202110726-PERFORM-STUDENT-WORKBOOK-SCIENCE-G08-FY_Optimized

6. Combustion and Flame Learning Outcomes • Define the various types of combustion. • Explain the different zones of a candle flamel. At the end of this lesson, students will be able to: • List the requirements of a good fuel. • Define combustion. • Define calorific value. • Identify combustible substances. • Explain the harmful effects of increasing fuel • Define ignition temperature. • Define inflammable substances. consumption on the environment. • List the requirements for producing fire. • Explain the working of a fire brigade. Concept Map CombFulasmtioen and Combustion Flame Fuel Key Points • The substances which burn in air are called • Fuel efficiency is expressed in terms of its calorific value combustible. which is expressed in units of kilojoule per kg. • Oxygen (in air) is essential for combustion. • Unburnt carbon particles in the air are dangerous • During the process of combustion, heat and light are pollutants causing respiratory problems. given out. • Incomplete combustion of a fuel gives poisonous • Ignition temperature is the lowest temperature at carbon monoxide gas. which a combustible substance catches fire. • Increased percentage of carbon dioxide in air has been • Inflammable substances have very low ignition linked to global warming. temperature. • Oxides of sulphur and nitrogen produced by the • Fire can be controlled by removing one or more factors burning of coal, diesel and petrol cause acid rain which is harmful for crops, buildings and soil. essential for producing fire. • Water is commonly used to control fire. Keywords – combustion, flame, ignition • Water cannot be used to control fires involving temperature, fire extinguisher, fuel, fuel efficiency, ideal fuel, calorific value. electrical equipment or oils. • There are various types of combustions such as rapid combustion, spontaneous combustion, explosion, etc. • There are three different zones of a flame - dark zone, luminous zone and non-luminous zone. • An ideal fuel is cheap, readily available, readily combustible and easy to transport. It has high calorific value. It does not produce gases or residues that pollute the environment. • Fuels differ in their efficiency and cost. 37

6. Combustion and Flame Work Plan CONCEPT COVERAGE DETAILS PRACTICE SHEET Combustion PS-1 • Define combustion Flame • Conditions under which combustion takes PS-2 Fuel PS-3 place PS-4 • Combustible and non-combustible Self-evaluation Sheet substances • Ignition temperature • Inflammable substances • How to control fire • Structure of flame • Types of combustion • Ideal fuel • Fuel Efficiency • Calorific value • Harmful effects of increasing fuel consumption on environment Worksheet for \"Combustion and Flame\" Evaluation with self- check or peer check* 38

PRACTICE SHEET - 1 (PS-1) 1. Fill in the blanks: a. Magnesium burns to form _____________ and produces heat and light b. ________ burns in air producing carbon dioxide, heat and light. c. The substance that undergoes combustion is called_________ _______ is essential for combustion d. The substances which burn in air are called_______ e. During the process of combustion, _______ and _________ are given out f. The lowest temperature at which a substance catches fire is called its __________ 2. State whether the given statements are true or false: a. A combustible substance cannot catch fire or burn as long as its temperature is higher than its ignition temperature. b. Ignition temperature of kerosene oil is lower than that of wood. c. Inflammable substances have high ignition temperature. 3. Define combustion. 4. List any three combustible substances. 5. List any three non- combustible substances. 6. Define inflammable substances. Give examples. PRACTICE SHEET - 2 (PS-2) 1. Fill in the blanks: a. ___________ burns in air at room temperature. b. Substances which vaporise as they burn have a ________. c. A circular blackish ring formed on the glass plate that is inserted into the luminous zone of candle flame indicates deposition of ____________. d. Goldsmiths blow _____________ zone of a flame for melting gold and silver. 2. How does a fire brigade extinguish fire? 3. List the three essential requirements for producing fire? 4. What are the types of combustion? 5. Why do goldsmiths blow the outermost zone of a flame for melting gold and silver? 6. With a neat labelled diagram, show different zones of a flame. PRACTICE SHEET - 3 (PS-3) 1. What is a fuel? 2. List the qualities of a good fuel. 3. Define calorific value. 4. Why is it advised to never sleep in a room with burning or smouldering coal fire in it? 5. Fill in the blanks: a. Incomplete combustion of carbon fuels gives _________ b. The calorific value of a fuel is expressed in a unit called ___________ c. Petrol engines give off gaseous oxides of___________ d. Burning of coal and diesel releases _________ 39

PRACTICE SHEET - 4 (PS-4) 7. X and diesel are replaced by Y and LPG in automobiles. What is X and Y? I. Choose the correct option: a. X- petrol; Y- CNG 1. Increase in the percentage of carbon dioxide in b. X- paraffin; Y- petrol the air leads to: c. X- LPG; Y- diesel a. Skin cancer d. X- Hydrogen gas; Y- petrol b. Global warming 8. This is one of the major reasons that the polar c.Bilharziasis ice caps are melting. d. All a. Eutrophication 2. A substance which reacts with oxygen giving b. Soil erosion off heat is called a combustible substance. c. Deforestation Which among the following is considered as a d. Global warming combustible substance? 9. If a person's clothing catches fire, which method a. Iron rod do you think is the correct way to extinguish the b. Glass fire? c. Wood piece a. Use fire extinguisher d. Rock b. Throw water on the clothes 3. The substance that does not burn with flame c. Wrap the person with woolen blanket (among the following) is: d. Taking the person into open air a. Charcoal 10. Fires occur in forests mostly due to this reason. b. Camphor a. Overgrazing of animals c. Straw b. Heat of sun d. LPG c. Cutting of trees 4. Lowest temperature at which a substance d. Lighting strikes catches fire is called: II. Short Answer Question: a. Threshold temperature 1. What is the substance present in a fire b. Maximum temperature extinguisher? How is it able to bring fire under c. Ignition temperature control? d. Vaporizing temperature 2. Dried leaves burn easily than green leaves. Give 5. The calorific value of a fuel is expressed in: reason. a. Kilowatt/kilogram 3. In an experiment, 6.5 kg of fuel is burnt. The b. Kilojoule/kilogram heat produced was measured to be 130000 KJ. c. Kilocalorie/kilogram Calculate the calorific value? d. Dyne/gram 6. Which is a property of an ideal fuel? 40 a. Cheap and readily available b. It should have high calorific value c. It should not produce residues that pollute environment d. All the above

PRACTICE SHEET - 4 (PS-4) III. Long Answer Questions: 1. Observe the above diagram. Explain in detail. 2. Neena read in a newspaper that a person died in his sleep. He was sleeping near a laptop which was connected to a charging plug. The doctor declared him as dead and told his parents that it happened due to the release of a poisonous gas. Analyze and answer the following questions I. What might be the reason for his death? II. What are the other harmful effects of that gas? III.What are the physical properties of that gas? 41

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins 1. What is rapid combustion. Give an example.  5. Give two examples each for solid fuels and (2 Marks) liquid fuels.  (2 marks) 2. Which zone of the candle flame has the least and highest temperature? (2 Marks) 6. Fill in the blanks:  (2marks) a. The middle zone of a candle flame is also called the zone of ______ combustion. b. Increased concentration of carbon dioxide in the air is believed to cause ____________. 3. How do you extinguish fire from a person’s clothes that has caught fire?  (2 Marks) 4. Explain an experiment to show that air or oxygen is necessary for combustion.  (5 Marks) 42

