202110725-PERFORM-STUDENT-WORKBOOK-SCIENCE-G07-FY_Optimized

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins 1. Boojho’s uncle was hospitalised and put on specialised cells. They transport substances dialysis after a severe infection in both of his and form a two-way traffic in plants. Which kidneys. of the following terms qualify for the features a. What is dialysis? mentioned above? b. When does it become necessary to take a. Xylem tissue such a treatment? b. Vascular tissue c. Root hairs 2. Name the process and the organ which helps d. Phloem tissue in removing the following wastes from the body. 4. In a tall tree, which force is responsible for a. Carbon dioxide pulling water and minerals from the soil? b. Undigested food a. Gravitational force c. Urine b. Transportation force d. Sweat c. Suction force d. Conduction force I. Name the following. a. Products excreted by plants. IV. Answer the following. b. Process by which water is lost through 1. Paheli uprooted a rose plant from the soil. leaves. Most of the root tips, with root hairs got left c. The tissue that helps to conduct water in the behind in the soil. She planted it in a pot plant. with new soil and watered it regularly. Will the plant grow or die? Give reason for your II. True or false. answer. a. Phloem helps in transport of water. b. Transpiration helps in cooling the plant. III. Choose the correct alternative. 1. The vascular tissue in plants are a. Cambium and xylem b. Xylem and phloem c. Phloem and cambium d. None of these 2. Loss of water from the aerial parts of the plant is a. Diffusion b. Translocation c. Transpiration d. Respiration 3. They are pipe-like, consisting of a group of 89

12. Reproduction in Plants • Illustrate and label the structure of bisexual flower. • Define pollination. Learning Outcome • Explain the process of sexual reproduction in By the end of this chapter, you will be able to: plants. • Define reproduction. • List the post fertilisation changes seen in a flower. • Differentiate between sexual and asexual • Explain different agents of seed dispersion. reproduction. • Describe different methods of vegetative propagation. • Describe the structure of a bisexual flower. Concept Map Key Points • Some natural pollinating agents are insects, birds, wind and water. • In plants, asexual reproduction takes place by budding, fission, fragmentation, spore formation • The process of fusion of male and female gametes and by stem and root cuttings. to produce a zygote is called fertilization. • Vegetative propagation takes place with the help • The ovary of the flower grows into a fruit and of vegetative parts such as root, stem and leaves. ovules becomes the seeds. • Many methods of artificial propagation such as • Seeds have to be dispersed to prevent plants cutting, grafting and layering are used by plant from overcrowding and compete for air, minerals, breeders to get new varieties of plants with sunlight and soil. improved characters. • Agents for seed dispersal are air, water, animals • Flowering plants reproduce with the help of and self explosion mechanisms. flowers. The main reproductive part of a plant is 90 flower. Stamen and pistil are its male and female parts respectively. • Transfer of pollen grains from the anther to the stigma of a flower is called pollination. Pollination can be self pollination or cross pollination.

12. Reproduction in Plants Work Plan SUB CONCEPT PRACTICE SHEET SIMULATION/ VIDEO CONCEPT Vegetative Asexual reproduction • Vegetative propagation PS – 1 propagation • Budding • Fragmentation PS – 2 Structure of a • Spore formation PS – 3 flower Self-evaluation Sheet Sexual reproduction • Sexual reproduction in plants • Seed dispersal Worksheet for “Reproduction in Plants” Evaluation with self- check or Peer check* 91

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks with appropriate terms: 1. A flower is a __________________ part of a plant. 2. ___________ reproduces by budding. 3. Potato reproduces through the ______________. 4. Roots, stem and leaves form _______________ parts. 5. The phenomenon where in the pollen falls on the stigma is called _____________. II. Say whether the following statements are true or false. 1. Spirogyra reproduces by fragmentation. 2. In an asexual reproduction, seeds are formed. 3. Plants do not reproduce asexually. 4. Seeds of drumstick, maple and grasses are dispersed by wind. 5. Yeasts reproduce through formation of spores. III. Match the following: COLUMN I COLUMN II 1.  Unisexual flower a. Stem cuttings. 2. Fertilisation b. Bryophyllum 3.  Spore formation c. Papaya 4. Leaf propagation d. Fungus 5. Rose e. Results in seed formation IV. Choose the correct alternative. 1. Which of the following is not the vegetative part of the plant? a. Stem b. Roots c. Leaves d. Flowers 2. Spirogyra reproduces through: a. Spore formation b. Budding c. Fragmentation d. Cuttings 3. Which of these show asexual reproduction by budding? a. Yeast b. Hibiscus c. Apple d. All of these. 4. Which of these reproduce by spores? a. Spirogyra b. Algae c. Potato d. Fungus 5. Lila observed that a pond with clear water was covered up with a green algae within a week. By which method of reproduction did the algae spread so rapidly? a. Budding b. Sexual reproduction c. Fragmentation d. Pollination 92

