202110187-APEX-STUDENT-WORKBOOK-SCIENCE-G07-PART1

Science Workbook_7_P_1.pdf 1 18-10-2019 17:33:29 Name: ___________________________________ Section: ________________ Roll No.: _________ School: __________________________________

Table of Contents 1 18 1 FOOD COMPONENTS 39 2 ACIDS AND BASES 54 3 ANIMAL FIBRE 76 4 MOTION AND TIME 99 5 TEMPERATURE AND ITS MEASUREMENT 121 7 ELECTRICITY 8 AIR, WINDS AND CYCLONES 142 144 PROJECT BASED QUESTIONS ADDENDUM: ADDITIONAL AS-BASED PRACTICE QUESTIONS TABLE OF CONTENTS

1. FOOD COMPONENTS SESSION 1 ESSENTIAL COMPONENTS OF FOOD AND TESTS TO DETECT THEIR PRESENCE 1.1 Mind Map 1.2 Terminology i. Carbohydrate –A group of organic compounds that includes sugars, starches, celluloses. SESSION 1. ESSENTIAL COMPONENTS OF FOOD AND TESTS TO DETEC... 1

They serve as a major energy source in the diet of an organism. These compounds are produced by photosynthetic plants and contain only carbon, hydrogen and oxygen. ii. Fibres –Dietary material containing substances such as cellulose, lignin, and pectin, that are resistant to the action of digestive enzymes. iii. Proteins –A protein is an important component of food that is composed of carbon, hy- drogen, oxygen, nitrogen, and sometimes sulfur which are arranged as strands of amino acids. iv. Fats –is a component of food, comprising of various soft, solid, or semi –solid organic compounds, constituting the esters of glycerol and fatty acids and their associated organic groups. v. Vitamins –A group of organic compounds which are essential for normal growth and nutrition and are required in small quantities in the diet. They (with few exceptions) cannot be synthesized by the body. vi. Minerals – A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystalline structure, colour, and hardness. 1.3 Key Concepts i. Food supplies the energy we need to do many tasks in our day to day activities. ii. Our food consists of carbohydrates, proteins, fats, vitamins and minerals. Besides these, water and fibres are also present. iii. Carbohydrates present in the form of starch in food can be tested using iodine solu- tion. iv. The presence of fats may be tested using the translucent paper patch test. v. Proteins may be tested using Sodium hydroxide solution (Caustic soda solution) and Copper sulphate solution. vi. Growing children and adolescents need more protein containing food like milk, meat, pulses etc. 1.4 Conceptual Understanding Q1. Make a list of food items that contain all components of food. [Refer to TB page 7 Q3] A. A list of food items that contain all components of food are: i. Rice: Major component is starch (carbohydrates) and it contains a little protein and minerals. SESSION 1. ESSENTIAL COMPONENTS OF FOOD AND TESTS TO DETEC... 2

ii. Milk: Large part of it is protein. It also contains small portions of carbohydrates, fats, minerals and vitamins. iii. Egg: Large part of it is protein. Fats, minerals, vitamins are also present. iv. Beans: Large part of it is protein. A little quantity of vitamins, proteins and roughage are also present. v. Watermelon: A large part of it is water and it also contains small portions of carbohydrates, vitamins and proteins. vi. Groundnuts: Contain fats, minerals and vitamins. Q2. Who am I? [Refer to TB page 7 Q4] a. I am a component of food that makes paper translucent. b. Put a drop of me on a cut potato and it turns black. A. a. Fats b. Iodine solution Q3. Make a list of food items eaten during lunch by you. Try to mention the components in each food item. [Refer to TB page 7 Q1] A. Some items have been filled. Based on what you eat for lunch, complete the table. Food item taken Components of 1. Rice food item 2. Dal 3. Curd Carbohydrates Proteins Fat, proteins, vitamins SESSION 1. ESSENTIAL COMPONENTS OF FOOD AND TESTS TO DETEC... 3

Students’ Activity. 1.5 Experimentation and Field Investigation Q1. Test the given food items and record the type of components that are present in them (groundnut, cooked dal, pulusu). [Refer to TB page 7 Q6] A. i. Groundnut: • Take a small quantity of groundnuts. Rub them gently on a piece of paper. • The paper turns translucent, so groundnuts contain fats. • Some groundnuts are taken. They are ground to a powder and the powder is taken in a test tube. • 10 drops of water is added to the powder in the test tube. 2 drops of 2% copper sulphate solution and 10 drops of 10% sodium hydroxide solution are added to the groundnut solution already prepared. The colour of the solution changes to purple confirming the presence of protein in groundnut. ii. Cooked dal: • A sample of cooked dal solution is taken. • 10 drops of this solution is taken in a test tube. • 2 drops of 2% copper sulphate solution and 10 drops of 10% sodium hydroxide solution are added to the dal solution taken in the test tube. • The colour of the solution changes to purple confirming the presence of protein incooked dal. • This test confirms the presence of proteins in dal. iii. Pulusu: • A sample of pulusu solution is taken in a test tube. • If a drop of it is put on a paper, the paper becomes translucent confirming the presence of fat in pulusu. SESSION 1. ESSENTIAL COMPONENTS OF FOOD AND TESTS TO DETEC... 4

SESSION 2 ROUGHAGE, WATER AND BALANCED DIET 2.1 Mind Map SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 5

2.2 Terminology i. Balanced diet – A diet containing all the nutrients and other components in proper proportion is called balanced diet. ii. Constipation – Constipation (also known as costiveness or dyschezia) refers to bowel movements that are infrequent or hard to pass. iii. Roughage –Fibrous indigestible material in vegetable foodstuffs which aids the pas- sage of food and waste products through the gut. 2.3 Key Concepts i. There are some components of food that are necessary for our body called roughages or dietary fibres. ii. Bran, shredded wheat, cereals, fruits and vegetables, sweet and plain potato, peas and berries, pumpkins, palak, apples, banana, papaya and many kinds of beans are the sources of roughages. iii. Water is also an essential component needed by our body. iv. Most vegetables like potatoes, beans, kheera, tomatoes, gourds and fruits like apples, papaya and melons etc. contain water. v. Water is food and it also helps the food to move easily in the digestive tract. SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 6

