm in cold weather. (iv) Strong sense of smell helps the animal to locate and catch its prey. (v) Wide and large paws help to swim well and walk with ease in the show. 10. Bird Toucan possesses a long, large beak which helps it to reach fruits on weak branches. Lion - tailed macaque is a good climber and finds its food on trees. Elephant has long trunk

30 for picking up food and tusks to tear the bark of trees. Some animals have a skin colour which helps tham to camouflage by blending with the surroundings.

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1. 6.H A B I T A T

I B 2. 7. E N V I R O N M E N T 3. 9. P R E Y I D 8. P N G E

R A R F E T A E 4. D I A D A P T A T I O N 5. C A M O U F L A G E I C

T N O E O N

R

Chapter – 8 Winds, Storms and Cyclones Worksheet –1 1. a. wind b. pressure c. eye d. Tornado e. 24 2. a. False b. True c. True d. False e. False 3. Thunderstorms develop in The rising temperatures These winds carry ______water ______hot, humid _ produce ______strong upward ______drop lets up wards ______artropical eas. ______.vising winds ______.

The swift movements of ____the ______falling water droplets There, the water droplelets This event is called a ______freeze ______thunderstorm . along with ______the rising air and ______fall down again. creates ______lightning and ______.sound

4. a. iii) b. iii) c. i) d. iv e. i) 31 5.

Out flow Rising air Sinking air

Stream flow Direction in which Cyclone moving

Eye

6. a. Because air pressure outside the can becomes more than that of inside. b. Because air expands on heating. c. Since warm air is lighter the cold air. d. So that air can pass through three holes, which reduces the air pressure on them. 7. a. Air pressure will reduce. b. Air exerts pressure. Air takes up space and has weight. c. Wind speed is measured by anemometer and wind direction by wind vane. d. Atmospheric pressure is the pressure within the atmosphere of earth. 8. a. Uneven heating on the earth is the main cause of wind movements. b. Light travels faster there fore sound there fore we hear the sound of thunder later. c. Breaker A contains hot water because air expands on heating which makes the balloon inflated. Breaker B contains cold water because air contracts on cooling which makes the balloon deflated. d. Very strong winds can damage houses, buildings, telephones and other communications systems trees, etc., All this causes tremendous loss of life and property. e. Meteorologist around the world use modern technology such as satelites, weather radars and computers, etc. to track cyclones as they develop. 9. a. (i) A cyclone is the formation of a very low pressure system with very high speed winds revolving around it. (ii) Winds from opposite direction meet. This air is heated by warm seas and so evaporates moisture form ocean. This warm air rises up rapidly, cools and condenses to from clouds and produces an area of very low pressure. Cyclones are formed when warm, moist air over the ocean vises upward from near the surface. (iii) A cyclone alert or cyclone watch is issued 48 hours in advance of any expected

32 storm and cyclone warning in issued 24 hours in advance. b. (i) Take a tin can fill it half with water. Heat the can till water boils. Put the lid tightly on the can. Put the can carefully in a washbasin and pour fresh water over the can. (ii) On pouring fresh water over the can, the shape of the can gets distorted. (iii) Their activity proves that air exerts pressure. 10. It is because of air pressure that there is life on earth. Air pressure keeps the water in liquid from around the globe. High air pressure support sunny, clear, and favourable weather conditions, while lower air pressure promotes rainy and cloudy weather conditions. Worksheet – 2 1. a. iii) b. ii) c. ii) d. iii) e. i) 2. a. Eye b. Tornado c. Wind d. Atmospheric pressure e. Typhoon

3. When ______water vapour Before cloud formation, The heat released change back to ______liquid from water takes up ______heat from atmosphere to ______the atmosphere warms as ______raindrops , heat is to takes into ______.vapour the ______air around . released______. to the atmosphere

The chain of events ends with The air tends to More air ______rushes to the the______formation of a very low ______rise and ______.center of the storm pressure______system with very high causes a ______drop speed______. winds revolving around it This cycle is repeated. ______.in pressure

The weather condition is called a ______.cyclone

4. a. Wind vane Anemometer A wind vane is a tool for measuring wind An anemometer is a device to mea- direction. It consists of a horizontal rod that sure wind speed. It uses a series of spins freely around a fixed vertical rod. three or four cups that are posi- tioned around a fixed vertical rod. b. Cyclone Tornado It is large destructive storm that A tornado is a violent storm that comprises strong winds rotating around comprises extremely strong winds centre of low pressure. Cyclone are spiralling around a centre point in a funnel very powerful and can move at 20 - 30 - shaped ciloud. Tornadoes move at 30-40 miles per hour. miles per hour with winds reaching over 300 miles per hour the centre. 33 5. a. high, low b. Warm, cold c. ocean, lend d. reduce e. hurricane 6. Do not drink water that Do not pressurise the could be contaminated. rescue force by making Always store drinking under demands. for emergencies.

Precautions Cooperate and help Do not touch wet your neigubours and switches and fallen friends. power lines. 7. a. India Meteorological Department (IMD) Do not go out just b. Cyclone, Tornado for the sake of fun. c. Since as reaching the land. It loses contact with the humid moisture that feeds. Its strength. d. These develop in hot, humid tropical areas with high temperature. e. Using an anemometer and holding a strip of paper. 8. a. Because high speed winds reduce air pressure above the roof while the air pressure below the roof is high which pushes the thatched roof upwards. b. Because lightning is attracted by the tallest tip of a conductor. If the tip of tree is struck by lightning, the current from lightning may travel down the true and jump towards the human standing under the tree. c. Take two balloons and put a little water into them. Blow up the balloons and tie each one to a string. Hang them 8 - 10 cm apart on a stick and blow between them. They move towards each other since air pressure between them reduces and pressure outside balloons pushes them towards each other. d. In summer, near the equator, the land warms up faster and the temperature of land is than higher that of water in oceans. The air over the land gets heats and rises. This causes the winds to flow from the oceans towards the land. These are called monsoon winds. e. Such design makes air flow rapidly over the wings, which throw air down toward the ground, generating an upward force called lift that overcomes the plane's weight and holds it in the sky. The wings force the air downward and that pushes the plane upward. 9. a. A cyclone is a large destructive storm that comprises strong winds rotating around a center of low pressure. A thunderstorm is the swift movement of falling water droplets along with the rising air creating lightning and sound. While a tornedo is a violent storm that comprises extremely strong winds spiralling around a central point in a funnel - shape cloud. Of these, thunderstorms are most dangerous. Precautions : Cyclone - Do not touch wet switches fallen powerlines. Do not drink water that could be contaminated. Thunderstorm - Do not take shelter under isolated three. Do not sitre near a window. Tornedo - Go to basement or an inside 34 room without windows. Get under something study (a heavy table or workbench). b. (i) The diagram depicts two paper bags hung below burning candle. (ii) This activity concludes that the warm air is lighter than the cold air. (iii) The warm air rises up and purshes the bag above candle. When warm air rises up at a place the air pressure at that place is lowerd. The cold air from the surrounding areas rushes in to fill its space. In this way, this phenomenon sets up convection in air. 10. Cyclones are formed over warm oceans-therefore coastal areas are most likly to face cyclones.

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6. 9. W P 1. 7. 8. A N E M O M E T E R R Y H E M E U S N S D U 2. 3. C Y C L O N E R A I N R E S 4. 10.R O T A T I O N A R 5. W I N D O A M R Chapter – 9 Soil Worksheet –1

1. a. iv) b. v) c. ii) d. i) e. iii) 2.