PRACTICE SHEET - 1 (PS-1) V. Match the terms with their definitions and complete the magic box: DEFINITIONS TERMS 1. Plants that give rise to new plants forming seeds. a.  Asexual reproduction 2. Male reproductive part b.  Sexual reproduction 3. Fusion of male and female gamete. c. Bud 4. Transfer of pollen grains from stamen to stigma. d. Fragmentation 5. Plants give rise to new plants without formation of seeds. e. Stamens 6. Fertilization product of male and female gametes. f. Pistil 7. Flowers which contain both pistil and stamen. g. Unisexual flowers 8. Female reproductive part. h. Bisexual flowers 9. Transfer of pollen grains on to the stigma of the same i. Fertilization flower. j. Pollination 10. Small bulb like projection coming out of yeast cell. k. Self-pollination 11. A ripened ovary l. Cross pollination 12. Transfer of pollen onto the stigma of another flower of m. Zygote the same plant or another plant. n. Fruit 13. Flowers which contain only pistil or stamen. 14. P rocess where in an algae breaks down into 2 or more pieces and each piece develops into a new plant body. VI. Answer the following: 1. Fungus, moss and fern reproduce by a common method of asexual reproduction. Name the method. 2. Pick the odd one out from the following on the basis of mode of reproduction and give reasons for it: sugarcane, potato, rice, rose 93

PRACTICE SHEET - 2 (PS-2) I. Choose the correct option: 1. Young ones of their own kind are produced by a. Pollination b. Reproduction c. Fertilization d. Explosion 2. Which part of the flower converts to a fruit? a. Sepals b. Ovary c. Petals d. Ovules 3. Seeds with wings are dispersed by a. Water b. Air c. Self explosion d. Animals 4. Ovary wall becomes a _______________ after fertilisation. a. Fruit b. Embryo c. Seed d. Fruit wall 5. Which of the following parts of a plant take part in sexual reproduction? (i) Flower (ii)  Seed (iii) Fruit (iv) Branch Choose the correct answer from below. a. (i) and (ii) b. (i), (ii) and (iii) c. (iii) and (iv) d. (ii), (iii) and (iv) 6. Seeds of drumstick and maple are carried to long distances by wind because they possess a. Winged seeds b. Large and hairy seeds c. Long and ridged fruits d. Spiny seeds 7. The ovaries of different flowers may contain a. Only one ovule b. Many ovules c. One to many ovules d. Only two ovules 8. Which of the following statements is/are true for sexual reproduction in plants? (i)  Plants are obtained from seeds. (ii)  Two plants are always essential. (iii)  Fertilisation can occur only after pollination. (iv)  Only insects are agents of pollination. Choose from the options given below. a. (i)  and  (iii) b. (i)  only c. (ii) and  (iii) d. (i)  and  (iv) 94

PRACTICE SHEET - 2 (PS-2) 9. Pollination refers to the a. Transfer of pollen from anther to ovary. b. Transfer of male gametes from anther to stigma. c. Transfer of pollen from anther to stigma. d. Transfer of pollen from anther to ovule. II. Answer each of these questions. 1. Which type of pollination does the Fig indicate? 2. In the diagram given in Fig, label the parts marked (a), (b) and (c). 3. Group the seeds given in Fig (i) to (iii) according to their means of dispersion. a.  Seed dispersed by wind b.  Seed dispersed by water c.  Seed dispersed by animal 4. Coconut is a large and heavy fruit. How is it adapted for dispersal by water? 95

PRACTICE SHEET - 3 (PS-3) I. Choose the correct option 8. The slimy green patches in ponds, or in other stagnant water bodies called algae reproduce 1. Which of the following reproduce asexually? by _________________. a. Mango a. spore formation b. Potato b. fragmentation c. Tomato c. budding d. Brinjal d. seeds 2. The method by which you get a new rose plant 9. Asexual reproduction takes place with the help is: of ________ . a. Stem cutting a. vegetative parts b. Vegetation through eyes b. male part c. Vegetation through roots c. female part d. Vegetation through budding d. zygote 3. Transfer of pollen grains within the flower is 10. Which of the following is NOT a female repro- called ___________. ductive part in a plant? a. cross pollination a. Stigma b. self-pollination b. Style c. seed dispersal c. Stamens d. crisscross pollination d. Ovary 4. _____________ is an example of a complete II. Short answer questions flower. a. Papaya 1. What do you understand by unisexual and bisex- b. Bottle gourd ual flowers? Give two examples for each. c. Cucumber d. Hibiscus 2. How do you get a new potato plant? Explain. 3. Find out the information about types of repro- 5. _________ is a bisexual flower. a. Petunia duction in rose, sunflower, jasmine, and ashoka b. Bitter gourd tree. Prepare a report on it. c. Ridge gourd d. Cucumber III. Long answer questions 6. _________ develop into seeds. 1. What happens after fertilisation? a. Ovary 2. “Butterfly acts as an agent of pollination”. b. Fruits c. Ovules Justify. d. Stamens 7. In which of the following reproduction through spores takes place? a. Fern b. Fungus c. Algae d. Both (A) and (B) 96