vi. A diet containing food items having more of carbohydrates and protein along with a little fat, vitamins and minerals makes a balanced diet. 2.4 Conceptual Understanding Q1. If you were invited to a party with many food items in the menu like: Rice, Roti, Puri, Idly, Dosa, Samosa, Dal, Green salad, Vegetable curry, Fruit chat, Chicken curry, Eggs, Mutton Curry, Gulab jamun etc., what food items would come on to your plate to make your diet a balanced one? What food items would you take in plenty and adequately? [Refer to TB page 7 Q8] A. i. A diet containing all the nutrients and other components in proper proportion is called balanced diet. ii. To make my diet a balanced one, the following food items would come to my plate eg: rice, roti, green salad, dal, vegetable curry, fruit chat, chicken curry would come to my plate. iii. Foods containing vitamins and minerals should be taken in plenty: vegetable curry, fruit chat and green salad. iv. Foods containing carbohydrates and proteins should be taken adequately: dal, dosa, idly, roti and rice. Q2. Match the following: [Refer to TB page 8 Q11] Type of food Ans Function Fibre (A)Energy giving (B)Body building Protein (C)Micro–nutrients Vitamins and (D)Bulk forming minerals Carbohydrates SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 7

A. Type of food Ans Function Fibre D Bulk forming Protein B Body building Vitamins and C Micro–nutrients minerals Carbohydrates A Energy giving Q3. Fill in the blanks: [Refer to TB page 8 Q10] i. If our food is not balanced with proper nutrients we may . ii. Fibres in our diet prevent . iii. Our daily diet should include plenty of . iv. Oils and fats give us . A. i. If our food is not balanced with proper nutrients we may suffer from malnutrition. ii. Fibres in our diet prevent constipation. iii. Our daily diet should include plenty of fruits and vegetables. iv. Oils and fats give us energy. Q4. Manjula eats only bread and omelettes daily. Do you think it is a balanced diet? Why? Why not? [Refer to TB page 7 Q2] A. i. This is not a balanced diet. Bread is prepared from wheat flour and baking soda with a little sugar. ii. Most of the nutrients are carbohydrates. The omelettes that Manjula eats contain proteins, fats and a few minerals. iii. So roughage, minerals, vitamins B2, B12, C and D are not present in the food that Manjula eats. iv. She has to add some more components to her daily diet. Q5. Explain what would happen if we don’t include roughage in our food? [Refer to TB page 7 Q5] SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 8

A. i. Roughage are a kind of carbohydrates that our body fails to digest, so they help in free bowel movement in the digestive tract and prevent constipation. ii. Therefore, it is important to include roughage in our food. Q6. How is water useful to our body? [Refer to TB page 8 Q9] A. Water is useful to our body because of the following reasons: i. It helps food to move easily in the digestive tract. ii. It helps in the chemical processes which food undergoes during digestion. iii. It keeps the blood in a liquid form. iv. It helps in removing wastes from the body which is excreted as urine. v. It helps to maintain the balance of electrolytes in our body. 2.5 Experimentation and Field Investigation Q1. Observe whether your mother cooks on a low flame or high flame. Discuss with your mother and find out the reason. [Refer to TB page 8 Q14] A. My mother changes the range of flame while cooking. The reasons are described below: Condition Reason Low flame Vitamins like ascorbic acid (vitamin C) are destroyed by High Flame heating under high temperatures. Carbohydrates are also charred at high temperatures. So, my mother uses a low flame in cooking such food items. For preparing deep fries, for cooking rice and vegetables, high flame is needed. SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 9

2.6 Information Skills and Projects Q1. Prepare a balanced diet chart and exhibit it in your class room science fair. [Refer to TB page 8 Q12] A. Students’ Activity. Sample answer is provided below. Q2. Prepare ‘khichdi’ with your mother’s help using all kinds of available vegetables, dals, nuts etc. Write a note on the process of making khichdi. [Refer to TB page 8 Q13] A. Students’ Activity. Sample answer has been provided as reference. i. Wash and soak rice and dal together for half an hour. Pressure cook with 3 cups of water and a little salt. ii. Heat oil + ghee in a pan, add cumin seeds, bay leaf and curry leaves. When cumin seeds sizzle, add chopped onion, garlic, ginger and green chilli. Saute until onion browns lightly. SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 10

iii. Add chopped tomatoes, beans, peas, turmeric powder, chilli powder and salt needed. iv. Cook until tomatoes turn soft and mushy. v. Add the cooked rice and dal mixture to the onion tomato mixture. vi. Add 1 1/2 cup of warm water and mix everything well. Cook on low heat for 3–4 minutes or until everything gets blended well. Check for salt by tasting the khichdi. Add if required. vii. Drizzle a tsp of ghee and serve piping hot 2.7 Communication Through Drawing and Model Making Q1. Draw some food items of your diet and explain why you like them. [Refer to TB page 7 Q7] A. Students’ Activity. Given below are the examples of some food items. Students can add food items of their own choice. These food items gives taste and energy. Also they serve the purpose of balanced diet. Juices are the source of water in the body and keeps us fresh. Fruits contains essential vitamins and minerals. SESSION 2. ROUGHAGE, WATER AND BALANCED DIET 11

—— CCE Based Practice Questions —— AS1-Conceptual Understanding Very Short Answer Type Questions 1. Answer the following questions in one sentence. [Refer to Session 1.1 ] (i) List any 5 essential components of food. (ii) Which foods show the presence of starch? (iii) What are the nutrients present in milk? (iv) Which component of food can you identify in potatoes? (v) Which food items contain more fat? (vi) Which food items contain more protein? 2. Answer the following questions in one sentence. [Refer to Session 1.2 ] (vii) Give any two reasons, why water is useful for our body. (viii) What are the components of a balanced diet? (ix) Mention the names of any five fruits which contain water in them. (x) Classify the following foods into ‘eaten moderately, plenty, sparingly’. Cooking oils, Cheese, Fruits, Ghee, Leafy vegetables, Animal foods 3. Fill in the blanks. [Refer to Session 1.2 ] (xi) If our food is not balanced with proper nutrients, it causes . CHAPTER 1. FOOD COMPONENTS 12