Humus Water Clay Sand Gravel

35 3. Soil particles Size (diameter) Texture Clay Smaller than 0.002 mm Finest Silt 0.05 to 0.002 mm Smooth / floury Sand 0.05 to 2.0 mm Coarse Gravel Larger than 2.0 mm Large and coarse 4. a. i) b. iii) c. iii) d. iii) e. iii) 5. a. weathering b. Humus c. Sandy d. loamy e. reforestation 6. Soil Crop 1 Crop 2 Crop 3 Sandy Carrot Turnip Maize Loamy Lentils Pulses Cotton Clayey Wheat Paddy Cabbage 7. a. A vertical section through different layers of the soil is called soil profile. b. Because there large spaces between soil particles filled with air. c. Composition, texture and water holding capacity. d. It is the ratio of the weight of water to the weight of solids in a given mass of soil. e. Because loamy soil contains more nutrients, moisture and humus. 8. a. Rate of percolation refers to the amount of water seeping down while the amount of water retained refers to the amount water held. Thus, a higher percolation rate would decrease the amount of water retained in the soil. b. Sandy soil is found in deserts and in other dry areas. It is not preferred for growing plants because it has big soil particles having large spaces between them and it cannot retain water. c. Major components of soil are humus, clay, gravel and sand. Gravel is the heaviest while humus is the lightest component. d. Because topsoil is rich in humus and minerals. This layer is generally soft, porous and can retain more water. So it is a habitat of many living organisms. e. The factors are climate, vegetation, topography, parent material and time. Soil is formed by the process called weathering, which occurs as a result of the action of wind, water, or climatic, or changes. In this process, large rocks break down into smaller pieces. These smaller pieces from soil by mixing with decaying plants and animal parts. 9. a. A horizon : A horizon is the mineral horizon. This horizon froms at the surface and is called topsoil. B horizon : B horizon is mineral subsurface horizon and is a zone of accumulation. C horizon : It consists of parental material like lake sediments that has little or no alteration due to the soil forming processes. 36 D horizon : It consists of at least 20% organic matter by mass. E horizon : E horizon appears lighter in colour. E horizon has lower clay content. b. Soil erosion is the removal of top layer of soil which may occur due to rain, wind, deforestation or any other human activity. It leads to loss of fertile land. It results in increased pollution, and sedimentation in streams and rivers, clogging these waterways and causing decline in fish and other species. Degraded lands are less able to hold on to water which can worsen flooding. To prevent soil erosion, cutting of trees and deforestation should be prevented, and efforts should be made to increase the green areas. 10. All urinal soil, black soil, red soil, desert soil, laterite soil and mountain soil.

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POMABRLQDKY BTEFEUCVCZP HN SQDBGSDO J URHORIZONW F MYAXOS SILTL UGTHCEVLOAM SRZAKGU NIMJ LAHV IWBCSDX IVCLAYEYACK WE ATHERING E MLHPNG JODFK

Worksheet – 2 1. a. False b. True c. False d. False e. True

2.

D horizon

A horizon

B horizon

C horizon Bedrock

37 3. Properties Sand Silt Clay Water-holding capacity Low Medium High Aeration High Medium Low Percolation rate High Medium Low Amount of organic matter Low Medium High to medium 4. a. ii) b. iv) c. iii) d. iv) e. ii) 5. a. Clayey b. Soil erosion c. Reforestation d. Aeration e. Loamy soil 6. Water

Soil Erosion Wind Ice

7. a. Water table is the level below which the ground is saturated with water. b. It is breaking down of rocks by the action of wind, water and climate to from soil. c. Humus is formed of the rotting dead matter in the soil. d. (i) Insecticides and pesticides (ii) Industrial waste e. It is the removal of a forest or trees from land. 8. a. Because overgrazing reduces usefulness and productivity of land. The livestock press the subsoil into fine soil which can be carried easily by water and wind. b. Clayey soil is most suitable for making toys. c. (i) By protecting soil from the impact of rain. (ii) By binding soil to sloping land with their roots. (iii) By transpiring large amounts of water, which counteracts very wet soil. 200ml d. Rate of percolation = = 10 ml/min 20min e. Both physical and chemical weathering describe the process of breaking down of rocks and other rock materials. Both initiate a change in a rock's appearance or composition. 9. a. (i) Soil is considered to be a non-renewable resource because it is a finite resource, meaning its loss and degradation is not recoverable within a human lifespan. (ii) Soil is polluted by human-made chemicals or other alteration in the natural soil. It is caused by industrial activity, agricultural chemicals, or improper disposal of waste. (iii) Because soil provides food, filters air and water and helps to decompose biological 38 waste into nutrients for new plant life. b. Loamy soil is a mixture of sand, clay and silt. It contains humus in it. It has the right water-holding capacity for the growth of plants. 10. These release harmful and toxic chemicals into the soil which can seep into groundwater and also the ecosystem, causing harmful effects.

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5. 6. 7. B C M 1. P E R C O L A T I O N D A I 8. R Y S T 2. O R E T E N T I O N C Y U P K R S 3. E R O S I O N I 4. G R A V E L

Chapter – 10 Respiration in Organisms Worksheet –1 1. Cell surface Stomata Gills Tracheae Lungs Lungs Lungs Lungs / Skin 2. Parameters Aerobic Anaerobic Presence of oxygen Present Absent Amount of energy More energy is released Less energy is released released

End products CO2, Water, energy CO2, alcohol, lactic acid, energy

Word equation Glucose → CO2 + water + Glucose → alcohol + CO2 + energy energy Examples of Humans Yeast organisms 3. a. iii) b. iv) c. i) d. iv) e. ii) 4. 3 4 2 1 5. a. Aerobic b. bronchi c. downward d. haemoglobin e. 15-18 39 6. a. Because less energy is required while sleeping. b. 0.04% c. Lactic acid d. 15-18 times per minute. e. All the floor of the chest cavity 7. a. Because these unwanted particles like dust get past the hair in the nasal cavity and irritate the living of cavity, as a result of which we sneeze. b. On doing so, the roots of plant will not get enough oxygen to breathe as water fills up air spaces present between soil particles. Thus, root will decay and plant will die. c. Because nose has hair which filter out dust particles when we breathe. It also maintains

correct balance of O2 and CO2 in blood. Breathing through mouth may lead to dry mouth. d. Plant leaves have small pores called stomata through which they take in oxygen and give out out carbon dioxide. In cells, oxygen is used to break down glucose into carbon dioxide and water. e. During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of chest cavity and air is pushed out of this lungs.

8. Air is drawn in Air forced out

Ribs move back Ribs move out

Diaphragm moves down Diaphragm moves back (a) Inhalation (b) Exhalation a. Breathing involves inhalation and exhalation. During inhalation, ribs move up and outwards and diaphragm moves down. This increases space in chest cavity and air rushes into lungs which get filled with air. During exhalation, ribs move down and inwards while diaphragm moves up to its former position. This reduces the size of chest cavity and air is pushed out of the lungs. b. A cockroach has small opening on its body called spiracles. It has a network of air tubes called tracheal for gas exchange. Oxygen rich air rushes through spiracles into tracheal tubes, diffuses into body tissue and reaches every cell of the body. Similarly, carbon dioxide from the cells goes into tracheal tubes and moves out through spiracles. 9. In the cells, oxygen in the air we breathe helps in the break down of food. The process of

40 break down of food in the cell with the release of energy is called cellular respiration.