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Fill in the blanks: (5 Marks) The male and female gametes fuse to form a __________ during the process of __________. This grows into an __________ which is enclosed within a seed. After fertilization the ovules develop into ___________ and the ovary develops into a _________ . II. In the figure of a flower given in Fig, label the parts whose functions are given below and give their names. (5 Marks) a. The part which contains pollen grains. b. The part where the female gamete is formed. c. The female reproductive part where pollen grains germinate. d. The colourful part of flower which attracts insects. III. Answer the following: 1. State any three different methods of asexual reproduction with an example. (3 marks) 2. Differentiate between self-pollination and cross pollination. (2 marks) 97

13. Motion and Time Learning Outcome By the end of this unit, a student will be able to: • Define time. • Define motion. • Explain the measurement of time. • Recall different types of motion. • Experimentally verify the time period of a simple • Cite examples for different types of motion. pendulum. • Define speed. • Interpret Distance-Time graphs. • Calculate speed using the formula. MOTIO•N APlNotDDTisItManEce -Time graphs. • State the units of speed. CCOonNcCeEpPTt MMaApP: MOTION AND TIME MOTION TIME Types of Speed Measurement Simple motion pendulum Circular Linear Periodic Definition of Calculation D-T graphs speed Interpretation Construction By the end of this unit, a student will be able to: 98  Define motion.  Recall different types of motion.  Cit examples for different types of motion.  Define speed.  Calculate speed using the formula.  State the units of speed.  Define time.  Explain the measurement of time.  Experimentally verify the time period of a simple pendulum.

13. Motion and Time Work Plan CONCEPT SUB CONCEPT ACTIVITY SKILL TIME Linear, circular and LESSON STARTER: Students brainstorm the Recalls 15 min periodic motions topic. Teacher asks students to complete Recognizes are the different Table 13.1 of the text individually and later types of motion. discusses the types of motion. Students are asked to observe the pictures Observes 15 min on page 144 of the text and determine the Reasons 10 min vehicles that moved fastest, faster and fast. Defines Speed is distance travelled by an From this, teacher and students discuss object in unit time. about speed and teacher defines speed. Calculation of Teacher takes the class outside. Teacher Records 25 min speed should also take 3 to 4 measuring tape and Derives 15 min divide the class into three or four groups. A distance of 100 m is marked. Students run individually a distance of 100m upward and 100m downward. Time taken by each student is recorded. All the members of the group run and their time is noted. Student Distance Time Speed Teacher and students get back to class and discuss how speed is calculated. From this discussion, students understand that Speed=Distance/Time taken Units of speed Now teacher draws the attention to derive the units of speed by posing the following questions: What is the unit of distance? What is the unit of time? How can you express km/h in m/s or m/min? From this discussion, students understand that speed is expressed as m/s or Km/h. Conversion factor from Km/h to m/s is also discussed. 99

13. Motion and Time Time Time –Units Time is measured using different units Recognizes 20 min Different like years, day, minute, seconds, micro or 20 min measurements of nanoseconds. Teacher explains about 12 time hour clock we normally use in clocks or 12 hour clock or 24 watches and usage of AM and PM to refer hour clock. time before 12 and after 12. Teacher also Evolution of clock explains about 24 hour clock commonly from the past to used in railways and airports. Teacher also the present. explains how clocks have evolved from the past to the present. Simple pendulum Students work in groups and complete Time period of a Activity 13.2 of NCERT. From this activity, simple pendulum students realize that the time period of a is a constant. pendulum remains the same. Measuring Speed Students work in small groups and complete 40 min Activity 13.3 of NCERT. Teacher again reiterates the conversion from km/h to m/s. Students complete Table 13.4. Distance Time Teacher explains the construction of a D-T Constructs 40 min graph graph and the slope of the graph gives the Interprets speed. Computes D-T graphs are given. Students work in groups and interpret the graphs and compute problems based on the graph. (Refer Annexure 1) Students work in groups and solve problems. Computes 40 min Teacher reiterates the concepts if needed. (Refer Annexure 2) Students write WS-1,2 and 3 40 min Students write WS 4 followed by peer check 40 min and discussion. Teacher and students discuss chapter end exercise. HW: Complete the chapter end exercise. 100