(xii) Fibers in our diet helps in preventing . . (xiii) Our daily diet should include plenty of (xiv) Oils and fats are essential for . (xv) food causes damage to our digestive system. Short Answer Type Questions 4. Answer the following questions in 3-4 sentences. (i) [(Session 1.1)] Who am I? i. I am a component of food that turns the solution of Copper Sulphate and Sodium Hydroxide to violet or purple colour. ii. I am a component of food that turns paper translucent. iii. I turn the solution of Iodine to dark blue or blackcolour. (ii) [(Session 1.1)] Milk contain most of the components of food. List them. 5. Answer the following questions in 3-4 sentences. (i) [(Session 1.2)] What is roughage? What are the sources of roughage? (ii) [(Session 1.2)] Does every person need to take the same type of food? Explain. AS2-Asking questions and making hypothesis Very Short Answer Type Questions 6. Answer the following questions in one sentence. [Refer to Session 1.1 ] (i) Potato pieces when soaked in water, water becomes white in colour. Give reason. Short Answer Type Questions 7. Answer the following questions in 3-4 sentences. (i) [(Session 1.1)] Sahani ‘s friend was suffering with bleeding gums. Doctor advised her to use Limcee tablets. Many doubts raised in her mind about doctor’s advice. What questions she can ask her friend to clarify her doubts. CHAPTER 1. FOOD COMPONENTS 13

8. Answer the following questions in 3-4 sentences. (i) [(Session 1.2)] Does everyone require balanced diet? Give reason. (ii) [(Session 1.2)] Madhu observed a board written ’Stay healthy, Avoid junk food’ when she went to market with her mother. She had many doubts after seeing that caption. What doubts she could have asked her mother to clarify about junk food? AS3-Experimentation and field investigation Short Answer Type Questions 9. Answer the following questions in 3-4 sentences. (i) [(Session 1.1)] Test the given food items and record the type of components that are present in them. i. Chapatis ii. Dosa iii. Potato 10. Answer the following questions in 3-4 sentences. (i) [(Session 1.2)] Observe the below data found behind a potato chips packet. Answer the below questions. Nutritional Information (approx.) Per Per 14g 100g Energy kcal 76 544 Protein g 1.0 7.0 Carbohydrate g 7.7 54.7 Sugars g 1.1 7.6 Fat g 4.6 33 Saturated Fat g 1.2 8.7 MUFA g 2.1 14.9 PUFA g 1.3 9.3 Trans Fat g 00 Cholesterol mg 0 0 CHAPTER 1. FOOD COMPONENTS 14

i. What are the components found in the packet? ii. How much fat did they give? iii. What amount of sugar is present in it? iv. Will eating only chips provide us with a balanced diet? (ii) [(Session 1.2)] Write an experiment to show that water helps in moving our food in digestive tract. Long Answer Type Questions 11. Answer the following questions in 6-8 sentences. (i) [(Session 1.1)] How can you confirm the presence of protein in the given food? (ii) [(Session 1.1)] Are fats essential for the body? Can you write an experimental proce- dure to prove the presence of fat in food? AS4-Information skills and projects Long Answer Type Questions 12. Answer the following questions in 6-8 sentences. (i) [(Session 1.1)] You have learnt about food components, how they are tested, why they are useful. Now try to answer the following questions: i. Where do people get energy from? ii. How does the energy from food get into the body? iii. What happens to indigestible parts of the body? iv. What does your body use the nutrients in protein for? v. Why do you feel a quick burst of energy after eating foods with a lot of sugar? vi. What do carbohydrates offer the body? vii. What is broccoli made up of? viii. What happens to fibre in the body? ix. If your body didn’t get enough nutrients, what do you think would happen? x. What is pasta largely made up of? CHAPTER 1. FOOD COMPONENTS 15

AS5-Communication through drawing and model making Long Answer Type Questions 13. Answer the following questions in 6-8 sentences. (i) [(Session 1.2)] Prepare a diet chart for infants and adults. AS7-Application to daily life, concern to bio diversity Short Answer Type Questions 14. Answer the following questions in 3-4 sentences. (i) [(Session 1.2)] What is the component present in peas, beans, lentils etc. which are available in the market? How are they useful to our body? Long Answer Type Questions 15. Answer the following questions in 6-8 sentences. (i) [(Session 1.2)] What happens if we don’t take proper balanced diet? What can we contribute to the society if we stay fit? Objective Questions AS1-Conceptual Understanding 16. Choose the correct answer. (i) Iodine is used to test the presence of following component in our food. (A) Carbohydrates (B) Proteins (C) Fats (D) Minerals (ii) Which component is present more in a potato? (A) Fat (B) Starch (C) Protein (D) Fibre (iii) Milk is essential for growth as it provides (A) Water (B) Mineral (C) Vitamins (D) Protein (iv) Which among the following foods contain more fiber? CHAPTER 1. FOOD COMPONENTS 16

(A) Water (B) Fruits (C) Rice (D) Milk (v) Which component of food when rubbed on paper makes it translucent? (A) Fats (B) Starch (C) Proteins (D) Fibre (vi) Our body needs water because (A) It helps the blood to be in liquid form. (B) It helps to maintain the balance of electrolytes in our body (C)It helps in digestion of food. (D)All the above. (vii) Roughages are essential in our daily food. Which of the following food component doesn’t have roughages? (A) Egg (B) Brown rice (C) Berries (D) Peas (viii) Eating a lot of junk food affects our (A) Digestive system (B) Immune system (C)Nervous system (D)Respiratory system (ix) Our everyday diet should contain more of (A) Ghee and cheese (B) Pizzas and sandwiches (C)Salads and vegetables (D)Water and juices (x) A balanced diet consists of which of the following? (A) Carbohydrates and proteins (B) Vitamins and minerals (C) Fibers (D)All of the above CHAPTER 1. FOOD COMPONENTS 17

SESSION 1 2. ACIDS AND BASES 1.1 Mind Map INTRODUCTION AND INDICATORS 1.2 Terminology i. Indicator – Indicators are substances which show or indicate whether the substance tested is basic or acidic or neutral. ii. Acid – An acid is a chemical substance whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals (like calcium) to form salts. iii. Base –Bases are substances that, in aqueous solution, are slippery to the touch, taste bitter, change the colour of indicators (e.g., turn red litmus paper blue), react with acidsto form salts. SESSION 1. INTRODUCTION AND INDICATORS 18