7. Conservation of Plants and Animals Learning Outcomes • Explain various measures taken by the govern- ment to conserve plants and animals. At the end of this lesson, students will be able to: • Explain the importance of plant and animal • List out endemic species of various places. • List out various endangered species. resources. • Explain the importance of recycling. • Enlist causes of deforestation. • Explain various implications of deforestation on environment. Concept Map CoPnAlsaennrivtmsaatailnosdn of Deforestation Consseprevcaiteison of Recycling InChhearirtaacntceersof Wildlife Sanctuary National Park Key Points Biosphere Reserve • Deforestation means clearing of forests and using that have common characteristics and are capable of land for other purposes, i.e. for industrial set up or interbreeding among themselves to produce fertile constructing building for rehabitation. off-springs are called speices. Normally, members of a species breed amongst themselves and not with • Deforestation causes increase of atmospheric members of other species. temperature due to increase in concentration of carbon • The source book which keeps a record of all the dioxide leading to global warming. endangered animals and plants is called Red Data Books. There are different Red Data Books. • Variation refers to the differences among the • The phenomenon of movement of a species from its individuals of a species/ population. own habitat to some other for a particular time period every year for a specific purpose like breeding is known • The part of the earth in which living organisms exist or as migration. that supports life is known as biosphere. Keywords – Flora, fauna, conservation, biosphere reserve, Red Data Book, endangered • Biodiversity refers to the variety of organisms existing species, endemic species on the earth. It includes variety of plants, animals and microorganisms. • The plants found in a particular area are termed as flora of that area. The animals found in a particular area are termed as fauna of that area. • Those species of plants and animals which are found exclusively in a particular area are called endemic species to a zone, a state or a country. For example, sal and wild mango are endemic flora of the Pachmarhi Biosphere Reserve. Animals such as bison, Indian giant squirrel and fly squirrel are endemic fauna of this area. • A group of population or populations whose members 43

7. Conservation of Plants and Animals Work Plan CONCEPT COVERAGE DETAILS PRACTICE SHEET Plant resources • Deforestation PS-1 • Causes of deforestation Wildlife and conservation of • Effects of deforestation PS-2 plants and animals • Endangered species Conservation of plants and • Endemic species PS-3 animals • Wildlife sanctuary PS-4 • Biosphere reserve Self-evaluation Sheet • National park • Red data book • Recycling of materials • Reforestation Worksheet for \"Conservation of Plants and Animals\" Evaluation with self- check or peer check 44

PRACTICE SHEET - 1 (PS-1) I. Choose the most appropriate option for each of these statements: 1. Deforestation is caused due to a. grazing b. cutting trees for human use c. cultivation d. all of these 2. Most fertile layer of soil is a. top layer b. organic layer c. middle soil layer d. all of these 3. What can you do to fight deforestation? a. Plant more trees b. Reduce the usage of forest products including paper and fibre. c. Avoid frequent disposal and buying new forest products. d. All of the above 4. What are the effects of deforestation? a. More greenhouse gases b. Disturb the water cycle c. Reduced biodiversity d. All of the above II. Answer each of these questions: 1. For what purposes are the trees cut? 2. Which are the natural causes of deforestation? 3. How does deforestation affect the soil properties? 4. What is infiltration? 5. Deforestation can cause both flood as well as drought. Is this statement true? Explain your answer. PRACTICE SHEET - 2 (PS-2) I. Answer each of these questions: 1. What is biodiversity? 2. What is a biosphere reserve? 3. Which are the protected areas found in the Pachmari biosphere reserve? 4. What are endemic species? 5. Which are the endemic flora of Pachmari biosphere reserve? 6. Which are the endemic fauna of Pachmari biosphere reserve? 7. State the importance of Satpura National Park. 8. Even protected forests are not safe for flora and fauna. Justify the statement. 9. What is Project Tiger? State the purpose of Project Tiger. 10. Define the term endangered animals. 45

PRACTICE SHEET - 3 (PS-3) I. Answer each of these questions: 1. What is Red Data Book? 2. Why do birds migrate? 3. What is reforestation? 4. State the precautions to be taken while carrying out reforestation. 5. What is natural reforestation? 6. What is the aim of forest conservation act? 7. Satpura national park is an evidence of prehistoric human life in the jungles. Justify the statements. 46

PRACTICE SHEET - 4 (PS-4) 9. Deforestation leads to: a. increase in water holding capacity of soil. I. Choose the correct option: b. Decrease in greenhouse gases c. Global warming 1. Barasingha is an endangered species because: d. Storms a. It has become extinct. 10. Choose the correct options. ‘Migratory birds fly b. Its poaching is strictly prohibited. great distances’: c. They are found only in zoos and botanical i. for laying eggs gardens. ii. to avoid overcrowding d. Its population is diminishing. iii. as a ritual 2. The Red Data Book keeps a record of: iv. to protect themselves from extreme weather a. Extinct and endemic species conditions. b. Endangered animals and endangered plants a. i and ii c. Endangered plants and extinct species b. i and iii d. Endemic species and endangered animals c. i and iv 3. The finest Indian teak is found in this forest: d. i, ii and iv a. Sundarbans National park b. Satpura National Park II. Short Answer Questions: c. Corbett National park d. Kaziranga National park 1. What do you understand by the term ‘species’? 4. Which among the following does not represent a group of fauna? 2. Write two ways in which afforestation can occur. a. Bison, Indian giant squirrel, flying squirrel b. Sal, teak, mango, jamun, silver ferns, 3. There are different layers of soil. What would c. Barking deer, cheetal, leopard, wild dog, wolf, happen if the top layer of soil is exposed? d. Blue whale, tiger, leopard 5. If a clear forest area is left undisturbed, it re- III. Long Answer Questions: establishes itself. This is due to: a. Manmade reforestation 1. Write in detail about deforestation and its b. Natural reforestation causes. c. Soil Conservation d. Biodiversity 2. Save paper; Save trees!” Comment, in detail, 6. Jamun, silver ferns and teak represent: about the necessity of saving paper and write a. Species about the ways to save it. b. Fauna c. Flora d. Ecosystem 7. The production of paper: a. Does not affect forest reserves b. Saves energy c. Causes pollution d. Does not require water 8. Conservation of biodiversity in its natural habitat occurs in: a. Zoological and botanical gardens b. Botanical gardens and wildlife sanctuaries c. National parks and zoological gardens d. National parks and wildlife sanctuaries 47

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the most appropriate option for each of 2. What are the advantages of recycling paper? these statements:  (4 marks)  (3 marks) 1. The plants found in a particular area are 3. Explain the initiative taken by the government termed as: to conserve wildlife.  (5 marks) a. species b. flora c. forest d. fauna 2. The animals found in a particular area are termed as:- a. Fauna b. Species c. Flora d. Kingdom 3. A population which is capable of interbreeding is known as:- a. flora b. species c. animals d. kingdom 4. The plants, animals and microorganisms along with climate, soil river etc. of an the area is referred to as: a. fauna b. ecosystem c. species d. kingdom II. Answer each of these questions: 1. Write three characteristics of species.  (3 marks) 48

8. Cell: Structure and Functions Learning Outcomes • Describe a cell w.r.t. plasma membrane and nucleus. By the end of this chapter, you will be: • Describe about the discovery of cells. • State the functions of plasma membrane and • Define a cell as a structural and functional unit of nucleus. a cell. • Identify the parts of a plant cell and an animal • Explain cell based on its size, shape and number cell. Concept Map • Differentiate between a plant cell and an animal cell. CELLS Discovery Cell definition, Structure and Differences number, size and function between plant cells and animal shape cells Key Points • All organisms are made up of cells. • Cell is the structural and functional unit of living organisms. • Most living cells contain a nucleus, cytoplasm and cell organelles like endoplasmic reticulum, lysosomes and Golgi apparatus. • Nucleus is the master of the cell. • Plant cells can be distinguished based on the presence of a cell wall, a large central vacuole and chloroplasts. • A tissue is made up of many cells that are similar in structure and are specialized to perform a particular function. 49

8. Cell: Structure and Functions Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET PS-1 Introduction • Discovery of cell • Organisms with variety of cell shape, size and PS-2 number. PS-3 PS-4 Cell structure and function • Structure of the plant cell PS-5 • Structure of the animal cell Self-evaluation Sheet • Function of cell in the living body Parts of cell • Cell membrane • Cytoplasm • Nucleus • Plastids • Vacuole • Comparison between plant cell and animal cell Worksheet for “Cell: Structure and Functions” Evaluation with self- check or Peer check* 50