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8. S P 1. 6. 7. D I A P H R A G M I N R 2. 10. E X H A L A T I O N A A O C 3. 9. G I L L E S L A N T E 5. T E R I B S I R I 4. O X Y G E N L

N Y

Worksheet – 2 1. a. anaerobically b. oxygen c. Mucus d. bronchi e. heamoglobin 2. a. True b. True c. False d. True e. False 3. 4. a. Carbohydrate b. 15-18 times c. Diaphragm d. Anaerobic e. Tracheae 5. a. iv) b. vi) c. v) d. ii) e. i) f. iii) 6. a. Because it traps bacteria, other germs, and debris and prevent them from entering lungs. b. We respire to get energy from food. c. Nose, pharynx, larynx, trachea, bronchi, lungs d. Yes, so that the foreign particles we expel are not inhaled by other persons. e. They take in oxygen dissolved in water. 7. a. The atmospheric pressure goes on decreasing as we go above the sea level. So, the amount of oxygen also decreases at higher altitudes. Therefore, mountaineers carry oxygen cylinders with them. b. Aerobic respiration occurs in presence of oxygen while anaerobic respiration takes place in absence of oxygen. More energy is released during aerobic respiration as 41 compared to that in anaerobic respiration. c. Because, during daytime carbon dioxide released during respiration is utilised by the plants for photosynthesis. d. (i) Curve A denotes aerobic respiration because more energy is released. Curve B denotes anaerobic respiration due to release of less energy. (ii) A : Glucose in presence of oxygen → Carbon dioxide + water + energy B : Glucose in absence of energy → Alcohol + carbon dioxide + energy e. (i) Both are pigments (ii) Both are respiratiory organs (iii) Both are conducting passage ways of the respiratory system. 8. a. (i) The activity suggests that the air we breathe out contains carbon dioxide gas. (ii) In test tube B, lime water turns milky. (iii) Ca (OH) + CO → Ca CO + H O 2 2 3 2 b. (i) A person needs artificial respiration at the time of acute breathing problems. It is an artificial method of breathing required when the person is unable to breath normal.

(ii) During artificial respiration, a cylinder filled with oxygen is attached to a machine which provides oxygen for artificial respiration. (iii) It is not provided permanently to every person. It is gives temporarily to person suffering from breething problems. But it can be given permanently to those who are in came or are unable to breathe on his/her own. 9. Thin skin in frogs allows respiratory gases to readily diffuse directly down their gradients between the blood vessels and surroundings. Its moist skin helps to absorb oxygen from the air. ACTIVITY ZONE Inhaled Air Exhaled Air

Oxygen Oxygen ______%21 ______%16.4

Lungs

Carbon Carbon Dioxide Dioxide ______%0.04 ______%4.4

42 Chapter – 11 Transportation in Animals and Plants

Worksheet –1 1. a. plasma b. Arteries, veins c. xylem d. excretion e. haemoglobin 2. a. False b. True c. False d. False e. True 3. Lungs

Pulmonary Pulmonary vein artery Heart Vein Artery

Capillaries

92 4. a. iv) b. v) c. i) d. ii) e. iii) 5. a. iv) b. i) c. iv) d. iii) e. ii) 6.

Right kidney Left kidney

Ureters

Urinary bladder

Urinary opening

7. a. A doctor uses a stethoscope to hear the heartbeat. b. The pulse rate per minute indicates the rate of heartbeat. c. 1-1.8 L per day 43 d. Phloem transports food to all parts of the plant. e. Platelets 8. a. Stomata are tiny pores present on the surface of leaves. Through stomata, water evaporates by the process of transpiration. They help in photosynthesis. b. The root hair increase the surface area of the root for absorption of water and mineral nutrients dissolved in water. The root hair is in contact with the water present between the soil particles. c. The pigment is haemoglobin which binds with oxygen and transports it to all parts of body and ultimately to all the cells. d. The water evaporates through stomata present on the surface of leaves by a process called transpiration. Stomata are triggered to open in light so plants transpire move rapidly during the day. e. (i) A, B and C are veins, arteries and heart respectively. (ii) Because blood flow is rapid and at a high pressure, arteries have thick elastic walls. 9. a. Blood is a fluid which flow in blood vessels. It transports substances like digested food from small intestine to other parts of body. It has various components such as : Plasma – It transports nutrients, hormones and protein to different parts of body. Red blood cells – These contain haemoglobin which binds with oxygen and transports to other parts. White blood cells – These fight against germs that may enter our body. Platelets – These helps in blood clotting. b. When the blood reaches the two kidneys, the useful substances are absorbed back into blood and wastes dissolved in water are removed as urine. From kidneys, urine goes into urinary bladder through tube like ureters. It is stored in bladder and is passed out through the urinary opening at the end of a muscular tube called urethra. The kidneys, ureters, bladder and urethra form the excretory system. 10. If there as no platelets in the blood, the blood would not be able to clot at the wound.

44 ACTIVITY ZONE

6. 1. S 7. P U L S E T H 2. H A E M O G L O B I N T O

H E O M 3. T I S S U E C 8. 9. 10. O B X U 4. C A P I L L A R Y R E O L I 5. O V E I N D M E

95 Worksheet – 2

1. a. ii) b. ii) c. iv) d. iii) e. i) 2. Carbon dioxide Oxygen

Light Water

Water, minerals Oxygen

Carbon dioxide

3. a. Xylem b. sunny c. away from d. increases e. WBCs 45 4. a. Red blood cells White blood cells ⇒ They are celled erythrocytes. They are called Leucocytes. ⇒ They carry respiratory gases main oxygen. They fight against germs. ⇒ Their number is much more than WBC. Their number is much less than RBC. b. Pulmonary Pulmonary vein ⇒ Pulmonary artery carries carbon dioxide- Pulmonary vein carries oxygen-rich rich blood from the heart to the lungs. blood from the lungs to the heart. ⇒ These are one pair in number. These are two pairs in number. 5. 6. a. To transport blood and oxygen from the lungs to various tissues of the body. b. Red blood cells (RBCs), white blood calls (WBSs), platelets c. Right atrium, right ventricle, left atrium, left ventricle. d. Pulse is the throbbing movement fell on the wrist which is due to the blood flowing in arteries. e. Urine contains 95% of water and compounds like urea, creatinine, uric acid, salts of sodium, potassium, calcium, ammonia and magnesium. 7. a. In plants, the vascular tissue xylem forms a continuous network of channels that connects roots to the leaves through the stem and branches and thus transports water to the entire plant. b. When our body temperature increases, our sweat glands produce sweat. It absorbs our body heat and evaporates into atmosphere. Sweat contains water and salts. c. All cells of our body produce waste products. These waste products are toxic to the body and therefore need to be excreted out. d. (i) Upper chambers of heart are called atria. Blood enters the heart through atria. (ii) Lower chamber of heart are called ventricles. Blood exits from heart through ventricles. (iii) These chambers are separated to avoid mixing up of blood rich in oxygen with the blood the blood rich in carbon dioxide. e. Light : Plants transpire more rabidly in the light than in dark. Temperature: Plants transpire more rapidly at higher temperatures because water evaporates more rapidly as the temperature rises. f. (i) Stethoscope (ii) It is used to feel the heartbeats. (iii) A - Earpieces B - Tube C - Chest-piece 8. a. In human heart, blood passes through the heart trice in one cardiac cycle which is called double circulation. In double circulation, blood flows in two pathways : pulmonary and 46 systemic. Pulmonary pathways carries deoxygenated blood from the right side of heart to lungs. Systemic pathway carries oxygenated blood from the left side of the heart to the other areas of body. b. In plants, oxygen – a waste product of photosynthesis and carbon dioxide - a waste product of respiration, diffuse out through the stomata in leaves and cuticles is stems. Excess of water in plants is discarded through stomata by transpiration. 9. Doctor inject medicines in veins, because in veins, medicines camed through the heart and diluted in the blood before reaching a person's extremities and tissues.