1.3 Key Concepts i. The substances which indicate a change in colour when some substances are added to them are known as indicators. ii. The acidic, basic or neutral nature of any solution is identified by using an indicator. iii. The strips of litmus paper change the colour, based on the nature of the material put on them. 1.4 Conceptual Understanding Q1. When drops of lemon juice are put on a blue litmus paper, it turns red. What will happen if you put some drops of soap solution at the same place on the litmus paper? [Refer to TB page 17 Q4] A. i. When a few drops of lemon juice are put on a blue litmus paper, it turns red. ii. If some drops of soap solution are put on the same place of litmus paper it again turns blue. iii. The reason is, soap solution is basic in nature and bases turn red litmus to blue colour. Q2. Turmeric stains on white clothes, when washed with soap, turn red. Why? [Refer to TB page 17 Q6] A. The turmeric stains on white clothes, when washed with soap, turn red. It is because soap solution is basic in nature. Q3. Red litmus paper is dipped in a solution. It remains red. What is the nature of the solution? Explain your answer. [Refer to TB page 17 Q9] A. It shows that the solution is not basic. It may be acidic or neutral. Q4. Can flowers and turmeric papers also be called indicators? Why? [Refer to TB page 17 Q11] A. Yes, flowers such as Hibiscus (Mandara) and turmeric papers can also be used as indicators because they change their colour in acidic or basic substances. SESSION 1. INTRODUCTION AND INDICATORS 19

Q5. Correct the statement if it is wrong: [Refer to TB page 17 Q12] (a) Indicators show different colours in acidic and basic solutions. (b) Sodium hydroxide turns blue litmus red. (c) Tooth decay is caused by the presence of base. A. (a) Correct. (b) Not correct. Sodium hydroxide is a base. So it turns red litmus to blue colour. (c) Not correct. If food particles settle in tooth cavities, they become rotten and acids are formed. These acids cause tooth decay. Q6. Ammonia is present in window cleaners. It turns red litmus blue. What is its nature? [Refer to TB page 17 Q7] A. Since ammonia turns red litmus blue, we can say that it is basic in nature. Q7. What is the effect of basic substances on turmeric paper? [Refer to TB page 17 Q10] A. Basic substances turn turmeric paper red. 1.5 Asking Questions and Making Hypothesis Q1. What is the nature of urea? Is it acidic, basic or neutral? How can you verify it? [Refer to TB page 17 Q8] A. i. Urea is acidic in nature as it contains uric acid. ii. We can verify it by dropping a blue litmus paper in a sample of urea. iii. The colour of blue litmus turns red indicating that urea is acidic. 1.6 Experimentation and Field Investigation Q1. Test the nature of lemon juice and milk sample with the help of natural indicators pre- pared from different flowers. Explain their nature. [Refer to TB page 18 Q17] SESSION 1. INTRODUCTION AND INDICATORS 20

A. Preparing a natural indicator using flowers: i. Collect some hibiscus flowers. ii. Remove their petals and keep them in a beaker. iii. Add some warm water. Keep the mixture for some time till the water becomes coloured or we can boil the mixture of water and petals for sometime. iv. Now strain the solution. v. The filtrate solution can now be used as an indicator. Testing lemon juice: When we add a few drops of lemon juice, the hibiscus indicator turns the solution dark pink or magenta colour. So lemon juice is acidic in nature. Testing milk sample: When we add a few drops of the above indicator to milk sample it may or may not change its colour. Milk may be slightly acidic in nature to neutral. (Note: The pH of milk ranges from 6.5 to 6.7) The same process may be repeated for the samples with indicators solutions made of different flowers. Q2. Take vinegar, lemon juice, soap water, and baking soda in different vessels. Put beetroot pieces in the vessels. Predict what happens. Verify your prediction by observing the changes. After 10 minutes, 30 minutes, and 60 minutes, record your observations. What do you conclude? [Refer to TB page 17 Q13] A. Students’ Activity Prediction–The lemon juice and vinegar have no effect on beetroot as they are acidic in nature. Soap water and baking soda change the colour of beetroot pieces to a different colour as they are bases.[Note–Prediction may vary from student to student] Hints–Vinegar and Lemon juice being strong acid will show pink/red/brownish red color and Soap Water and Baking Soda being strong base show pale yellow colour/Yellow colour. Q3. Prepare red cabbage juice by boiling a piece of red cabbage in water. Use it as an indicator and test acidic and basic solutions with it. Present your observations in the form of a table. [Refer to TB page 18 Q15] SESSION 1. INTRODUCTION AND INDICATORS 21

A. i. Red cabbage is cut into quarters. It is placed in a pot with a cup full of water and boiled. ii. After about fifteen to twenty minutes, turn off the stove. iii. Cut some plain white paper into small strips. When the pot’s content has cooled, transfer the cabbage water to a glass and dip several strips into it. iv. Place them on a wax paper to dry. v. Use this homemade indicator to test lemon juice (an acid) and baking soda mixed with water (a base). vi. The observations are recorded. S. No. Substance Colour 1. Vinegar Red 2. Lemon Red 3. Apple Red 4. Tomato Pink 5. Banana Pink 6. Pink 7. Milk Pink 8. Water Blue 9. Baking soda Pink 10. Soap Greenish yellow 11. Milk of Magnesia Greenish Blue 12. Ammonia Blue 13. Egg white Greenish yellow Caustic soda SESSION 1. INTRODUCTION AND INDICATORS 22

1.7 Information Skills and Projects Q1. Collect different flowers and prepare their natural indicators with the help of filter papers. [Refer to TB page 18 Q16] A. The following flowers can be used to make natural indicators: Hibiscus and Oleander. Procedure to make natural indicator using hibiscus: i. Collect mature hibiscus flowers and separate their petals. ii. Place them in warm water or boil it for sometime in moderate heat so that the colour leaches out. iii. Filter the solution and your indicator is ready. 1.8 Application to Daily Life, Concern to Bio Diversity Q1. How do you feel about nature? It is a big natural laboratory that contains innumerable indicators. [Refer to TB page 18 Q18] A. i. Nature is a huge laboratory. ii. There are flowers like hibiscus and rose, and indicators like turmeric, acorn, red cabbage and litmus. iii. Litmus is derived from lichens and the others are derived from plants. iv. So nature itself is a big laboratory that contains innumerable indicators. SESSION 1. INTRODUCTION AND INDICATORS 23