PRACTICE SHEET - 1 (PS-1) I. Pick the appropriate term for each of the following descriptions: 1. Structural and functional unit of an organism. 2. The organelle that controls the activities of the cell. 3. Green coloured plastid found in plant cells. 4. Coloured bodies seen in a cell. 5. Thread like bodies inside the nucleus. 6. Jelly like living material inside a cell. 7. A part found in plant cell outer to plasma membrane. 8. Blank looking structures that may be big in plant cells and small in animal cells. 9. Cells having nuclear material without a nuclear membrane. 10. Cells having well-organized nucleus with a nuclear membrane. II. Say True or False: 1. A cell is a structural and functional unit of a cell. 2. Multicellular animals have many cells. 3. Plastids occur in animals because they are colourful. 4. Animal cells have large vacuole. 5. Golgi bodies, mitochondria, ribosomes occur in cytoplasm. PRACTICE SHEET - 2 (PS-2) I. Label the parts of the animal cell and animal cell. II. Comparing a plant cell and an animal cell, complete the table. PART ANIMAL CELL PLANT CELL Cell membrane Present Present Cell wall Present Nucleus Present Present Nuclear membrane Cytoplasm Present Present Plastids Vacuole 51

PRACTICE SHEET - 3 (PS-3) 8. Choose the correct statement: a. Genes are located in the chromosomes. I. Choose the correct option: b. Cell is located in the nucleus. 1. Choose the correct statement with respect to c. Chromosomes are located in the nucleolus. unicellular organisms: d. Cell membrane surrounds the nucleus. a. In unicellular organisms, tissues work in co- ordination to perform different functions. 9. Green colour of leaves is due to presence of b. Unicellular organisms do not require food. the pigment_____ c. Unicellular organisms respire and a. Chlorophyll reproduce. b. Mitochondria d. All unicellular organisms move by cilia. c. Ribosomes 2. Majority of cells cannot be seen directly with d. Chloroplast our naked eyes because: a. Organisms are generally unicellular 10. The unit of measurement used for expressing b. Cells are microscopic dimension (size) of cells is: c. Cells are present only inside the body a. Centimeter d. Cells are grouped into tissues b. Micrometer 3. Read the different combinations of terms c. Millimeter given below: d. Metre a. Cell wall, cell membrane, nucleus, plastid b. Cell wall, nucleus, ribosome, chromosome 11. The most important function of cell c. Cell membrane, mitochondria, ribosome, membrane is that it: chromosome a. Controls the entry and exit of materials d. Cell membrane, ribosome, mitochondria, from cells. chloroplast. b. Controls only the entry of materials into The correct combination of terms with cells. reference to an animal cell is _____. c. Controls only the exit of materials from 4. Which one of the following term is not a part cells. of the nucleus? d. Allows entry and exit of materials without a. Ribosome any control. b. Chromosome c. Nucleolus 12. Paheli accidentally placed her hand over a d. Gene flame and immediately pulled it back. She 5. A suitable term for the various components felt the sensation of heat and reacted due to of cells is the action of a. Tissue a. Blood cells b. Chromosomes b. Nerve cells c. Cell organelles c. Skin surface d. Genes d. Nucleus of cells 6. The jelly-like fluid substance present in cells is called a. Protoplasm b. Chloroplast c. Chromosome d. Cytoplasm 7. Read the following terms and select the pair that is related to inheritance of characters. a. Cell wall and cell membrane b. Chromosome and mitochondria c. Chloroplast and cell membrane d. Chromosome and genes 52

PRACTICE SHEET - 4 (PS-4) I. Answer the following: 1. In leaves, name the cell organelle and pigment that is responsible for green colour. 2. The instrument used to observe cells is ________ 3. Observe the following diagram given. Answer the following questions. a. Does it represent a plant cell or an animal cell? b. Does it represent a prokaryotic cell or an eukaryotic cell? 4. Read the following statements and write the appropriate term against each statement. a. I control the functions of a cell. Who am I? b. I am like a policeman. I do not allow anything and everything to get in and out of the cell. Who am I? c. I transfer characters from parents to offsprings. Who am I? 5. Cells consist of many organelles, yet we do not call any of these organelles as structural and functional unit of living organisms. Explain. 6. The size of the cells of an organism has no relation with the size of its body. Do you agree? Give reason for your answer. 53

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option: 9. The unit that helps in transfer ofcharacteristics 1. These are the building block of life. from the parent to the offspring is the: a. Proteins a. Cell b. Cells b. Nucleus c. Tissues c. Gene d. Gene d. Chromosome 2. Energy production in a cell occurs in the: 10. Which of the following cells can get into a. Nucleus intercellular spaces to fight germs? b. Protoplasm a. Red blood cells c. Vacuoles b. Nerve cells d. Mitochondria c. White blood cells 3. This unicellular organism does not have a d. Bone cells definite shape. II. Short Answer Questions: a. Paramoecium 1. Draw a neat, labelled diagram of the cell that b. Euglena receives and transfers messages. c. Amoeba 2. Why is a cell wall present in plant cells? d. Bacteria 3. Ria did not know about the function of empty 4. The egg of a hen is made up of: organelles in the cell. Which organelle is a. Multiple cells Ria thinking about? What could be the b. Two cells importance of such structures? c. One cells III. Long Answer Questions: d. No cell 1. The shape and size of the cells vary among 5. The empty structures in a cell are: organisms and within the organism too a. Endoplasmic reticulum Comment. b. Cell membrane 2. Draw a neat labelled diagram and explain the c. Vacuoles ‘control center of a cell’ in detail. d. Mitochondria 6. Chromosomes are visible only: 54 a. Through compound microscope b. When the cell is at rest c. When the cell is dividing d. When both when cell is at rest and while dividing. 7. The exchange of materials between cytoplasm and the nucleus occurs through: a. Endoplasmic reticulum b. Cell membrane c. Nuclear membrane d. Golgi complex 8. Choose the incorrect statement. a. All cells arise from pre-existing cells. b. In unicellular organisms, a single cell performs all the body functions. c. All microorganisms are multicellular. d. Bacteria and Amoeba are unicellular.

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Draw a neatly labelled diagram of a plant cell 4. Write any one importance of cell wall. and label any four of its parts: (5 Marks) 5. Name the living substance of the cell. II. Fill In The Blanks: (3 Marks) 6. Of the following parts of a cell listed below, name the part that is common to plant cell, The outermost layer of plant cells is the animal cell and a bacterial cell. (a)________ beneath which is the (b)______. a. Chloroplast The term (c)________ refers to the jelly-like b. Cell membrane substance containing all the (d) _____________. c. Cell wall The (e)____________ contains thread-like d. Nucleus Structures called (f) ______________ 7. The thread-like structures present in the III. Answer the questions: (7 Marks) nucleus are 1. How does paramecium move? a. Nucleolus b. Genes c. Chromosomes d. Ribosomes 2. What is the function of a nerve cell? 3. Define tissues. 55

9. Reproduction in Animals Learning Outcomes At the end of this lesson, students will be able to: • Explain the process of fertilization. • State the importance of reproduction. • Explain the process of embryo formation. • State different modes of reproduction. • Differentiate between internal and external • Explain the structure and function of different fertilization. parts of human reproductive system. • Explain the process of metamorphosis. • Differentiate between oviparous and viviparous • Describe budding and fission as types of asexual animals. reproduction. Concept Map Reproduction in animals Sexual Asexual reproduction reproduction External Internal Fission Budding fertilization fertilization Key Points • The stage when cells produced hp, the division of the zygote begin to form groups that develop into • The process of reproduction is not essential for the different tissues and organs of the body which is survival of an individual but reproduction is essential termed as an embryo. for the continuation of a species. • The stage of an embryo in which all the body parts • Modes of reproduction: Like plants, animals also can be identified is known as foetus. reproduce by (i) Sexual reproduction and (ii) Asexual reproduction. • The animals such as dog, lion, elephant, cat etc., which give birth to young ones are called • The type of reproduction beginning from the viviparous. fusion of male and female gametes is known as sexual reproduction. • The animals, such as lizards, butterfly, crow and hen, which lay eggs that hatch and give rise to • In this process of sexual reproduction, a male and young ones are called oviparous. a female gamete (reproductive cells) fuse to form a single cell called zygote. • Sexually reproducing animals start their life from a zygote which develops into an embryo that grows • This zygote gradually develops into an adult, into mature adult. The adult produces sex cells similar to the parents. (egg and sperm). The fusion of sperm and egg leads to zygote. This whole cyclic order is known • The type of reproduction in which only a single as life-cycle. parent is involved is called asexual reproduction. Keywords – reproduction, metamorphosis, • Male human reproductive organs contain a pair oviparous, viviparous, sperm, ova, sperm, testes, of testes (singular-testis), two sperm duct and a zygote, embryo. penis. • Female human reproductive organs contain a pair of ovaries which produce female gametes called ova (eggs). 56