ACTIVITY ZONE

GI JVKBLDEMQB WF HEARTOXPAT HAXNEVCUCDED UYCT IJCNRFSI RATRIAPZEYZA IHVIGPLXTARL CIRCULAT IONY AWBLUKTIOLMS CIMETUESNNN I IGSJKRLSQDOS DLTSFQEUPRPX YHVURETERWO E

Chapter – 12 Reproduction in Plants Worksheet – 1 1. a. Flower b. Fertilisation c. Spirogyra d. Fern e. Leaves 2. Pollen grain Stigma

Style Pollen tube

Ovule Ovary

Sperm cell

47 3. a. embroyo b. spores c. eyes d. Maple e. Xanthium 4. a. Asexual Sexual reproduction In sexual reproduction, plant can In sexual reproduction, new plants are give rise to new plant without obtained from seed. seeds. Both parents (male and female) are Only a single parent is involved. involved. b. Embryo Zygote An embryo is the later stage of In sexual reproduction, male and zygote. Zygote develops and forms female gametes fuse and a zygote is an embryo. formed. 5. Binary fission Multiple fission Spore formation Budding Prudding Fragmentation Refenevation Binary fission 6. a. iii) b. iv) c. iv) d. iii) e. ii) 7. a. A flower which contains either only pistil or only stamens is called unisexual flower. b. Sexual reproduction and asexual reproduction. c. A zygote is the primary cell which is formed after fusion of male and female gametes. d. They are transferred by means of wind, water, insects or animals. e. Coconut and water lily. 8. a. It is a type of asexual reproduction in which new plants are produced from vegetative parts like roots, stems, leaves and buds. b. Male– Stamen (anther and filamout) Female– Pistil (stigma, style and ovary) c. A– Plumule, B– Radicle C– Cotyledon, D– Wing d. Through stem– When the rode on a stem comes is contact of soil, it produces roots and new plant. Through root– Roots of guava, sweet potato etc. have adventitious buds which can give rise to new plants. Through leaves– Bry ophyllum has adventitious buds in its leaf margins, which in moist soil, can give rise to new plant. e. If the pollen lands on the stigma of the same flower, it is called self-pollination. If the pollen of a flower lands on the stigma of another flower of the some plant, or that of different plant of the same kind, it is called cross-pollination. 9. a. i. Insects : Many insects feed on seeds and in this process disperse them. Bees inadvertantly carry away sticky seeds. These bees discard the seeds as soon as they can.

48 ii. Wind : Wind comes wing seeds like those of drum stick and maple, light seeds of grasses or hairy seeds of aak and hair fruit of sunflower to far away places. iii. Water : Water disperse fruits or seeds that usually develop floating ability in the form of spongy fibrous outer coat as in coconut. b. A– Cutting : A small piece of vegetatively propagative part of a plant is cut and buried under moist soil, which give rise to new plant. B– Layering : A branch of a plant is bent and burried into the ground, leaving the lip exposed, which produces a new plant. C– Grafting : A shoot (scion) of one plant is cut and attached to the root (stock) to produce new plant. Scion and stock are cut in slanting manner. 10. i. It can be used to reproduced plants that do not have viable seeds. ii. This preserves the characteristics of food and flower crops. iii New individuals produced have exactly identical qualities as their parents.

ACTIVITY ZONE

a. We observe the formation of new yeast cells. b. Budding mode of reproduction is observed. It is asexual. c. Chain of buds Developing bud Yeast cell New bud

Worksheet – 2 1. a. iii) b. iii) c. i) d. i) e. iii) 2. a. gametes b. stamen c. vegetative d. pistil e. zygote 3. Water Animal Animal Wind Wind Wind Insects Wind 4. a. Unisexual flower Bisexual flower The flower which contains either only the pistil The flower which contains both stamens or only the stamens is called unisexual flower. and pistil is called bisexual flower. For example, corn, papaya, cucumber. For example, mustard, rose, petunia.

49 b. Budding Fragmentation Budding occurs when parent forms buds Fragmentation occurs when a parant organism and each bud forms new organism for ex- breaks into fragments or pieces and each ample, yeast. fragment develops into a new organism. For example, spirogyra. 5. a. True b. False c. False d. True e. True 6. Stigma Style Style Stamen

Ovary Petal Sepal

Pedicel

7. a. When water, correct temperature (warmth) and good location (like is soil) are available. b. It is a long, branching filamentous structure of a fungus, the main mode of vegetative growth. c. Cutting, layering and grafting. d. Reproductive part – flower, Vegetative part – stem e. Stamen is a male reproducting organ of flower, consisting of anther and filament. 8. a. These types of plants are reproduced through vegetative propagation. Their stems are capable of vegetative propagation. b. Planaria detaches its tail end and each half regrows the lost parts by regeneration, allowing neoblasts (adult stem cells) to divide and differentiate, thus resulting in two worms. c. Zygote is a diploid cell resulting from the fusion of two haploid gametes. In plants, pollen grain produces male gamete and ovule produces female gamete. These two fuse and form zygote. d. After fertilisation, the ovary grows into a fruit. The other parts of the flower dry up and fall off. The seeds develop from the ovules. The seed contains an embryo enclosed in a protective seed coat. e. When rodes on a stem come in contact of soil, it produces roots and new plant, e.g., potato. Some plants have roots that have adventitious buds which produce new plants, e.g. guava. Some plants have adventitious buds on their leaves' margins, which in moist soil, can give rise to new plant, e.g., bryophyllum. 9. a. i. The process of fusion of male and female gametes to form a zygote is called fertilisation.

50 ii. Pollen grain (germinating)

Pollen tube

Zygote formation

Ovum (a) (b)

The pollen grain falls on the stigma and grows a pollen tube downwards through style towards female gametes in ovary. A male gamete moves down the tube. The pollen tube enters the ovule in ovary. The tip of pollen tube bursts open and male gamete comes out of pollen tube. In ovary, male gametes of pollen fusis with the female gamete present in ovule to form fertilised egg cell called zygote. Thus, the process of fertilisation takes place. b. i. The transfer of pollen from the anther to stigma of a flower is called pollination. ii. Pollination is necessary because it leads to the production of fruits that we eat, and seeds that are essential to create more plants. iii. Self pollination and cross pollination iv. Agents of pollination are animals such as insects, birds and bats, butterflies, wind, water and plants them selves. Since pollen grain are light, they can be carried by wind or water. Many insects visit flowers and carry away pollen on their bodies. 10. After fertilisation in plants, ovules develop into seeds whereas ovary grows into a fruit.

51

ACTIVITY ZONE

HMALPS IAEPCDK D TSRYQKDELRAT DLEBCAGMYUONC EZXANTHIUMXDG ISUIESCNZUBES PPAZLMFEP LFLF UOLYHQDCBEVI J FRAGMENTAT ION OEWO VN JAUOBNG NSATUBERFIJXK APGEHKMNQHWJ P MO SPIROGYRALN

Chapter – 13 Motion and Time Worksheet –1 1. a. periodic b. inversely c. second d. m/s e. independent 2. Straight line Straight line Circular Circular Oscillatory Oscillatory Circular Straight line 3. a. iv) b. iii) c. iv) d. ii) e. i) 4. Speed(Km/h) 0 km/h 40 km/h 40 km/h 40 km/h 40 km/h 5. Sundial Sand clock Water clock 6. a. The to and fro motion of a simple pendulum is called oscillatory motion. b. This graph is straight line parallel to x-axis. c. Circular motion d. Oscillatory motion 250×× 60 60 7. a. i. (a) 250/50 = m/s (b) = 18km/h 1000× 50

52 ii. (a) 60 b. 60 c. 24 d. 365 b. Distance covered in 20 minutes with speed 30 km/h = 10km Then distance covered in 30 minutes with speed 90 km/h = 45km Total distance travelled by the car = 55km c. Uniform – Car moving with constant speed on a straight road, Motion of soldiers during army march Non-uniform – A person jogging and walking, motion of a train d. Time period = 56/20 = 2.8 second e. Vehicle B is moving faster because The distance covered by vehicle B is move on axis which shows distance, as compared to vehicle A. 8. a. i. Motion is the change in position of an object with respect to its surroundings in a given interval of time. Distance travelled ii. Speed = Time taken

iii. Distance Distance Distance

(a) Time (b) Time (c) Time b. i. The states of rest and motion an relative because without any reference object to relate with, it is not possible to mention whether an object is at rest or in motion. Example: Suppose you are travelling in a bus, So to you, all other passengers are at rest. But for a person who is out side the bus, everyone inside the bus is moving. ii. A sundial consists of a flat plate (dial) and a gnomon, which casts a shadow onto the dial, while sand clock has two bulbs connected by a nerrow neck that allows trickle of sand from upper lobe to the lower lobe. iii. These watches are based on quartz. Quartz crystel is electronicall driven. As the crystal vibrates, the watch works in that way. 9. a. Accurate measurement of time become possible much later because time measurement was done it terms of length as distance and mass. For example, position of sun, moon and stars give idea of days, months and years. b. The working principle of all clocks is same, i.e., periodic motion. A sundial measures periodic position of shadow on a dial. A pendulum clock measures number of oscillations of the bob. A spring clock measures back and forth motion of the spring. Aquartz clock measures the number of vibrations or oscillations of the quartz crystal.