SESSION 2 ACIDS AND BASES 2.1 Mind Map 2.2 Terminology i. Red litmus –A strip of paper impregnated with red litmus, used as a chemical indicator that turns blue under basic or alkaline condition. ii. Blue litmus – A strip of paper impregnated with blue litmus, used as a chemical indicator that turns red under acidic condition. iii. Acidic substance –The substances which are sour in taste and turns blue litmus red are called acidic substances. iv. Basic substance –The substances which are bitter in taste , soapy to touch and turns red litmus blue are called basic substances. v. Acid rain – Acid rain is a rain or any other form of precipitation that is unusually acidic. Acid rain is a combination of Carbonic acid, Sulphuric acid and Nitric acid with rain water. 2.3 Key Concepts i. Substances which are sour to taste are called acids. SESSION 2. ACIDS AND BASES 24

ii. Lemon juice, curds, butter milk, apples – all contain acids, they are all natural acids. iii. Some acids like hydrochloric acid and sulphuric acid are prepared from minerals. iv. The substances which are soapy to touch are basic in nature. Few examples are lime water, soaps, milk of magnesium etc. v. Acid rains are the combination of Carbonic acid, Sulphuric acid and Nitric acid with rain water. 2.4 Conceptual Understanding Q1. Match the following: [Refer to TB page 18 Q20] A. Q2. Choose the correct answer: [Refer to TB page 18 Q19] (a) To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is: (A) acidic (B) neutral (C) basic (D) baking soda (b) Which of the following is acidic in nature? (A) Lemon juice (B) Baking soda (C) Lime water (D) Antacid A. (a) (C) basic (b) (A) Lemon juice SESSION 2. ACIDS AND BASES 25

Q3. Why are acids not stored in metal containers? [Refer to TB page 17 Q2] A. i. Most of the common acids we use corrode metals. ii. They react with most of the metals except noble metals such as gold, silver and platinum. iii. So acids are stored only in containers made of glass, porcelain or plastic but not in metal containers. Q4. What happens when nitric acid is added to egg shell? [Refer to TB page 17 Q5] A. i. An egg shell contains a chemical called calcium carbonate. ii. The calcium carbonate reacts with nitric acid and releases carbon dioxide. iii.The carbon dioxide released can be tested with a drop of lime water taken on a glass rod. iv. The lime water changes to milky white colour. This is a test for carbon dioxide. SESSION 2. ACIDS AND BASES 26

SESSION 3 NEUTRALISATION AND SALTS 3.1 Mind Map 3.2 Terminology i. Neutralization – If an acid reacts with a base in the correct proportion we get salt and water. This is known as neutralization. ii. Salts –Any chemical compound formed from the reaction of an acid with a base. iii. Neutral substance – Neutral substance is a substance that shows no acid or base properties. SESSION 3. NEUTRALISATION AND SALTS 27

3.3 Key Concepts i. In the neutralisation process, when acid and base are mixed in equal concentration they become neutral. ii. An acid can be changed into base by adding base in excess. Similarly, a base is changed into acid by adding acid in excess. iii. When an acid and a base are mixed, a chemical reaction takes place and a salt is produced. iv. Formation of a salt depends on the type of an acid and a base. v. Salts which change blue litmus to red are acidic salts and salts which change red litmus to blue are basic salts. Some salts affect neither blue nor red litmus papers. These are called neutral salts. 3.4 Conceptual Understanding Q1. The sting of wasp is basic. How can you treat the sting of a wasp? [Refer to TB page 17 Q1] A. i. Since the sting of a wasp is basic, a dilute acid like lime juice is to be applied to the affected area. ii. As the acid neutralizes the base, the pain caused by the sting of the wasp is slowly relieved. 3.5 Asking Questions and Making Hypothesis Q1. Acidic, basic and neutral solutions are given in three test tubes and you are given a strip of red litmus. How will you identify the three solutions? [Refer to TB page 17 Q3] A. i. Drop a piece of red litmus in each of the three test tubes. ii. The test tube where the litmus paper turns blue contains a basic solution. iii. Drop this blue litmus paper in the other two test tubes. iv. The test tube where this litmus paper turns red contains an acidic solution. v. The test tube where no colour change is observed in both the cases contains a neutral solution. SESSION 3. NEUTRALISATION AND SALTS 28

3.6 Information Skills and Projects Q1. Visit a doctor. Find out the medicines he/ she prescribes to treat acidity. Ask him/ her how acidity can be naturally prevented. Prepare a report. [Refer to TB page 18 Q14] A. i. In the digestive system, hydrochloric acid is secreted in the walls of the stomach. ii. For various causes, acid may sometimes accumulate in the stomach. iii. This excess of acid in the stomach can be neutralised by using antacid tablets or syrups. iv. The antacid tablets contain magnesium hydroxide and aluminium hydroxide, which are bases. v. Fruits like banana, sapota, papaya, and butter, cream, honey and bitter things like bitter gourd etc. prevent acidity naturally. 3.7 Application to Daily Life, Concern to Bio Diversity Q1. Why industrial waste are neutralized before releasing in to water? [Refer to TB page 18 Q21] A. i. Factory wastes are neutralized before disposing into water bodies because, factory wastes often contain acid. ii. If it reaches a river, the acid will kill aquatic life and also may be hazardous to human health and plants. iii. This is prevented by adding a base called slaked lime. SESSION 3. NEUTRALISATION AND SALTS 29

—— CCE Based Practice Questions —— AS1-Conceptual Understanding Very Short Answer Type Questions 1. Match the following. Column B [(Session 2.3)] a. Sodium hydroxide Column A b. Neither affects blue litmus nor red lit- i. Food preservation mus ii. Washing clothes c. Washing soda iii. Making cakes iv. Caustic soda d. Baking soda v. Neutral salts e. Common salt 2. Fill in the blanks. . [Refer to Session 2.3 ] . (i) The vessels of copper and brass are coated inside with in nature. (ii) By the neutralization of HCl with caustic soda, salt is formed. (iii) A reaction in which an acid and a base participate is called . (iv) A reaction in which a salt is formed is called as (v) Salts may be CHAPTER 2. ACIDS AND BASES 30