9. Reproduction in Animals Work Plan CONCEPT COVERAGE DETAILS PRACTICE SHEET Male reproductive system PS-1 Sexual reproduction in human be- • Female reproductive system ings • Fertilisation PS-2 Embryo formation • Internal fertilisation PS-3 • External fertilisation PS-4 Oviparous animals Self-evaluation Sheet Sexual reproduction in animals • Viviparous animals • Metamorphosis • Fission • Budding • Cloning Asexual reproduction • • • Worksheet for \"Reproduction in Animals\" Evaluation with self- check or peer check 57

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks: 1. The testes produce the male gametes called _____. 2. The female gametes are called _____. 3. ______ is the part where development of the baby takes place. 4. The fusion of the egg and the sperm is called _______. 5. The stage of the embryo in which all the body parts can be identified is called a _____. II. Answer each of these questions: 1. List the organs of male reproductive system. 2. List the organs of female reproductive organs. 3. Define fertilization. 4. How is a zygote formed? 5. In what way are external fertilization and internal fertilization different? Explain with examples. 6. Draw a neat labelled diagram showing the fertilisation. PRACTICE SHEET - 2 (PS-2) I. Answer each of these questions: 1. How does fertilization occur in frogs? 2. In what way are oviparous animals different from viviparous animals? 3. What is metamorphosis? 4. How does fertilization occur in hen? 5. How are eggs of frogs protected? PRACTICE SHEET - 3 (PS-3) I. Answer each of these questions: 1. Write the difference between sexual and asexual reproduction? 2. How does amoeba reproduce? 3. Draw a diagram to show budding in yeast. 4. What is cloning? 5. Draw a neat, labelled diagram showing the reproduction in amoeba. 58

PRACTICE SHEET - 4 (PS-4) I. Choose the correct option: 7. Ajay observed a slide of budding in hydra under a 1. The organism that undergoes internal microscope. Which of these following observations fertilisation and is oviparous is: made by him is correct? a. Frog b. Cow a. The buds of hydra are larger than the parent c. Butterfly d. Hen b. The buds of hydra are smaller than the parent 2. Choose the method of fertilisation used by a starfish. c. A cluster of buds are seen at the same point a. In-vitro fertilisation b. Internal fertilisation d. Buds are seen all over the body of hydra c. External fertilisation d. No fertilisation 8. Which of the following statements about human 3. A sperm is made up of: reproduction is correct? a. Two cells b. One cell a. The female gametes are produced throughout c. Four cells their lifetime. d. Many cells 4. How many nuclei does a zygote formed by fusion b. The male gamete is smaller than the female of a single nucleated ovum and a single nucleated gamete. sperm have? a. Two nuclei c. The production of male gametes is less than the b. Four nuclei production of female gametes. c. One nucleus d. No nucleus d. Female gametes are motile. 5. Which of the following results in the maintenance of parental identity? 9. The picture given below depicts reproduction a. Budding stage in hydra. Which of the following organisms b. Binary fission can reproduce the same way? c. Asexual reproduction d. All the above a. Yeast 6. The young ones that are produced as a result of asexual reproduction are. b. Amoeba a. Non identical to the parent b. Identical to the parent c. Paramecium c. Non identical daughter cells d. Identical to individuals from other parents d. All the above 10. Read the following two statements in which one of them is an assertion (A) and the other is a reason (R). Assertion: Amoeba reproduces by fission. Reason: All unicellular organisms undergo asexual mode of reproduction. Identify the correct response. A. A is true, and R is false B. A is false, and R is true C. Both A and R are false D. Both A and R are true II. Short Answer Questions: 1. Can animals produce offspring even without the formation of zygotes? If so, how? Explain with a suitable example. 2. Neha found a tadpole in a pond. Shecarefully collected it and put it in an aquarium thinking it was a fish. After some days, what do you think did she’ll find? 59

PRACTICE SHEET - 4 (PS-4) 3. Solve the jumbled words: i. EHPHRITEODMA ii. AGMIST iii. IONTFERTILIZA iv. YZTOGE v. GNINOLC vi.ISXUAELB III. Long Answer Questions: 1. Explain the process by which Dolly the sheep was formed. 2. a) Is metamorphosis a word used for human development? Explain. b) Give two examples of animals that undergo metamorphosis. c) What would happen if all animals stop giving birth to their babies? 3. Draw a diagram to show fertilisation in humans. Define fertilisation and its types. Give examples of each. 60

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the most appropriate option for each of 2. Draw a neat labelled diagram of a female these statements:  (4 marks) reproductive system. Which organ produces ova?  (3 marks) 1. The cell formed after fertilization is called: a. Gamete b. Zygote c. Embryo d. None of these 2. Foetus is the: a. Well developed embryo b. Developing embryo c. A zygote d. Male gamete 3. Viviparous organisms are the ones which: a. Produce eggs b. Produce young ones c. Both a and b d. None of these 4. Cloning is a mode of: 3. How does development of embryo take place?  (5 marks) a. Sexual production b. Asexual production c. Both a and b d. None of these II. Answer each of these questions. 1. In which organ are the sperms produced? Draw a neat labelled diagram of a human sperm.  (3 marks) 61

10. Reaching the Age of Adolescence Learning Outcomes At the end of this lesson, students will be able to: • Describe the importance of personal hygiene. • List out the body changes seen during puberty. • Describe the importance of balanced diet. • Differentiate between primary and secondary sexual characters. • Explain the menstrual cycle in females. • Explain the role of various hormones in the hu- man body. Concept Map Reaching The Age of Adolescene Puberty RepProhdausective HHuamrmaonnBeosdiny Key Points • The first menstrual flow which begins at puberty is known as menarche. • The period of life, when the body undergoes changes, leading to reproductive maturity is • Menopause happens between 45 and 50 years of known as adolescence. age, the menstruation cycle stops. Stoppage of menstruation is known as menopause. • Generally, adolescence begins at the age of 11 and lasts upto 18 or 19 years of age. Adolescents • Adolescence has periods of confusion or insecurity. are also called teenagers because they cover the Some people take advantage of this and lead period of the 13 to 18 or 19 years of age. adolescents to bad habits. They are addictive, and sexual contact with people might happen. • Puberty is the period of adolescence during which an adolescent reaches sexual maturity and Keywords – hormones, menarche, menopause, becomes able to have children. adolescence, menstruation, insulin, thyroxine. • Secondary sexual characters are development of breasts in girls, growth of moustaches and beard in boys. • Hormones control the changes that occur at adolescence. The male hormone called testosterone is secreted by the testes at the onset of puberty and cause development of facial hair, chest hair etc. At the onset of puberty in girls, ovaries secrete female hormone or estrogen which makes the breast develop. Their secretion is under the control of pituitary endocrine gland. 62

10. Reaching the Age of Adolescence Work Plan CONCEPT COVERAGE DETAILS PRACTICE SHEET Adolescence and puberty • Puberty PS-1 • Primary and secondary sexual characters Role of hormones and • Role of hormones PS-2 reproductive phase • Menstrual cycle • Pregnancy PS-3 • Sex determination Self-evaluation Sheet • Reproductive health Worksheet for \"Reaching the Age of Adolescence\" Evaluation with self- check or peer check 63