53 ACTIVITY ZONE

a. Speed = distance covered/time taken b. Do it yourself c. Do it yourself d. Do it yourself e. Speed is one time measurement of velocity while average speed is the median measurement of different speeds. Worksheet –2 1. a. Non-uniform b. Circular c. Straight line d. Circular e. Oscillatory 2. Pendulum clock Quartz watch Stop watch Atomic clock Mechanical clock 3. a. National Physical Laboratory b. Second c. Non-uniform d. Distance e. Speed 4. a. iv) b. v) c. i) d. ii) e. iii) 5. a. ii) b. iii) c. iii) d. i) e. i) 6. a. Distance – time graph shows the speed. 18×× 60 60 b. Speed = = 64.8km/h 1000 c. Periodic motion is the motion that is repeated after fixed intervals of time. d. Quartz crystals maintain a precise frequency standards which helps to regulate the movement of a clock. e. Average speed = Total distance covered/total time taken 7. a. a. Tortoise = meter/hour b. Horse = kilometer/hour c. Aeroplane = kilometer/hour d. Ant = Meter/hour b. We calculate the average speed of a body when the speed is not constant. c. The speed is the total distance covered divided by the total time taken. Its unit is m/s. It can be expressed in km/h also. d. i. The basic unit of time is second. ii. Larger units = Year and month, Smaller units = Second and minute. e. Distance covered in 20 min = 52415 – 52400 = 15km, So speed = 45km/h Speed in m/s = 45 × 1000/60 × 60 = 12.5m/s

54 8. (A) (B) Y Y

100 100 80 80 60 60

Distance 40 Distance 40 20 20 X X 10 20 30 40 50 10 20 30 40 50 Time Time

i. Object A represents uniform motion. ii. Object A is travelling faster. b. i. The tangent of angle between the line of graph and x-axis. ii. Slope represents speed. Speed is the total distance covered divided by the total time taken. iii. Less steep slope indicates slower speed. iv. More steep slope indicates faster speed. v. The one with more steep slope is faster. 9. i. Graph (i) represents constant speed of the object. ii. Graph (ii) represents object at rest. iii. Graph (iii) represents object with speed which is not constant. iv. Graph (iv) represents object with constant speed.

55 ACTIVITY ZONE 7. 8.. S T U I 5. U N M N D E 2. T I M E I P 6. F D A E 3. O S C I L L A T O R Y R S I M T O 1. A S P E E D N C E 4. M E T E R

Chapter – 14 Electric Current and its Effects

Worksheet –1 1. a. Bulb b. Cell

c. Battery d. Switch in 'ON' position

2. a. low b. can't c. ferromagnet d. battery e. cells

56 3. a. True b. True c. False d. True e. True

4. Light

Heat Sound Uses of electricity Chemical use Mechanical use

5. a. i) b. iii) c. iii) d. iii) e. iv) 6. Bulb

Cell

Key

Wire

7. a. A combination of two or more cells is called a battery. b. Tungsten c. A closed circuit means that switch is 'on', circuit is complete and current is flowing through it. d. MCB is a switch which automatically turns off when current in the circuit exceeds the safe limit. e. A glowing electric bulb may be very hot and our hand may get burnt badly. 8. a. If we place a compass needle near a current carrying wire, it gets deflected. It shows that there is a magnetic field around the wire carrying current. b. The device shown alongside is Miniature circuit breaker (MCB). It is a switch which automatically turns off when current in the circuit exceeds the safe limit. When it is turned on, the circuit is once again complete. c. When electric current passes through a wire, it behaves like a magnet. This is magnetic effect of electric current. In fact, an electric current can be used to make magnets. Electric bell, electric motor, television set are based on magnetic effect. d. i. An electromagnet is a magnet in which magnetic field is produced by an electric current. 57 ii. i. Electromagnets are used in motors and generators ii. These are used in electric bells. iii. Loudspeaker and headphones also use electromagnets. e. i. Length and material of resistor, temperature ii. Transformation of electric energy into light energy and then into heat energy. f. i. A circuit is a path that electricity flows along. It shows various components.

ii. +

9. a. i. It is heating element used in heater. ii. It works on heating effect of electricity. iii. The heating element is used cooking heater. Because of heating effect of electric current, when current is passed through the element, it becomes so hot and produces so much heat that it is able to cook food placed in utensils made of metals which are put over it. b. i. It is electric bell. ii. It's based on magnetic effect of electric current. iii. An electric bell contains an electromagnet, consisting of coils of insulated wire wound around iron rods. When an electric current flows through the coils, the rods become magnetic and attract a piece of iron attached to clapper. The clapper hits the bell and makes it ring. 10. CFLs use less energy, produce very less amount of heat and last longer as compared to ordinary bulbs.

58 ACTIVITY ZONE

10. E 6. 1 S B E L L W E I C 7. 2 T I 8. F I L A M E N T 3. C O N D U C T O R R H S S O 9. U E W M L I A 4. B A T T E R Y G T E N 5. C L O S E D E R T

Worksheet –2 1. a. It becomes hot due to the heating effect of electric current. b. Because copper is a good conductor of electricity that allows the electricity to flow through it easily. c. So that when current in the circuit exceeds the safe limit, it can melt and break the circuit. d. The filament of electric bulb gets heated to such a high temperature that it starts glowing. 2. Sound Heat Light Sound Mechanical Chemical Heat Mechanical 3. a. Compact Fluorescent Lamps b. Indian Standard Institute c. Miniature Circuit Breakers 4. a. i) b. ii) c. ii) d. ii) e. i)

59 5. Heating Effect of Current

Electric bulb Geyser Electric iron

Electric heater Electric toaster

6. Soft iron Hammer armature

Battery Gong

Electromagnet

Switch Coil of wire .

7. a. It is the opposition to the flow of electric current through the conductor. b. The high resistance wire gets heated when an electric is passed through it. c. From positive terminal to negative terminal of battery. d. Low melting point. e. Heating effect and magnetic effect. 8. a. It is required in all electrical appliances to protect them in the event of excessive current which may be due to over loading or short circuit. b. No, we cannot use the same fuse in a geyser and a television set since the electricity rate required by both is different. A geyser needs much more electricity than a television set. c. i. On switching 'ON' the circuit, compass needle shows deflection due to the magnetic effect of electric current. On passing current, wire behaves like a magnet. ii. On switching 'OFF' the circuit, needle comes back to its normal north-south direction, because there is no electric current and hence no magnetic effect. d. Cell Wire Battery Bulb Key e. Heating effect of electric current is used in electric bulb, electric iron and electric fuse. 9. a. i. The activity shows that when electric current is passed through a wire, and a compass is placed near it, the needle of compass deflects from its normal north- south direction. ii. It proves that electric current produces magnetic effect. iii. The two factors are strength of the current and the distance from the conductor/ 60 wire. b. i. Fuse used in electrical appliances ii. It is used for protecting the electrical appliances from excessive current which is beyond the safe limit. iii. The fuse wire, having low melting point, melts and breaks the circuit when the electric current through the fuse exceeds the safe limit due to overloading or short circuit. Thus, it protects the electrical appliances. 10. a. ISI mark is a certification mark scheme, which is operated by Buream of Indian Standards (BIS). The ISI mark ensures that the appliance is safe and wastage of energy is minimum.