3. State true or false. [Refer to Session 2.2 ] (vi) Soap water is acidic in nature. [ ] (vii) Acids contain mainly hydrogen ions. [ ] (viii) C.V. Raman discovered hydrogen gas. [ ] ] (ix) A burning matchstick in the presence of hydrogen gas keeps burning. ] [ (x) Nitrogen dioxide can’t turn lime water milky. [ 4. Answer the following questions in one sentence. [Refer to Session 2.2 ] (xi) Why do we feel a burning sensation when an ant bites us? (xii) Who discovered hydrogen gas? 5. Fill in the blanks. [Refer to Session 2.2 ] acid. (xiii) Explosives contain (xiv) Bases contain mainly ions. (xv) Antacid is in nature. (xvi) Tooth decay is caused by presence of . (xvii) Acidity can be treated by . CHAPTER 2. ACIDS AND BASES 31

6. Match the following. Column B [(Session 2.1)] a. Antacid Column A b. Calcium hydroxide c. Ammonium hydroxide i. Turmeric d. Natural indicator ii. Litmus paper e. Acid base indicator iii. Lime water iv. Milk of magnesia v. Glass cleaners 7. Answer the following questions in one sentence. [Refer to Session 2.1 ] (xviii) Give one example of natural indicator. 8. Fill in the blanks. [Refer to Session 2.1 ] (xix) Lime water turns a red litmus paper to colour. (xx) Common name of sodium chloride is . (xxi) A natural indicator commonly used in cooking is . (xxii) colour appears after mixing turmeric with soap water. (xxiii) Lime water turns milky white, due to gas. (xxiv) Methyl orange gives colour with acids. (xxv) Curd contains acid. Short Answer Type Questions 9. Answer the following questions in 3-4 sentences. (i) [(Session 2.2)] Why pickles and jams are preserved in glass, porcelain or plastic containers? (ii) [(Session 2.2)] How are the acid rains caused? CHAPTER 2. ACIDS AND BASES 32

(iii) [(Session 2.2)] Differentiate between acids and bases. Use below format. ACIDS BASES (iv) [(Session 2.2)] Why are the inner sides of vessels made up of brass and copper coated with another substance? Long Answer Type Questions 10. Answer the following questions in 6-8 sentences. (i) [(Session 2.3)] Why should industrial wastes be neutralized before releasing them into water bodies? 11. Answer the following questions in 6-8 sentences. (i) [(Session 2.2)] What are the properties of acidic, basic and neutral substances. How do they react with indicators? Give examples of each of them with any two indicators. Use below format. Serial Acids Bases Neutral No AS2-Asking questions and making hypothesis Very Short Answer Type Questions 12. Answer the following questions in one sentence. [Refer to Session 2.1 ] (i) Lemon juice, curds, butter milk and apples contain acids. Is this hypothesis correct? Give two reasons to support the hypothesis. Short Answer Type Questions 13. Answer the following questions in 3-4 sentences. (i) [(Session 2.3)] Sugar is neutral, so Raju thought that it is a salt. Do you agree with him? Write three reasons to support your answer. (ii) [(Session 2.3)] We apply lemon juice to treat the sting of a wasp. What questions would you ask to know whether the treatment is correct or not? CHAPTER 2. ACIDS AND BASES 33

14. Answer the following questions in 3-4 sentences. (i) [(Session 2.2)] Your friend has a bottle of milk of magnesia and another bottle of lemon juice. What questions would you ask him to understand the acidic or basic properties of these substances? AS3-Experimentation and field investigation Very Short Answer Type Questions 15. Answer the following questions in one sentence. [Refer to Session 2.1 ] (i) How can you prove that given solution is acidic? Short Answer Type Questions 16. Answer the following questions in 3-4 sentences. (i) [(Session 2.3)] Describe the process of neutralisation with the help of an experiment. 17. Answer the following questions in 3-4 sentences. (i) [(Session 2.2)] Do the following experiments and record your observations. i. What happens if you add nitric acid to eggshell? ii. What happens if you dip red litmus paper in sodium hydroxide solution? iii. What happens when you dip knife in methyl orange and cut the lemon? iv. If you neutralize hydrochloric acid with caustic soda what happens? 18. Answer the following questions in 3-4 sentences. (i) [(Session 2.1)] Turmeric stains on white clothes, when washed with soap turns red. What procedure would you follow to prove it? (ii) [(Session 2.1)] A red cabbage solution is used to test the acidic and basic nature of substances like soap, tomato and caustic soda. Describe the procedure you would use to test and note the colour changes. AS4-Information skills and projects Short Answer Type Questions 19. Answer the following questions in 3-4 sentences. (i) [(Session 2.1)] Do you know from where the litmus is obtained? What is the use of it? CHAPTER 2. ACIDS AND BASES 34

Long Answer Type Questions 20. Answer the following questions in 6-8 sentences. (i) [(Session 2.3)] Tamarind tastes sweet and sour. This is because of tartaric acid present in tamarind. Name the acid present in the below substances. Urine, Apple, Curd, Orange, Amla Substance Taste Acid Urine Apple Curd Orange Amla 21. Answer the following questions in 6-8 sentences. (i) [(Session 2.1)] Turmeric has medicinal properties and is a natural indicator. Record the changes in the table when the following substances are put on turmeric paper. Based on the information, indicate whether the substances are acidic, basic or neu- tral. Vinegar, Lime water, Soap, Banana Properties Vinegar Substances Soap Banana Lime Colour change water Acidic/ basic/ neutral CHAPTER 2. ACIDS AND BASES 35

AS5-Communication through drawing and model making Long Answer Type Questions 22. Answer the following questions in 6-8 sentences. (i) [(Session 2.2)] Prepare a chart of indicators, their pH values and the colour of the indicator, in acidic, basic neutral solutions. AS6-Appreciation and aesthetic sense, Values Short Answer Type Questions 23. Answer the following questions in 3-4 sentences. (i) [(Session 2.2)] Write some uses of acids in our daily life. AS7-Application to daily life, concern to bio diversity Short Answer Type Questions 24. Answer the following questions in 3-4 sentences. (i) [(Session 2.2)] Write down any four examples of bases which we use in our daily life? Long Answer Type Questions 25. Answer the following questions in 6-8 sentences. (i) [(Session 2.3)] If acids help in digestion of food in the human body, then why do we need antacids? Objective Questions AS1-Conceptual Understanding 26. Choose the correct answer. (i) The acid that is present in tomato is called (A) Citric Acid (B) Stearic Acid (C) Palmitic Acid (D)Oxalic Acid (ii) Henry Cavendish, an Italian scientist discovered a colourless gas called (A) Nitrogen (B) Oxygen (C) Hydrogen (D) Carbon–dioxide CHAPTER 2. ACIDS AND BASES 36