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks: 1. _____ ends when an adolescent reaches reproductive maturity. 2. The voice box is also known as _____. 3. _____is the female hormone. II. Answer each of these questions: 1. What is adolescence? 2. Reema is a 13 year old girl. Though Reema has grown taller, her face looks much smaller compared to her body. Is this an abnormality? Explain your answer. 3. The height of an individual is more or less similar to that of some family member. Justify the statement. 4. What is Adam’s apple? 5. Ram is a 14 year old boy. Since a past few months he is noticing many pimples on his face. What could be the reason for this? 6. Which hormones are secreted by the pituitary gland? 7. Why are endocrine glands called as ductless glands? 8. How does sex organs in males and females develop at the age of puberty? PRACTICE SHEET - 2 (PS-2) I. Fill in the blanks: 1. The first menstrual flow begins at puberty and is termed _____. 2. Stoppage of menstruation is termed ______. 3. All human beings have ___ pairs of chromosomes in the nuclei of their cells. 4. Two chromosomes out of these are the sex chromosomes, named __ and ___. 5. The hormone produced by thyroid gland is ____. 6. Diabetes is caused due to the deficiency of ____ hormone. 7. Metamorphosis in insects is controlled by ____ hormones. II. Answer each of these questions: 1. What is a target site? 2. What is the reproductive span in human females? 3. State the importance of personal hygiene for teenagers. 4. How does HIV and AIDS spread? 64

PRACTICE SHEET - 3 (PS-3) I. Choose the correct option: 9. In females, the uterine wall thickens to receive the: 1. The period when a person is a teenager is: a. Gamete a. 5 to 10 years b. Zygote b. 10 to 15 years c. Embryo c. 13 to 19 years d. Fetus d. 15 to 20 years 10. The formation of a male child occurs when: 2. Endocrine glands are also known as: a. X chromosome from a female meets X chromosome a. Sebaceous glands from a male. b. Sweat glands b. Y chromosome from a female meets X chromosome c. Hormones from a male. d. Ductless glands c. X chromosome from a female meets Y chromosome 3. Which among the following cause AIDS? from a male. a. Bacteria d. Y chromosome from a female meets Y chromosome b. Fungi from a male. c. Virus d. Amoeba II. Short Answer Questions: 4. Which among the following is not true about adolescence? 1. Define menstruation. Write the terms used when a. An adolescent is neither a child nor an adult. the cycle first starts and when it stops for the last b. Adolescence may begin earlier in girls than in boys. time. c. It does not vary from person to person, but it is fixed. 2. Draw a neat labelled diagram to show sex d. It marks the onset of puberty. determination in humans. 5. The release of sex hormones are controlled by: a. Sebaceous glands 3. Given below are the jumbled names of glands b. Pituitary glands and its related hormones. List the endocrine glands c. Testes among them and pair them correctly with the d. Ovaries hormones they release. 6. Including green leafy vegetables and jaggery in a diet reduces the risk of: Thyroid, Ovary, Testes, Insulin, Growth hormone, a. Diabetes Adrenal, Pituitary, Oestrogen, Testosterone, b. Thyroid Pancreas, Thyroxine, Adrenaline c. Anemia d. Goitre III. Long Answer Questions: 7. The deficiency of this nutrient results in goitre in humans. 1. What are the changes that occur in a teenager’s a. Iron body during puberty? b. Copper c. Sodium 2. The parents of Radha and Rajesh decided to get d. Iodine them married. Rajesh is 21 years old and Radha’sis 8. Nia’s car almost collided with a huge truck. 16 years old. Is the parents’ decision correct? Justify However, she escaped safely. Which hormone you answer. predominantly would have been released to recover from the situation? a. Thyroid b. Insulin c. Adrenalin d. Estrogen 65

SELF-EVALUATION SHEET Marks: 15 Time: 30 Mins I. Answer each of these questions: 4. The belief that the mother is responsible for the sex of her baby is completely wrong. 1. Why does the voice of adolescent boys become Justify this statement.  (3 marks) hoarse?  (1 mark) 2. Explain how hormones control the process of metamorphosis in frogs.  (3 marks) 5. Explain menstrual cycle in human females.  (5 marks) 3. Doctor noticed a bulge is Suresh’s throat. Identify the disease, cause of the disease and a remedy to cure the disease.  (3 marks) 66

11. Force and Pressure Learning Outcomes • Explain types of contact forces. • Explain the types of non contact forces. By the end of this chapter, you will be: • Define pressure. • Define force • State the formula and units to calculate • Explain the effects of forces on a body. • Cites examples from day to day life for different pressure. • Compute problems based on the formula effects of forces on the body. • Classify forces as contact and non contact forces. Pressure=Force/Area of cross section. • Explain air pressure and liquid pressure. Concept Map FORCE AND PRESSURE Force Pressure Definition Effect of Types of Calculation Types force forces and SI units Moves an Speed Changes Changes Contact Non contact force object of a direction shape force of the from rest moving of object Muscular Frictional Magnetic Electrostatic Gravitational object motion force force force force force Key Points • The distance travelled by an object and the speed with which it travels, depends on the amount of • Push and pull are forces that move things. force applied on it. • Force can change the speed and direction of a • When force acting on an object is in contact with moving object. the object, it is known as contact force. Push and • Force can change the shape of the object. pull are contact forces. • When equal and opposite forces act on an object, • Forces which act without coming in contact the object remains stationary. with the object, is known as non contact forces. • When forces are applied in the same direction on Magnetic and gravitational forces are non contact forces. the object, the sum of the forces act on the object. • When the forces are applied on the object in the • Solids, liquids and gases exert pressure. • SI unit of measuring force is Newton (N) and opposite direction, the difference between the forces act on the object. pressure is Pascal. (Pa) • Atmospheric pressure is maximum at the sea level. It decreases with height. 67

11. Force and Pressure Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEET SIMULATION/VIDEO Force - A pull or push • Examples of force in daily life Contact Forces Forces due to an situations Force Changing The interaction State of Motion Exploring forces • Pull and Push Pressure Exerted by Effects of force • Condition required to exert force PS-1 Liquids • Magnitude of force Non-Contact Forces • Direction of force Pressure • Change in state of motion • Change in shape of the object Contact forces • Muscular force PS-2 Non-contact force • Example of muscular force in daily life • Friction • Condition required to exert frictional force • Example of friction in daily life • Magnetic force • Electrostatic force • Gravitational force Pressure • Pressure PS-3 • Relation between force, area and pressure • Daily life examples of pressure • Pressure exerted by liquids and gases Atmospheric pressure • Atmosphere PS-4 • Atmospheric pressure • Pressure inside the body of living beings Worksheet for “Force and Pressure” PS-5 Evaluation with self- Self-evaluation check or Peer check* Sheet 68

PRACTICE SHEET - 1 (PS-1) I. Say True or False: 1. Force changes the speed of the moving object. 2. Distance travelled by an object does not depend on the amount of force applied on it. 3. Muscular force is a non contact force. 4. Pressure is the result of force exerted over an area. 5. Push is a contact force and pull is a non contact force. II. Fill in the Blanks: 1. The ratio between the ________ and __________ is called pressure. 2. When a force of one ________ acts on an area of cross section 1m2, the pressure exerted is said to be __________. 3. ___________ force can pull some objects of iron. 4. Gravitational force is always _____________ in nature. 5. The SI unit of pressure is ______________. 6. Lubricants are used in machine to __________ friction. 7. Muscular force is an example of ___________ force. 8. Force can change the ____________ of motion of an object. 9. The force which opposes the motion is called ___________. 10. If the area of contact is increased, then pressure ______________. PRACTICE SHEET - 2 (PS-2) I. Solve the following problems: Remember the formula Pressure=Force/Area. 1. Sheela wants to lift a heavy box. The force of gravity pulls it downwards with 500N. a. How much force will Sheela apply to lift the box? b. If Suresh supports the box from below with a force of 250N, how much force will Sheela have to apply to lift the box? 2. A force of 5000N acts on an area of 5m2. Find the pressure in pascal. 3. Calculate the area of the body which experiences a pressure of 60,000Pa by a force of 120N. II. Choose the Odd One Out with Proper Reasoning: 1. Push, pull, pressure 2. Lifting a bucket, a worker pulling a cart, leaf falling from a tree, a batsman hitting a cricket ball. 3. Using ball bearings, polishing the surfaces, using lubricants, grooves in tyres. 4. Muscular force, mechanical force, gravitational force, frictional force. III. Match the Following: COLUMN A COLUMN B 1. Mechanical force A. Moon revolves round the earth. 2. Muscular force B. Crane is used to lift a heavy load. 3. Gravitational force C. Piece of paper sticks to comb after brushing the comb on the hair. 4. Frictional force D. A man walks on a levelled road. 5. Electrostatic force E. A man lifts a heavy box 69