PRRAACCTTICICEESHSEHEETE-T5-(P1S(-P5S) -1) Time period I. Say True or False: 1. A sundial is more accurate than the quartz clock. 2. Speed is defined as the time taken by the object to move one kilometer. 3. Uniform motion is the motion in which an object travels equal distances in unequal intervals of time. 4. Unit of speed is m/s. 5. Slope of D-T graph gives the speed. II. Select the correct term for the description below: Non uniform motion Oscillation Simple pendulum Speed Uniform motion Speedometer Odometer 1. Distance covered by an object in unit time. 2. Consists of a small metallic ball or a piece of stone suspended from a rigid stand by a thread. 3. One to and fro motion of a bob. 4. Time taken to complete one oscillation. 5. Speed of an object along a straight line keeps on changing. 6. Speed of an object along a straight line remains constant. 7. An instrument that measures speed directly. 8. An instrument that measures distance. 101

PRRAACCTTICICEESHSEHEETE-T5-(P2S(-P5S) -2) 1. Plot a D-T graph for the following data: Time (min) Distance (km) 0 0 1 1 2 2 3 3 4 4 5 5 2. Plot a D-T graph for the following data: Time (min) Distance (km) 2 2 4 4 6 6 8 7 10 8 12 9 14 9 16 9 18 9 20 12 3. Plot a graph for the following data: Time (min) Distance (km) 2 2 4 4 6 6 8 7 10 10 12 12 14 14 16 16 18 18 102

PRRAACCTTICICEESHSEHEETE-T5-(P3S(-P5S) -3) The graph given in Figure is true for a. Both A and B. 1. Which of the following cannot be used for b. A only. measurement of time? c. B only. a. A leaking tap. d. Neither A nor B. b. Simple pendulum. c. Shadow of an object during the day. 4. A bus travels 54 km in 90 minutes. The speed d. Blinking of eyes. of the bus is a. 0.6 m/s 2. Two clocks A and B are shown in Figure. b. 10 m/s Clock A has an hour and a minute hand, c. m/s whereas clock B has an hour hand, minute d. 3.6 m/s hand as well as a second hand. Which of the following statement is correct for these 5. If we denote speed by S, distance by D and clocks? time by T, the relationship between these quantities is a. A time interval of 30 seconds can be a. S=DX T measured by clock A. b. T=S/D c. S=D/T b. A time interval of 30 seconds cannot be d. S=T/D measured by clock B. 6. Observe Figure. c. Time interval of 5 minutes can be measured The time period of a simple pendulum is the by both A and B. time taken by it to travel from d. Time interval of 4 minutes 10 seconds can a. A to B and back to A. be measured by clock A. b. O to A, A to B and B to A. c. B to A, A to B and B to O. 3. Two students were asked to plot a distance- d. A to B. time graph for the motion described by Table 7. Fig. shows an oscillating pendulum. Time A and Table B. taken by the bob to move from A to C is t1 and from C to O is t2. The time period of this simple pendulum is 103

PRRAACCTTICICEESHSEHEETE-T5-(P3S(-P5S) -3) a. (t1 + t2 ) b. 2 (t1 + t2 ) c. 3 (t1 + t2 ) d. 4 (t1 + t2 ) 8. The correct symbol to represent the speed of an object is a. 5 m/s b. 5 mp c. 5 m/s-1 d. 5 s/m 9. Boojho walks to his school which is at a distance of 3 km from his home in 30 minutes. On reaching he finds that the school is closed and comes back by a bicycle with his friend and reaches home in 20 minutes. His average speed in km/h is a. 8.3 b. 7.2 c. 5.0 d. 3.6 10. Which one of the following is not used for measuring of time? a. Pendulum b. Hour glass c. Metre scale d. Sun dial. 11. Which one of these is not a unit of time? a. m/s b. Week c. Month d. Year 12. Which one of these is a periodic motion? a. Rotation of earth about is axis. b. Revolution of moon about the earth c. To and fro motion of a vibrating spring d. All of these. 13. Conversion factor from km/h to m/s is a. 5/18 b. 18/5 c. 50/3 d. 5/3 14. In a distance time graph, uniform motion will be a a. Curved line b. Straight line c. A circle d. A bent line 15. If an object is travelling with uniform motion, its speed is equal to a. Total time taken b. Total distance covered. c. Total distance travelled /Time taken d. Total time taken in its first half of the motion. 104