(iii) Milk of magnesia is chemically known as (A) Hydrogen peroxide (B) Nitrogen dioxide (C)Magnesium hydroxide (D)Calcium chloride (iv) Which substance when tested with red and blue litmus paper doesn’t change its colour (A) Milk (B) Mineral water (C)Lime water (D)Butter milk (v) A process in which a chemical reaction between acid and bases that produces salt is called (A) Solidification (B) Neutralisation (C) Condensation (D) Chlorination (vi) In which of the following solutions, phenolphthalein remains colourless? (A) Acidic solution (B) Basic solution (C)Neutral solution (D)Any solution (vii) Immediate remedy to treat sting of a wasp is (A) Application of lemon juice or vinegar (B) No (B) Application of milk of magnesia (D)Partially no (C)Application of palm oil (D)Application of buttermilk (viii) Sugar and starches are neutral. (A) Yes (C)Partially yes CHAPTER 2. ACIDS AND BASES 37

(ix) Substance which doesn’t change the colour of a blue or a red litmus paper is (A) Acidic in nature (B) Basic in nature (C)Neutral in nature (D)Raw in nature (x) Soaps contain one of the following bases (A) Ammonium hydroxide (B) Calcium hydroxide (C)Sodium hydroxide (D)Magnesium hydroxide CHAPTER 2. ACIDS AND BASES 38

SESSION 1 3. ANIMAL FIBRE 1.1 Mind Map INTRODUCTION AND STORY OF SILK 1.2 Terminology i. Animal fibre – Animal fibers are natural fibers that consist largely of particular proteins. ii. Silkworm – The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori. It is an economically important insect, being a primary producer of silk. iii. Cocoon – A protective case of silk or similar fibrous material spun by the larvae of moths and certain other insects as a cover for the pupa. iv. Mulberry –A small deciduous tree with broad leaves, native to East Asia and long cultivated elsewhere. v. Sericulture – Sericulture, or silk farming, is the rearing of silkworms for the production of silk. vi. Bombyx mori –Stocky creamy–white Asiatic moth found almost entirely under human care; the source of most of the silk commerce. vii. Reeling – Obtaining silk fibre from cocoons is called reeling. SESSION 1. INTRODUCTION AND STORY OF SILK 39

1.3 Key Concepts i. We get fibres from plants and animals. Cotton, Jute, Gongoora, Coconut fibres are some of the plant fibres, silk and wool are from animals. ii. Silk moths are locally called as ‘Chilakalu’, where as its scientific name is ‘Bombyx Mori’. iii. Serilculture is a process of obtaining silk starting from silk moth. iv. Silk worms eat mulberry leaves day and night to grow. When they grow bigger in size, it is transferred into big sized cane frames called “Chandrikalu” v. Caterpillar moves its mouth from side to side and secretes fibre–like substance. The net is woven completely to cover the body of the caterpillar which is called ‘Pattukay- alu’ (Cocoon). vi. Larve of silk worm is killed inside the cocoon by a process called stiffling. vii. Caterpillar of silkworm spins fiber which is mainly made up of two types of protein (sirisine and fibroin) and is very strong. viii. Obtaining silk fibre from cocoon is called reeling. It is done with special machines called ix. Silk yarn is woven to get silk fabric on handlooms or powerlooms. x. Banaras, Kanchipuram, Dharmavaram, Narayanpet, Kothakota, Pochampally are all types of silk fabrics. 1.4 Conceptual Understanding Q1. Why are cocoons stiffled? [Refer to TB page 26 Q4] A. Stifling of cocoons: i. The weavers kill the silkworm larvae inside the cocoons by a process called stiffling. ii. In this process, they put a lot of cocoons inside a steam oven for 10 to 15 minutes. iii. The cocoons have to be stiffled to kill the larva inside. iv. Otherwise, it cuts its way out after growing into a moth and spoils the cocoon. v. We will not be able to get a continuous thread of silk from such cocoons. vi. Thus we wont be able to obtain quality fibre for fabric. vii. Stiffling also helps to store the cocoons for a long time. Q2. What will happen, if cocoon is not boiled? [Refer to TB page 26 Q5] SESSION 1. INTRODUCTION AND STORY OF SILK 40

A. i. We boil the cocoons to kill the larvae. If this is not done, they open the cocoon after growing into a moth and spoil it. ii. Continuous silk fibres cannot be obtained from these cocoons. iii. Also, the caterpillar of silkworm spins the fibre which is mainly made up of two types of proteins, viz. sericin and fibroin. It is very strong. iv. The cocoons are to be boiled to loosen the fibre to be able to reel it. Q3. In sericulture industry, at which stages do silkworm weavers buy? Why do they do so? [Refer to TB page 26 Q1] A. i. Weavers buy silk yarn from reeling centres. In reeling centres, silk fibre is obtained from the cocoons. ii. The silk fibres are wound together to make yarn. Weavers buy this yarn and use it to make fabrics. iii. They buy yarn at this stage as it can be woven directly into fabrics like sarees. Q4. Which place in our state is called silk city? [Refer to TB page 26 Q2] A. Pochampally in our state is called the silk city. 1.5 Information Skills and Projects Q1. Observe designs on silk sarees, trace them in your notebook and make your own de- signs. [Refer to TB page 27 Q14] A. Students’ Activity. Q2. In East India silk is called pat. You may collect different pieces of silk fabric from a cloth store and write the names of the type of fabric and make a chart. [Refer to TB page 27 Q15] A. i. Some types of silk available at cloth shops are: ii. Mulberry silk: It is found in Karnataka, Andhra Pradesh and Tamil Nadu. iii. Tasar silk: It is found in Jharkhand, Chhattisgarh and Orissa. iv. Eri silk: It is found in the north eastern states, especially Assam and Bihar. v. Muga silk: It is found specifically is Assam. SESSION 1. INTRODUCTION AND STORY OF SILK 41