PRACTICE SHEET - 3 (PS-3) 8. In Fig, two boys A and B are shown applying force on a block. If the block moves towards I. Choose the Correct Option: the right, which one of the following 1. The SI unit of force is: statements is correct? a. joule b. Kg/m2 a. Magnitude of force applied by A is greater c. newton than that of B. d. pascal 2. A box of weight 400N is kept on the floor. The b. Magnitude of force applied by A is smaller area of contact is 4m2. The pressure exerted than that of B. by the box on the floor is: a. 100Pa c. Net force on the block is towards A. b. 200Pa d. Magnitude of force applied by A is equal to c. 300 Pa d. 400 Pa that of B. 3. A cricketer catches a ball. The force coming 9. In the circuit shown in, when the circuit is into action is: a. Contact force completed, the hammer strikes the gong. b. Gravitational force Which of the following force is responsible c. Frictional force for the movement of hammer? d. All of these. 4. Force has: a. Only magnitude a. Gravitational force alone b. Only direction b. Magnetic force alone c. Both magnitude and direction c. Electrostatic force alone d. Neither magnitude nor direction. d. Frictional force alone 5. When meteors burn in an atmosphere, it is due to: 10. During the dry weather, while combing hair, a. Electrostatic force sometimes we experience hair standing up. b. Magnetic force The force responsible for this is: c. Frictional force a. Force of gravity. d. Gravitational force b. Force of friction. 6. An apple falling from a tree is an example of: c. Electrostatic force. a. Frictional force d. Magnetic force. b. Magnetic force c. Gravitational force d. Electrostatic force 7. Magnetic forces causes: a. Attraction only b. Repulsion only c. Both attraction and repulsion d. None of these. 70

PRACTICE SHEET - 3 (PS-3) 15. A brick is kept in three different ways on a table as shown in Fig. The pressure exerted 11. Fig shows a container filled with water. by the brick on the table will be: Which of the following statements is correct about pressure of water? a. Maximum in position A a. Pressure at A> Pressure at B> Pressure at C b. Maximum in position C b. Pressure at A=Pressure at B=Pressure at C c. Maximum in position B c. Pressure at A< Pressure at B>Pressure at C d. Equal in all cases. d. Pressure at A< Pressure at B<Pressure at C 12. Two objects repel each other. This repulsion could be due to: a. Frictional force only b. Electrostatic force only c. Magnetic force only d. Either a magnetic or an electrostatic force 13. Which one of the following forces is a contact force? a. Force of gravity b. Magnetic force c. Force of friction d. Electrostatic force 14. A water tank has four taps fixed at points A, B, C, D as shown in Fig. The water will flow out at the same pressure from taps at: a. B and C b. C and D c. A and B d. A and C 71

PRACTICE SHEET - 4 (PS-4) I. Answer the Following: 1. A ball of dough is rolled into a flat chapatti. Name the force exerted to change the shape of the dough. 2. Where do we apply a force while walking? 3. While sieving grains, small pieces fall down. Which force pulls them down? 4. Does force of gravity act on dust particles? 5. Two persons are applying forces on two opposite sides of a moving cart. The cart still moves with the same speed in the same direction. What do you infer about the magnitudes and direction of the forces applied. 6. Two thermocol balls held close to each other move away from each other. When they are released, name the force which might be responsible for this phenomenon. Explain. 7. Fruits detached from a tree fall down due to force of gravity. We know that a force arises due to interaction between two objects. Name the objects interacting in this case. 8. It is difficult to cut cloth using a pair of scissors with blunt blades. Explain. 9. Two women are of the same weight. One wears sandals with pointed heels while the other wears sandals with flat soles. Which one would feel more comfortable while walking on a sandy beach? Give reasons for your answer. 10. Volume of water taken in each vessel is as shown. Arrange them in the order of decreasing pressure at the base of each vessel. Explain. 72

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option: 9. Observe the situations and choose the correct 1. The formula for calculating pressure is: type of force acting on both. a. Work/ area b. Force/ area I. Donkey carrying a heavy load. c. Power/ time II. Car coming to rest when engine is switched off. d. Mass/time a. I- mechanical force;II- gravitational force 2. The force responsible for changing the state of b. I- Frictional force ; II- Mechanical force motion of objects is: c. I- magnetic force ; II - frictional force a. Gravitational force d. I- muscular force ; II- frictional force b. Mechanical force 10. c. Frictional force d. Magnetic force Two boys A and B, are applying force on a 3. This is an example of contact force. block in opposite directions. If the block a. Frictional force moves towards right, which of the following b. Magnetic force statements is correct? c. Electrostatic force a. Magnitude of force applied by A is smaller than d. All the above force applied by B. 4. Force can be measured by its: b. Magnitude of force applied by A is greater than a. State of position force applied by B b. State of motion c. Magnitude of force applied by A and B are c. Magnitude equal. d. Speed d. Net force applied on the block is towards A. 5. The motion of an object occurs due to: a. Action of gravity II. Short Answer Question: b. Action of force 1. Observe the picture given here. Imagine a c. Action of weight container filled with water. d. Action of pressure 6. This is a common force exerted by all the objects Answer the following questions by looking at the in the universe. picture. a. Magnetic force a. Do liquids exert pressure? b. Frictional force b. At which point is maximum and minimum c. Gravitational force d. Mechanical force pressure is observed? 7. Rama was combing his hair and he noticed it c. Give an example where you can show liquid was rising up. The weather was dry on that day. Which force is responsible for the hair to rise up? exerts pressure. a. Frictional force 2. Calculate the pressure produced by a force of b. Electrostatic force c. Magnetic force 800 N acting on an area of 2.0 m2. d. Muscular force 8. Which among the following is used as one of the measures for forecasting weather? a. Pressure exerted by water b. Pressure exerted by air c. Pressure exerted by heat d. Pressure exerted by cyclones 73

PRACTICE SHEET - 5(PS-5) 3. Saima tossed a coin and it hit the ground with a certain force. a. What is the position of the coin when it was in Saima’ s hand? b. Which force is responsible for the coin to reach the ground? c. What kind of force is this? (attractive/ repulsive) III. Long Answer Questions: 1. Define different types of forces. 2. An archer shoots an arrow applying X force. However, after moving some distance it falls due to force Y. Guess X and Y force and explain them briefly. 74

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Fill in the Blanks:  (3 Marks) IV. Answer the Following:  (6 Marks) 1. The broad tyres of a tractor _____________ 1. Name two effects a force can have on a pressure on the soft ground. moving body. 2. With increase in force, the magnitude of pressure on a given area __________. 3. The force of ______ always attracts objects towards the earth. II. Solve the Following:  (3 Marks) 1. A brick weighing 20N and having dimensions 25cm x10cm x 5cm is kept on the ground in three different ways. Calculate its pressure in three cases. 2. Define pressure. What are the SI units of force and pressure. III. Give reasons for the following:  (3x1=3) 1. Base of taller buildings are made broader. 2. Oil is applied to moving parts of a machine. 3. Your feet hurts when you have walked a long distance wearing a pencil heeled footwear. 75