ACTIVITY ZONE

1. Electric iron Heating effect 2. Electric oven Heating effect 3. Room heater Heating effect 4. Television Magnetic effect 5. Electric motor Magnetic effect

Chapter – 15 Light Worksheet –1 1. a. straight b. concave c. real d. convex e. dispersion 2. a. True b. False c. True d. True e. False 3. Red

Orange

Yellow

Green

Blue

Indigo

Violet

61

4. a. iii) b. ii) c. i) d. ii) e. iii)

5. Light

Reflection Refraction

Mirrors Lens

Plane Spherical Concave Convex

Concave Convex

6. Nature of Image Same size

Virtual Erect None Behind the mirror at same distance as that of object Laterally inverted Not

7. a. Reflection of light takes place. b. To see an enlarged image of the teeth. c. Violet, indigo, blue, green, yellow, orange, red. d. Concave mirror e. Concave lens 8. a. A real image is always inverted while a virtual image is always irect. Real image is formed when light rays actually meet at some point while virtual image is formed when light rays appear to meet at some point. b. Reflecting surface of concave mirror is buldged inwards while that of convex mirror is buldged outwards. Concave mirror generally produces red, inverted image but convex 62 mirror always produces virtual, irect image. c. Because convex mirrors give an erect, virtual, full size diminished image of distant objects with a wider field of view. Thus, they enable the driver to view much larger area than would be possible with a plane mirror. d. i. The angle of incidence is equal to the angle of reflection (∠i = ∠r). (ii) The incident ray, reflected ray and the normal to the reflecting surface at the point of incidence line in the same plane. ii.

Plane mirror

Angle of Angle of reflection incidence

Reflected ray Incident ray

Normal

e. i. It is the apparent revorsal of the mirror image's left and right when compared with the object. 130 ii. A, H, O, T iii. B, P, D, F 9. a. i. Newton's disc ii. It is based on dispersion of light which as shows that white light is made of seven colours. iii. When the Newton's disc is rotated very fast in the daylight, different colours get mixed together and the disc appear to be whitish. This shows that white light is composed of seven colours, i.e., violet, indigo, blue, green, yellow, orange and red. iv. Rainbow formation in the sky after rain. b. A– Concave mirror : As dentist' head mirror, as reflector in torch B– Convex mirror : As rear-view mirror in vehicles, as reflector in street lamps C– Convex lens : As magnifying glass, as camera lens in cameras 10. By looking into the mirrors, we can distinguish between them. In plane mirror, the size of the image is same as that of the object. In concave mirror, an enlarged image is formed when placed close and an inverted image is formed when kept away. In convex mirror, always a small and irect image is formed.

63 ACTIVITY ZONE 8. C 7. 9. L O V 1. S E V E N I 2. E 6.C O N C A V R 3. O S E R E C T L X U 10. O P A 4. U R E A L 5. R A I N I S S M

Worksheet –2 1. a. i) b. iii) c. i) d. ii) e. ii) 2. a. Plane mirrors Spherical mirrors

• Plane mirrors have flat surface. • Spherical mirrors have curved surfaces. • Plane mirrors always form virtual • Spherical mirrors form both real and image, which is of the same size and at virtual images and the size and distance of the same distance as that of the object. the image varies.

b. Lens Mirrors

• Lens work by refracting light passing • Mirrors work by reflecting light incident on through them. them. • A lens is typically a bent piece of glass • A mirror typically consists of a highly or plastic. polished surface of a metal placed behind a glass.

3. Biconvex Planoconvex Convex meniscus Biconcave Planoconcave Concave meniscus

64 4. a. diverging b. white c. convex d. prism e. converging 5. a. iv) b. v) c. i) d. ii) e. iii) 6. a. Refraction of light b. Virtual, upright, laterally inverted, same size and distance from mirror as the object. c. Because when bulb is placed at focus of concave mirror, it allows light to spread out to infinity (longer distances). d. Angle of incidence is equal to the angle of reflection in a plane mirror. e. So that when the driver of a vehicle ahead of an ambulance looks in his/her rear-view mirror, he/she can read 'AMBULANCE' written on it properly and give way to it. 7. a. It is a band of colours produced by separation of components of light by their different degrees of refraction according to wavelength. VIBGYOR stands for Violet, Indigo, Blue, Green, Yellow, Orange and Red. b. Because a convex mirror converges (bends' inwards) the light generally falling on it whereas a concave mirror diverges (bends outwards) the light falling on it, they are called converging mirror and diverging mirror, respectively. c. The image formed at the backside of the spoon is a virtual image. It is irect and smalled in size. It covers a larger area. d. i. It means that light travels in a straight line as a wave. It can be seen in well-defined shadows formed when an object blocks a light source and through the use of pinhole camera. ii. We can change direction of light by passing it across the boundary between two substances with a different donsity like air and glass (refraction) and by making it fall on smooth surface like mirror (reflection). e. When sun rays are passed through a convex lens and then made to fall on a paper, the paper starts burning at a point which shows converging nature of convex lens. f. Convex mirror Concave mirror Concave mirror Concave mirror Concave mirror Concave mirror 8. a. i. The figure shows a rainbow. ii. The sunlight passes through water particles which act like prisms. When light passes through them, it gets spread out into a bunch of different colours. iii. It is associate with dispersion of light.. iv. A rather low source of light and a layer of water droplets in sky are required for rainbow formation. b. i. In case A will the candle be visible. ii. It suggests that light travels in a straight line. iii. Direction and energy change upon reflection of light. 9. Image in cinema hall projector is real while image in mirror is virtual. Image in cinema hall is inverted while in mirror it is erect. 65 ACTIVITY ZONE

a. THE BAND OF SEVEN COLOURS IS KNOWN AS RAINBOW. b. OUR EACH EYE CONSISTS OF CONVEX LENS. c. SKY APPEARS BLUE DUE TO RELECTION. d. LIGHT IS A FORM OF ENERGY.

Chapter–16 Water : A Precious Resource Worksheet 1 1. a. Infiltration b. 71% c. 2.5% d. 0°C e. 100°C 2. a. True b. False c. True d. True e. True 3.

Hand pump

Stream or lake Recharge

Water table

Aquifer Ground water

4. a. 97% b. level c. Polluted d. Rainwater e. Watercycle 137

66 5. 68°E 72° 76° 80° 84° 88° 92° 96°E

36° INDIA 36°N ANNUAL RAILFALL

PAKISTAN N 32° 32°

CHINA (TIBET) NEPAL 28°

BANGLADESH 24°

I N D I A Tropic of cancer

MYANMAR BAY OF 20° BENGAL 20° ARABIAN RAINFALL IN cm SEA Above 400 16° 200 - 400 100 - 200 60 - 100 12° 40 - 60 12° 20 - 40 LAKSHADWEEP 0 - 20 (INDIA) 8°N ANDAMAN & NICOBAR ISLAND 8°N SRI (INDIA) 72°E 76° 84° 88° 92°E LANKA OCEAN Rain map of India

6. a. iv) b. iii) c. iv) d. i) e. ii) 7. a. 60% b. Because is salty and impure. c. Water table is the level below which the ground is saturated with water. d. Rainwater either soaks into the ground to become groundwater, evaporates or flows over the surface to the land. e. It is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant. 8. a. Because trees release water vapour into the atmosphere, fewer trees will lead to less rain, which ultimately depletes the water table. b. The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration which recharges ground water. c. i. A resource is a source or supply from which a benefit is produced. 67 ii. Renewable resource are the resources which replace themselves naturally in short period of time. They are in unlimited quantity and are environment friendly. E.g., plants, sunlight, air, water. Renewable resources are the ones that are not capable of replacing themselves, in near future. They are in limited quantity and are not environment friendly. E.g., coal, oil, iron. d. Water exists as solid (ice), liquid (water) and gas (water vapour) states. Ice on heating first changes into water and them into water vapour. Water on cooling changes into ice. Water vapour on cooling changes into liquid water. e. Good water management will help reduce the wastage of water and save it in every way possible. Therefore more water will be available for farming purposes and it will be benefited. 9. a. i. Rainwater harvesting ii. It is a simple technique by which rainfall is collected for future usage. The collected rainwater may be stored, utilised in different ways or directly used for recharge purposes. iii. It is useful because rainwater is usually free from harmful chemicals, which makes it ideal for irrigation. It can be purified to make it drinking water and used for daily applications. It is important especially in areas with low water levels. b. Due to increased population, all the facilities like houses, shops, roads, offices, pavements, etc. Increase to fulfill increasing demands. This decreases open area for seepage of water into the ground. Industries require water, so if their number increases, the water required them will also increases which contributes to depletion water table. The main source of water for agricultural activities is ground water which also results in depletion of water table. Thus, increasing population, increasing industries and agricultural activities are the main factors responsible for depletion of water table. 10. • Turn off the tap when not in use while washing hands/face, brushing your teeth, shaving etc. • Shorter your showers as much as possible or use bucket to take bath. • Install a rain barrel as rainwater harvesting is a great way of conserving water. • Fix the leaks immediately when you find them at your home. • If you feel compelled to wash your car, take it to a car wash that recycles the water.