1.6 Communication Through Drawing and Model Making Q1. Prepare a chart showing life cycle of silk worm and display it in the class room. [Refer to TB page 26 Q3] A. SESSION 1. INTRODUCTION AND STORY OF SILK 42

SESSION 2 STORY OF WOOL 2.1 Mind Map 2.2 Terminology i. Fleece –The woolly covering of a sheep or goat. ii. Shearing – Removing of hair or fleece from the skin of a sheep is called shearing. iii. Scouring – Cleaning of fleece in a stream of water is called scouring. iv. Knitting –Knitting is the process of making fabric by using knitting needles to form interlocking loops and rings of woollen yarn. v. Bleaching –To remove colour or dirt by means of chemical agents or sunlight. vi. Weaving –A process to form fabric or a fabric item by interlacing long threads passing in one direction with others at a right angle to them. vii. Dyeing – Dyeing is the process of adding colour to textile products like fibers, yarns,and fabrics. viii. Warp threads – Woolen threads are stretched from the top of loom to the bottom. These are called warp threads. ix. Wool – The fine, soft, curly hair that forms the fleece of sheep and certain other animals. SESSION 2. STORY OF WOOL 43

2.3 Key Concepts i. Wool is obtained from hair of different types of animals like sheep, goat, yak, llama, camel, alpaca etc. ii. Wool is also called fleece or fur collectively. It is mainly composed of protein. iii. Removing of hair or fleece from the skin of a sheep is called shearing. iv. Sheared skin with hair is dipped in large tanks and stirred with a spade. The process of cleaning of hair to remove grease, dirt and dust is called washing or scouring. v. Unwanted materials like twigs or bits of leaves etc. that may be present with the wool are also separated out. This process is called sorting or wool classing. vi. The process of twisting wool into a thick and long thread is called spinning. vii. Knitting is the process of making fabric by using knitting needles to form interlocking oops and rings of woolen yarn. viii. Woolen threads are stretched from the top of loom to the bottom. These are called warp threads. 2.4 Conceptual Understanding Q1. Do you find any similarities between silk and wool weaving? What are they? [Refer to TB page 27 Q12] A. There are some similarities between silk and wool weaving. They are: i. In both cases we have the warp, the length wise threads arranged on looms. ii. In both cases, there are weft threads which go over one and under the adjacent warp thread alternately. iii. Both are woven on looms. Q2. What are the differences between fleece of an Angora goat and a camel? [Refer to TB page 26 Q6] A. S.No Angora Goat Camel 1. The fleece of Angora goat is 1. The fleece of soft and smooth. camel is rough and coarse. 2. It is used to weave costly 2. It is used to woollen fabric such as shawls make mufflers and and sweaters. stockings. SESSION 2. STORY OF WOOL 44

Q3. In what way is knitting different from weaving? [Refer to TB page 26 Q8] A. Knitting Weaving 1. Knitting is a special 1. A process to form fabric process, by making knots or a fabric item by interlacing with loops and rings of long long threads passing in one threads of yarn to make direction with others at a woollen fabrics. right angle to them. 2. Long needles are used in 2. Looms fitted with harness knitting. are used. Q4. Fill in the blank and give your reasons for the statement: fabrics protect us from the cold. [Refer to TB page 27 Q10] A. Woollen fabrics protect us from the cold. Reason: Wool is a poor conductor of heat. Air trapped in between the woollen fibres and our body prevents the flow of heat from our body into the surroundings. So we feel warm and are protected from cold. Q5. State five differences between wool and silk manufacturing. [Refer to TB page 27 Q13] A. Differences between wool and silk manufacturing: Wool Silk 1. Wool is sheared off the 1. Silk thread is obtained skin of goat, sheep or from cocoons of silkworm camel. after stiffling. 2. Wool is to be cleaned by 2. The silk thread doesn’t washing it in a stream of possess any grease and the water to which chemicals cocoons are not exposed to are added to remove grease dust. So such process is not and dust. necessary to clean the silk yarn. SESSION 2. STORY OF WOOL 45

3. Wool fibres are combed. 3. Such combing is not Wool is pulled through the necessary. many teeth of combing machine. 4. Wool can be knitted with 4. Silk cloth is to be knitting needles by making necessarily woven on a loops and rings. loom. 5. Woollen cloth is used to 5. Silk is used to make other make sweaters, shawls and products such as satin and blankets. crepe. 2.5 Communication Through Drawing and Model Making Q1. Make a flow chart showing various stages of production of woollen fabric. [Refer to TB page 26 Q7] A. SESSION 2. STORY OF WOOL 46

Q2. Prepare a scrap book with pictures of different wool yielding animals. [Refer to TB page 26 Q9] A. Students’ Activity. (Some animals that yield wool are camels, sheep, yak and goat.) 2.6 AApppplliiccaattiioonn ttoo DDaaiillyy LLiiffee,, CCoonncceerrnn ttoo BBiioo DDiivveerrssiittyy Q1. If you are going to visit Dal lake in Kashmir, which type of clothes would you pack in your luggage? Why? [Refer to TB page 27 Q11] A. i. Dal lake is situated in Kashmir at the lap of the Himalayan mountains which are covered by snow in all seasons. ii. I would like to pack woollen sweaters, woollen gloves, monkey cap made up of pure wool and woollen stockings in my luggage. iii. These woollen garments will protect me from the cold winds at Dal lake because wool is a poor conductor of heat and preserves my body heat. It will help me stay warm. SESSION 2. STORY OF WOOL 47

—— CCE Based Practice Questions —— AS1-Conceptual Understanding Very Short Answer Type Questions 1. Fill in the blanks. [Refer to Session 3.2 ] (i) fabric protects us from cold. (ii) Removing grease, dust and dirt from sheared skin of sheep by using stream of water is called as . (iii) Angora goat or Merino sheep have hair. (iv) Wool can be knit easily because it has a natural on it. (v) Camels have and hair. (vi) Wool is a conductor of heat. (vii) A Merino sheep yields about kg of wool every year. (viii) After washing the wool, is passed over it to make it softer. (ix) Good quality wool is obtained from sheep. 2. State true or false. [] [Refer to Session 3.1 ] [] (x) Obtaining silk fibre from cocoon is called shearing. (xi) Silk contains the protein keratin. CHAPTER 3. ANIMAL FIBRE 48