12. Friction Learning Outcomes • Describe ways to increase or decrease friction. • Explain fluid friction. By the end of this chapter, you will be: • Relate the streamlined body of birds/aeroplane / • Identify friction as an opposing force to motion. • Explain the factors affecting friction. fish reduce friction. • Substantiate friction is a necessary evil. Concept Map FRICTION Factors Advantages and Types of friction Increasing and affecting disadvantage of decreasing friction friction friction Key Points • Friction is a force that results when two surfaces rub against each other. • Friction acts in the opposite direction of the motion and slows down a moving object. • A rough surface increases friction whereas a smooth surface reduces friction. • When an object slides, it gives rise to sliding friction. • When an object rolls, it gives rise to rolling friction. • When an object is at rest, it encounters static friction. It resists motion. • Friction is essential for an object to move on a solid surface. • Ball bearings and lubricants help to reduce friction. 76

12. Friction Work Plan CONCEPT COVERAGE COVERAGE DETAILS PRACTICE SHEETS SIMULATION/ VIDEO Force of friction • Concept of friction PS-1 Effect of surface on Factors affecting friction • Factors that affects friction Friction: Activity 12.2 and • Uses of friction in daily lives Effect of surface on Advantages of friction PS-2 Friction: Activity 12.3 Methods to Reduce Friction • Ways to increase and reduce Increasing and reduction friction PS-3 friction and Fluid friction • Fluid friction PS-4 • Examples of shapes that overcome fluid friction Worksheet for “Friction” PS-5 Self-evaluation Evaluation with self- Sheet check or Peer check* 77

PRACTICE SHEET - 1 (PS-1) I. Say True or False: 1. Friction is generated when two surfaces rub against each other. 2. A rough surface decreases friction. 3. Every object at rest possesses static friction. 4. An object sliding over a surface encounters less friction. 5. Grease acts like a lubricant to reduce friction. II. Fill in the blanks: 1. _________ opposes relative motion between the surface of the book and the slide. 2. The force of friction is always ____________ to the applied force. 3. _____________ is a device used for measuring the force acting on an object. 4. Friction can produce ____________. III. Match the terms with the definitions: TERM DEFINITION ANSWER 1. Friction Friction offered by an object to resist motion 2. Rough surface Friction generated due to speed of an object that moves in a fluid. 3. Smooth surface 4. Static friction Substance that helps to reduce friction 5. Fluid friction Surface with less irregularities Force that results when two surfaces rub against each other. 6. Drag Friction offered by liquids and gases 7. Lubricant Surface with more irregularities PRACTICE SHEET - 2 (PS-2) I. Statements given below are incorrect. Write correct statements: 1. When we walk on the ground, friction acts along the direction of motion. 2. Air offers no friction. 3. Rolling friction is greater than sliding friction. 4. Rubbing both hands to create heat is an example of static friction. 5. A rough surface has less irregularities. II. Classify the following examples into different kinds of friction: 1. A sled sliding across snow or ice. 2. A book on the table 3. Truck tyre 4. A car standing at traffic lights. 5. Carrying a suitcase with wheels. 6. Rope and pulley to draw water from the well. 7. A photograph in a photo frame. 8. A blackboard hanging on the wall. 9. A washing machine pulled along the floor. 10. Bike wheels. 11. A book on the shelf. 12. Vegetable tray against the holder in the refrigerator. 78

PRACTICE SHEET - 3 (PS-3) I. Choose the correct option: a. From right to left (←) b. Vertically downwards (↓) 1. Rockets have a special streamlined body c. From left to right(→) in order to: d. Vertically upwards (↑) 10. To sharpen the blade of a knife by rubbing it a. Increase friction against a surface, which of the following will b. Reduce friction be most suitable? c. Make them attractive a. Stone d. None of these. b. wooden block c. plastic block 2. A wheel is made circular because: d. glass block 11. A toy car released with the same initial speed a. It minimizes friction will travel farthest on: b. It increases friction a. Muddy surface c. To make them attractive b. Cemented surface d. None of these. c. Polished marble surface d. Brick surface 3. A dolphin swimming in the sea experiences: 12. If we apply oil on door hinges, the friction will: a. Increase a. Fluid friction b. Disappear altogether b. Sliding friction c. Decrease c. Static friction d. Will remain unchanged d. Rolling friction 13. Which of the following statements is incorrect? a. Friction acts on a ball rolling along the 4. The surface on which a toy car pushed with the same force travels the farthest is: ground. b. Friction acts on a boat moving on water. a. Bed sheet c. Friction acts on a bicycle moving on a smooth b. Glass c. Grass road. d. Paper d. Friction does not act on a ball moving 5. Applying grease on the hinges of the door: through air. 14. A boy rolls a rubber ball on a wooden surface. a. Increases friction b. Reduces friction The ball travels a short distance before coming c. Keeps friction constant to rest. To make the same ball travel longer d. Increases the weight. distance, before coming to rest, he may: a. Spread a carpet on the wooden surface. 6. A smooth surface offers: b. Cover the ball with a piece of cloth. c. Sprinkle talcum powder on the wooden a. No friction b.  Less friction c. More friction d.  More heat. surface. 7. Frictional force exerted by liquids is called: d. Sprinkle sand on the wooden surface. 15. In a large commercial complex, there are a. Motion b.  Pressure four ways to reach the main road. One of the c. Drag d. Lubricant path has loose soil, the second is laid with 8. Whenever the surfaces in contact tend to polished marble, the third is laid with bricks move or move with respect to each other, the and the fourth has gravel surface. It is raining force of friction comes into play: heavily and Paheli wishes to reach the main road. The path on which she is least likely to a. Only if the objects are solid. slip is: b. Only if one of the two objects is liquid. a. Loose soil. c. Only if one of the two objects is gaseous. b. Bricks. d. Irrespective of whether the objects are c. Polished marble. d. Gravel. solid, liquid or gaseous. 79 9. In Fig, a boy is shown pushing the box from right to left. The force of friction will act on the box:

PRACTICE SHEET - 4 (PS-4) I. Answer the following: 1. Two blocks of iron of different masses are kept on a cemented floor as shown in Fig.. Which one of them would require a larger force to move it from the rest position? 2. Will force of friction come into play when a rain drop rolls down a glass window pane? 3. Two boys are riding their bicycles on the same concrete road. One has new tyres on his bicycle while the other has tyres that are old and used. Which of them is more likely to skid while moving through a patch of the road which has lubricating oil spilled over it? 4. Is there a force of friction between the wheels of a moving train and iron rails? If yes, name the type of friction. If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction? 5. While playing tug of war, Preeti felt that the rope was slipping through her hands. Suggest a way out for her to prevent this. 6. A marble is allowed to roll down an inclined plane from a fixed height. At the foot of the inclined plane, it moves on a horizontal surface (a) covered with silk cloth (b) covered with a layer of sand and (c) covered with a glass sheet. On which surface will the marble move the shortest distance. Give reason for your answer. 7. When the cutting edge of a knife is put against a fast rotating stone to sharpen it, sparks are seen to fly. Explain the reason. 8. We have two identical metal sheets. One of them is rubbed with sand paper and the other with ordinary paper. The one rubbed with sand paper shines more than the other. Give reason. 80