68 ACTIVITY ZONE

Water

Solid Liquid Gas

Snow Ice Water Vapour

RiverOPond Lake cean

Worksheet 2 1. a. 97 b. water table c. Drip d. hydrological cycle e. ice 2. a. True b. False c. True d. True e. True 3.

Hand pump

Stream or lake Recharge

Water table

Aquifer Ground water

4. a. iv) b. v) c. i) d. ii) e. iii) 5. a. i) b. i) c. i) d. i) e. iii) 6. a. 22 March b. It is an abnormal property of water whereby it expands instead of contracting when the 69 temperature goes from 4˚C to 0˚C, and it becomes less dense. c. Because water dissolves more substances than any other liquid. d. Solid form, snow and ice, is present as ice caps at the poles of the earth, snow-covered mountains and glaciers. e. The plants will die if they are not watered for a few days. 7. a. Most of the water of rainfall just flows away which is a wastage of this natural resource. We can recharge the ground water by rainwater harvesting. b. At places the ground water is stored between layers of hard rock below the water table. This is called acquifer. Water in the acquifers can be usually pumped out with the help of tube wells or handpumps. c. Due to increased population, all the facilities like houses, shops, roads, offices, pavements, etc., increase to fulfil increasing demands. This decreases open area for seepage of water into the ground, causing depletion of water table. d. Some places have good amount of rain and are water rich, while some other are deserts with scanty rainfall. Some regions have excessive rains while some others have very little rainfall. Excessive rains cause floods while absence of rains results in droughts. In this way, the distribution of water over the globe is quite uneven. e. Most villages do not have a water supply system. The people fetch water directly from the sources like river, lakes, ponds. Often people and even children have to walk several kilometers to fetch water. The children suffer a lot. They cannot attend school regularly since they spend hours in fetching water. At large number of people draw water from wells, tubewells or hand pumps. 8.

4. Cloud

3. Condensation 7. Precipitation 2. Evaporation

5. Transpiration

6. Infiltration

1. Ground water

70 a. The water cycle starts when water on the surface of earth evaporates due to heat of the sun and changes into gas. Then water collects as water vapour in sky which makes clouds. The water in clouds gets cold which makes it become liquid again. It is called condensation. Then, water from sky falls as rain, snow or hail. This process is called precipitation. The water sinks under surface and also collects into lakes, oceans and aquifers. It evaporates again and continues the cycle. b. i. Flood Drought ii. A flood is an overflow of water that submerges land that is usually dry, while a drought is a natural disaster of below-precipitation in a given region, resulting in prolonged shortages in the water supply. iii. Heavy rains lead to rise in water level of rivers etc. which gets accumulated in coastal areas resulting in flood, while high and water temperatures, cause drought. iv. To prevent flood, construct building above flood levels, restore rivers to their natural course, introduce water storage areas, while to prevent drought, harvest rain, avoid over watering your lawn, install water-efficient irrigation devices, put a layer of mulch around trees and plants to reduce evaporation and so on. 9. If we do not save water now, we will face water scarcity, people will struggle to find fresh drinking water, will face disruptions in food supply, will have less water for crop irrigation, and ultimately it will affect life on earth. ACTIVITY ZONE

KEGWLIQU ID HSNADIEBSC AOFTPADMOR WA TERCYCLE AQDR IPKG IC TUQTTIRLDH EIGA SBWF CA RFSBJLTQ JR HECLOUDS SG TRMERVBNVE

71 Chapter – 17 Forests: Our Lifeline Worksheet 1 1. Neem Sheesham Bamboo Semal 2. Honey

Sealing wax Timber Forest Products

Gum Charcoal

Catechu

3. a. i) b. iii) c. ii) d. iii) e. i) 4. a. lungs b. food web c. food, shelter, oxygen d. crown e. Decomposers 5. a. True b. False c. True d. True e. False

6. Primary Secondary Consumer consumer Grasshopper Frog Sun Water

Grass Tertiary consumer Producer Snake Fungi Hawk

Decomposer Final consumer

7. a. Branches of the tall trees look like a roof over other plants in the forest. This is called canopy. b. Because plants help to provide oxygen for animal respiration, and maintain the balance of oxygen and carbon dioxide in the atmosphere. c. These are organisms that can produce their own food using materials from in organic sources.

72 d. It is the establishment of a forest or stand of trees is an area where there was no previous tree cover. e. These are micro-organisms which convert the dead plants and animals to humus. 8. a. Vulture and hyena are scavengers. They feed on dead and decaying matter so they keep the environment clean by eating out all the waste matter. b. Trees extract water from soil, store it and then release it back into atmosphere by process of transpiration. Deforestation eliminates the water released back into air, thus reduces cloud formation, and therefore reduces rainfall. c. Decomposers recycle and convert the dead matter into humus which mixes with forest soil and provide necessary nutrient to plants. Thus, decomposers help in maintaining the necessary nutrients balance in the soil. d. Food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. Food chains start with plant life and end with animal life. Example: Grass is eaten by grasshopper, grasshopper by frog, frog by snake, snake by hawk. e. During heavy rains, forests act as a barrier to floodwater. Trees also prevent soil erosion, reducing sediment going into rivers and increasing water absorption into the ground. 9. a. We should conserve forests because forest act as a major source of oxygen and sink of carbon dioxide. Forests act as a catchment for soil and water conservation. Forests prevent flood and bring timely rainfall. We can protect forests by controlling over forest fire, regulated and planned cutting of trees, reforestation and Afforestation, proper utilisation of forest and forest products, forest management and cheeking over forest clearance. b. The first layer of forest is canopy which is made of tops of trees. The next layer is understorey which is made of smaller trees (about 65 feet tall). Third layer is shrub layer which is made up of young trees and mature shrubs. The next layer is herb layer which consists of tree seedlings, ferns, grasses. The last layer is forest floor which contains decaying leaves, twigs, fallen trees and other waste. 10. Plants and trees in forests release oxygen through the process of photosynthesis which is used by animals for respiration. Plants consume carbon dioxide released by the animals. Thus they maintain balance of oxygen and carbon dioxide in nature.