PRACTICE SHEET - 5 (PS-5) 9. Ball bearings are used in X, it gives Y type of friction. What are X and Y? I. Choose the correct option: a. X- Refrigerator; Y- Static friction 1. In machines, friction is reduced in movingparts by: b. X- Generator; Y- Fluid friction a. Using lubricants b. Using powder c. X- Ceiling fan; Y- Rolling friction c. Using paints d. Using bleaches d. X- Motorcycle; Y- fluid friction 2. An object is at rest on a floor and a force is 10. Powder is sprinkled on a carrom board to applied to move that object. Which frictional reduce: forcecomes into act? A. Pressure a. Rolling friction b. Static friction B. Friction c. Fluid friction d. Sliding friction C. Force 3. A force which opposes motion is called: a. Gravitational force D. All the above b. Mechanical force II. Short Answer Questions: c. Frictional force 1. What is a spring balance? How it is related to d. Muscular force friction? 4. Which of the following has frictional force? 2. Mention advantages of friction. a. Ball moving on the ground 3. Let us observe two different situations here. b. Moving bicycle on the road A. An object is moving from point X to point Y in c. Boat moving on water air. d. Ball in the air B. An object is moving from point X to point Y in 5. Who among the following needs spikes on water. their shoes? Answer the following questions? a. Doctor I. Which object do you think encounters more b. Athlete c. Lawyer frictional force? d. Postman II. Which kind of frictional force you can 6. Friction depends upon: a. Smoothness/nature of substances observe in the above situation? b. Color III. What is the fluid resistance called? c. Height III. Long Answer Questions: d. Width 1. What is rolling friction? Explain with an 7. If we apply oil on the hinges of doors, the friction: example. a. Increases 2. Given below are different situations between b. Decreases c. No change type of object and the surface. d. Eliminated I. A smooth object is moving on a smooth 8. Striking a matchstick produces fire by: a. Chemical reaction surface. b. Physical reaction II. A smooth object is moving on a rough surface c. Magnetic induction d. Friction or a rough object is moving on a smooth surface. III. A rough object is moving on a rough surface. Answer the following questions. A. In which situation do you think the force of friction is higher? B. In which situation do you think the force of friction is lower? C. On which factor does force of friction depend according to above picture? D. What are the factors that affect force of friction? How do we increase friction. E. Does force of friction depends upon surface area of the object? 81

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Choose the correct option: (5 Marks) 1. Friction a. Produces heat b. Causes wear and tear c. Opposes motion d. All of these. III. Answer in a sentence: (3 Marks) 1. Why is powder sprinkled on the carom board before beginning the game? 2. Tyres need to be changed when grooves start 2. Why is an oil spill on the road more disappearing because: dangerous? a. Friction increases b. Friction decreases c. Loses attractiveness d. Both a and c 3. Aeroplanes have special design in order to 3. While walking on a pavement, is friction an a. Increase friction advantage or a disadvantage? b. Reduce friction c. To make them attractive d. None of these. 4. A washing machine pushed along the floor is IV. Answer in two or three sentences: (4 Marks) an example of 1. You might have noticed that when used for a a. Rolling friction long time, slippers with rubber soles become b. Sliding friction slippery. Explain the reason. c. Static friction d. Drag 5. If a girl sitting half way on a slide, does not 2. Cartilage is present in the joints of our body, slide down, it would be because of which helps in their smooth movement. With a. Gravity advancing age, this cartilage wears off. How b. Height would this affect the movement of joints? c. Friction d. Weight. II. Define the following: (3 Marks) 1. Frictional force: 2. Rolling friction 3. Drag 82

13. Sound Learning Outcomes At the end of this lesson, students will be able to: vibration. • Define vibration. • Define loudness and pitch. • Explain that sound is produced by a vibrating • Differentiate between audible and inaudible body. sounds. • Explain how sound is produced by humans. • Differentiate between noise and music. • Explain the various mediums for propagation of • Define noise pollution. sound. • List the harms of noise pollution. • Explain how we hear sound through our ears. • Suggest measures to limit noise pollution. • Define amplitude, time period and frequency of a Concept Map Sound How sound is Mediums of propagation Noise pollution, its produced and parameters of sound effects and measures to limit noise pollution Key Points • Plantation on the roadside and elsewhere can reduce noise pollution. • Sound is produced by vibrating objects. • In human beings, the vibration of the vocal Keywords – amplitude, eardrum, frequency, hertz (hz), larynx, loudness, noise, oscillation, pitch, cords produces sound. time-period, vibration, voice box, wind pipe • Sound travels through a medium (gas, liquid or 83 solid). It cannot travel in vacuum. • The eardrum senses the vibrations of sound, it sends the signals to the brain. This process is called hearing. • The number of oscillations or vibrations per second is called the frequency of oscillation. • The frequency is expressed in hertz (Hz). • Larger the amplitude of vibration, the louder is the sound. • Higher the frequency of vibration, the higher is the pitch and shriller is the sound. • Unpleasant sounds are called noise. • Excessive or unwanted sounds lead to noise pollution. Noise pollution may pose health problems for human beings. • Attempts should be made to minimise noise pollution.

13. Sound Work Plan COVERAGE DETAILS PRACTICE SHEET • Sound is produced by a vibrating body PS-1 CONCEPT • Sound produced by humans How sound is produced? PS-2 • Mediums of propagation Mediums of propagation and • Amplitude, time period and frequency of PS-3 parameters of sound. PS-4 vibration Self-evaluation Sheet Noise pollution , its effects • Loudness and pitch and measures to limit noise • Audible and inaudible sounds pollution. • Music and noise • Define noise pollution • Effects of noise pollution • Measures to limit noise pollution Worksheet for \"Sound\" Evaluation with self- check or peer check 84

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks: 1. The to and fro motion of an object is called ________. 2. In humans, the sound is produced by ___________. 3. Why we cannot see the vibration produced by the sound emitting bodies? 4. Which an object is vibrating when the following sounds are produced? a. Music of sitar or veena b. Buzzing sound of a bee c. Sound of a bursting balloon PRACTICE SHEET - 2 (PS-2) 1. Fill in the blanks: a. Unpleasant sounds are called ___________. b. Pleasant sounds are called _________. c. Range of audible frequencies for a human ear is _____. d. Sounds of frequencies less than about 20 vibrations per second (20 Hz) and higher than about 20,000 vibrations per second (20 kHz) that cannot be detected by the human ear are called _________. e. Loudness of sound depends on its _______. f. Pitch of a sound is determined by its _________. g. To and fro motion of an object is called ______. h. Frequency is expressed in ______. i. The thin stretched membrane of a human ear is called _______. j. Shrillness of a sound is determined by ____________. 2. Which among the sounds made by a cuckoo and the roar of a tiger have a higher pitch? Which factor determines the pitch? 3. How is loudness related to amplitude of sound? 4. What are the types of media through which sound can propagate? 5. Explain how we can hear sound through our ears. 6. Place a ringing bell in a closed jar and then remove air completely from the jar through vacuum pump. Can we hear the ringing sound? Give reason. PRACTICE SHEET - 3 (PS-3) I. Answer each of these questions: 1. Define noise pollution. 2. What sources in the home may lead to noise? 3. List some sources of noise pollution? 4. What are the harms of noise pollution? 5. Suggest measures to limit noise pollution. 85

PRACTICE SHEET - 4 (PS-4) I. Choose the correct option: 8. Normal human conversations range from: a. 10 to 20 dB 1. The sound created by the to and fro motion of an b. 60 to 75 dB object is called: c. 80 to 90 dB a. Frequency d. 100 to 120 dB b. Vibration 9. Unwanted sound is called: c. Pitch a. Noise d. Amplitude b. Vibrations 2. The loudness of sound depends upon: c. Music a. It's frequency d. Hymns b. It's time period 10. Bats can detect: c. It's amplitude a. Ultrasonic waves d. Its speed b. Radio waves 3. Which of the following statements is correct? c. Electromagnetic waves I. Sound is produced by vibration d. Infrared waves II. Sound requires medium for propagation II. Short Answer Questions: III. Light and sound both require a medium for 1. How does sound produced by a vibrating object propagation reach your ear? IV. Sound travels slower than light. 2. Suppose you and your friend are on a different a. I and II only planet, would you be able to hear the sound made b. I, II and III by your friend? c. II, III and IV only 3. A simple pendulum completes 15 oscillations in d. I, II and IV only 3 seconds. What is frequency and time period? 4. Loudness of sound is measured in: a. Decibel III. Long Answer Questions: b. Hertz c. Meter/sec 1. Explain about audible and inaudible d. Newton sound. 5. Pitch of a sound is determined by its: 2. Latha heard a big sound coming far away from a. Frequency her place. When a small nail was dropped, she b. Amplitude couldn't hear any sound. Why can we not hear c. Speed feeble sounds from far distances? d. Loudness 6. In which of the following, is the speed of sound the least? a. Air b. Water c. Vacuum d. Wood 7. Which among the following are harmful effects of noise pollution? a. Blindness b. Hearing impairment c. Dumbness d. Fever 86