73 ACTIVITY ZONE

Snake

Bird Rabbit Eagle

Plant

Worksheet 2 1. a. forest floor b. food chain c. canopy d. Humus e. trees 2. a. renewable b. dependent c. carbon dioxide d. humus e. deforestation 3. a. Because roots of trees in forests help water to seep down in the ground. b. Because green plants produce their own food by the process of photosynthesis. c. Since it is covered with a layer of dead and decaying matters like leaves, fruits, seeds, twigs and herbs.

d. Because plants in forests release O2 and consume CO2 thus maintain their balance. 4. Gum Timber Medicinal Oil Babool Teak Eucalyptus Sandalwood Semal Sal Neem Sunflower Neem Sheesham Dandelion Palm tree

74 5.

a. ______Plants ______Snake

b. ______Plants ______Leopard

c. ______Grass ______Bird ______Hawk

6. a. It affects wild life. It also affects weather patterns. b. Producer– green grass, Consumer – rabbit c. Mustard oil and gum. d. The branchy part of a tree above the stem is known as crown of the tree. 7. a. Endemic species are plants and animals that exist only in on geographic region. Species can be endemic to large or small areas of the earth. b. Agricultural expansion and overpopulation are the two major causes of deforestation. c. Plants and trees consume carbon dioxide and release oxygen during the process of

photosynthesis. Hence, decrease in number of forests will lead to increased CO2 concentration. d. Forests maintain water table by maintaining rainwater flow and by absorbing water via root system of plants. Porous forest soils and debris store the water allowing the slow release of water into surface water. e. Silviculture is the practice of controlling growth, composition, health and quality of forests to meet diverse needs and values. Thus, silviculture helps in conserving forests by growing and cultivating move and more trees. 8. a. Deforestation results in extinction of flora and fauna. It also leads to loss of habitat of animals and their relocation to urban areas. It causes flooding since forests help in controlling floods. Due to deforestation, heavy soil erosion may take place. Moreover, deforestation is the second leading cause of global warming and produces about 24% of global greenhouse gas emissions. b. Forest is called the dynamic living entity because of the presence of various plants, animals and microorganisms. The wide variety of animals helps the forest to regenerate and grow. Decomposers help in maintaining the supply of nutrients to the growing plants in the forest. In other words, forests are the lifeline of forest dwelling communities. 9. The dead plant and animal tissue is converted into humus by the micro-organism. Humus is rich in nutrients. It gets readily mixed with the soil, so that it could be absorbed by the roots of the plants. The dead animals are eaten by the eagles, hawks and vultures. Thus, nothing goes waste in a forest.

151 75 ACTIVITY ZONE

5. 8 D C 1. 1. 7. S E E D D I S P E R S A L F R N O O O 2. R H U M U S P E I Y 3. S C R O W N 6 T O N A X T Y I G 4. F O R E S T N N

Chapter – 18 Wastewater Story Worksheet 1 1. a. liquid b. raw c. Waste d. sanitation e. plants 2. a. True b. True c. True d. True e. True 3. Drinking Cooking

Bathing Uses of

water

generation

power Hydro

Farming

4. a. iii) b. iv) c. iii) d. iii) e. ii)

76

5. Example human faeces, pesticides nitrates, metals phosphorus, nitrogen protozoans, bacteria 6. a. It is the process of wastewater treatment in which pollutants are removed before it enters a water or is reused. b. Human faeces, pesticides and nitrates c. Human faeces, animal waste, oil urea, pesticides, herbicides, fruit and vegetable waste. d. Domestic households, faeces, industrial and agricultural practices produce sewage. e. It is the process of adding chlorine to drinking water to disinfect it and kill germs. 7. a. Because of its excellent disinfection and oxidation qualities, ozone is widely used for drinking water treatment. b. Semi-solids such as faeces that settle down during wastewater treatment are called sludge. This sludge is removed using a scraper and then transferred to a tank where it is decomposed by anaerobic bacteria to produce biogas. c. It is colourless, odourless and tasteless liquid. Freezing point is 0ºc and boiling point is

100ºc. It is a stable substance which is broken into components H2 and O2 when we heat beyond 500ºc. d. Sewage contains human pathogens like cholera, typhoid and dysentery. Other diseases include hepatitis A, intestinal nematode, schisto somiasis. It also leads to water pollutions. e. A skimmer removes the floatable solids like oil and grease. Water so cleared is called clarified water. This sludge is transferred to a separate tank where it is decomposed by the anaerobic bacteria. In this process, biogas is produced which can be used as a fuel or can be used to produce electricity. 8. a. A skimmer removes the floatable solids like oil and grease from sludge. Water so cleared as called clarified water. The sludge is transferred to a separate tank (digester tank) where it is decomposed by the anaerobic bacteria. The biogas produced in the process can be used as fuel. Air is pumped into clarified water in aeration tank to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soap and other unwanted matter still remaining in clarified water. After several hours, the suspended settle at the bottom of tank as activated sludge. b. Good sanitation practices help environment. Clean drinking water and good sanitation help us stay away from diseases. In the same way, eating fresh food and washing hands before eating helps stay from diseases. Therefore, good sanitation practices yield good hygiene. 9. A manhole is the opening to a confined space such as a large vessel, a shaft or a utility vault.

77 Manholes are provided at every 50 m to 60 m in the sewerage, at the junction of two or more sewers and points where there is a change in direction.

ACTIVITY ZONE

RAE RAT ION JBI KNCKBAC TERIA SAEROB ICSISF CEAD JFPHABLI UREASLAONQUL Z OROGPBL IHDT DBLTM EIETTGR GIQCHLOR INEA XCAFWM GAOWHT EMOUXOAYNNUI SYNZ PESTICBO DY SEN TRYVAVN

Worksheet – 2 1. a. iii) b. iii) c. iii) d. iii) e. i) 2. a. sewer b. water pollution c. manhole d. Ozone e. bacteria 3.

Waste water is passed through It is then sent to ______a grit and Water is then ______allowed to settle ______to ______sand removal tank in a large tank called setting______tank remove ______large objects like for removal of sand,______grit which is ______sloped towards rags,______. sticks, plastic packets etc ______.and pebbles. ______.the middle.

Water is sent to ______Floating wastes are removed by Solids like ______faeces skimmer.______. ______separate tanks where settles and are removed with it______is decomposed by _ This water is called ______a scraper. This is ______.the anaerobic bacteria. clarified______. water. ______.the sludge.

Activated sludge is then sent to Water is disinfected with ______sand drying beds wher wheree ______chemicals like ozone______, ______dried sludge ______chlorine and is produced here. ______ultra violet light. .

78 4. a. True b. True c. True d. False e. True 5. a. iii) b. iv) c. i) d. ii) e. v) 6. a. Wastewater is used water from any combination of domestic, industrial, commercial or agriculture activities. b. Sewage is wastewater generated in homes, industries, agricultural fields and in other human activities. c. It is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. d. It is a network of big small pipes which is like a transport system that carries sewage from the point of production to the point of disposal. e. Never pour household products like cleansers, paint, etc., down the drain. 7. a. Because eucalyptus trees absorb all surplus wastewater rapidly and release pure water vapour into the atmosphere. b. Because they can harden and block the pipes. In an open drain, the fats clog the soil pores reducing its effectiveness in filtering water. c. W W T P stands for wastewater treatment plant. Bar screens remove large objects like rags, sticks, cans, plastic packets and napkins. d. Aerobic bacteria are used in treatment plants in an aerated environment. They use free oxygen in water to degrade the pollutants in incoming wastewater into energy they can use for growth and reproduction. Anaerobic bacteria are used to decompose sludge in a separate tank which produces biogas. e. It may cause water pollution and soil pollution. Both surface water and groundwater get polluted. Thus, polluted groundwater becomes the most common route for water- borne diseases. They include cholera, typhoid, polio, meningitis, hepatitis and dysentery. 8. a. Wastewater is passed through bar screens to remove large objects like rags, plastic packets. It is then sent to a grit and sand removal tank for removal of sand grit and pebbles. Water is then allowed to settle in a large tank which is sloped towards the middle. Solids like faeces settle and are removed with a scrapper. This is the sludge. Floating wastes are removed by skimmer. This water is called clarified water. This water is sent to separate tanks where it is decomposed by the anaerobic bacteria. Activated sludge is then sent to sand drying beds where dried sludge is produced. Water is then disinfected with chemicals like ozone and chlorine. b. Sources of water pollution are domestic effluents and sewage, industrial effluents, agricultural effluents, radioactic wastes, thermal pollutants, oil and fat pollution, pesticides, and some others. 9. i. In absence of sewerage system, arrangements for on, site sewage disposal can be made. For example, septic tanks are built in which human excreta are collected ii. Composting pits can be made to dump waste and to make manure from them.

79 ACTIVITY ZONE

7. A 5.. 1. 8. W S E W E R S 6. A U R L S L O U 2. M E T A L S B D E A I G 3. S E W A G E C E A E T A 4. N I T R O G E N

80