PRRAACCTTICICEESHSEHEETE-T5-(P4S(-P5S) -4) I. Answer the following questions: 1. A simple pendulum is oscillating between two points A and B as shown in Figure. Is the motion of the bob uniform or non-uniform? 2. Paheli and Boojho have to cover different a. What will be the position of the object at distances to reach their school but they take 20s? the same time to reach the school. What can you say about their speed? b. What will be the distance travelled by the object in 12s? 3. If Boojho covers a certain distance in one hour and Paheli covers the same distance in c. What is the average speed of the object? two hours, who travels in a higher speed? 4. The average age of children of Class VII is 12 years and 3 months. Express this age in seconds. 5. A spaceship travels 36,000 km in one hour. Express its speed in km/s. 6. Starting from A, Paheli moves along a rectangular path ABCD as shown in Figure. She takes 2 minutes to travel each side. Plot a distance-time graph and explain whether the motion is uniform or non-uniform. 7. Plot a distance-time graph of the tip of the second hand of a clock by selecting 4 points on x-axis and y-axis respectively. The circumference of the circle traced by the second hand is 64 cm. 8. Given below as Figure is the distance-time graph of the motion an object. 105

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option 7. You might have observed the given image while 1. Which of the following is an example of periodic coming to school on your father’s scooter. What is the instrument called? motion? a. Odometer a. Car moving on a road b. Speedometer b. Earth moving around Sun c. Stopwatch c. Football kicked by a player d. Wristwatch d. Movement of a lift 8. An athlete runs 500 m in 1 m 40 sec. What is his 2. The bob of a simple pendulum is: speed in metres per second? a. The metallic ball a. 5 m/s b. The thread b. 8 m/s c. The hook c. m/s d. The support from which the thread d. 10 m/s is hung 9. I travel fastest of all. Who am I? 3. The motion of a simple pendulum is an example a. Sound of: b. Light a. Straight-line motion c. Wind b. Periodic motion d. Aero plane c. Oscillatory motion d. Both (B) and (C) 4. Which of the following statements is correct? 10. What do the points in the given graph repre- a. Length of a room is measured in km sent? b. The age of a person is measured in years a. Distance c. Distance between two villages is measured in b. Time cm c. Speed d. Your height is measured in mm d. Type of motion 5. Rockets attain speed of ________ , a. 8 cm/s b. 8 km/h c. 8 km/s d. 8 m/ s 6. Which of the following shows the straight-line motion? a. An arrow released from a bow b. Motion of a swing c. Motion of hands of a clock d. Motion of strings in Veena 106

PRACTICE SHEET - 5 (PS-5) II. Short answer questions 1. Observe following motions of bodies and label them as Rotatory (R), Straight-line (S) Sl. No Image Motion (R) /(S) Motion of the 1. blades of a ceiling fan 2. Motion of a top Motion of a rider on the bicycle 3. Motion of wheels of an object 2. A bus moves with a speed of 35 km/h for 30v minutes in the city and then with a speed of 70 km/h for the next 20 minutes on highway. Calculate the total distance covered by the bus: 3. “The to and fro motion of a simple pendulum is an example of a periodic or an oscillatory mo- tion.” Thus, can you say that all objects in peri- odic motion are in oscillatory motion? Discuss. III. Long answer questions 1. What are different types of motions. Explain. 2. i. Can an object be in two different types of mo- tions? Explain with examples. ii. Motion of an object is always relative. Justify with examples. 107

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Answer in a sentence: (5X1=5) 3. Differentiate between uniform motion and 1. Define an oscillation. non uniform motion. 2. What are the two methods of writing time in 4. How would you find out which vehicle is the a day? fastest? 3. Name the SI unit of time. 4. List the types of motion. 5. Looking at the bar graph, write down the 5. What does a speedometer measure? runs scored by a team in each over. II. Answer in brief: (5X2=10) 1. How is speed calculated? In what units are they generally expressed? 2. The average age of children of class 5 is 10 years, 3 months. Express this age in seconds. 108

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins III.  Answer as directed:  (2X5=10) 1. Distance between Bholu’s and Golu’s house is 9 km. Bholuhas to attend Golu’s birthday party at 7 o’clock. He started from his home at 6 o’clock on his bicycle and covered a distance of 6 km in 40 minutes. At that point he met Chintu and he spoke to him for 5 minutes and reached Golu’s birthday party at 7 o’clock. With what speed did he cover the second part of the journey? Calculate his average speed for the entire journey. 2. Boojho goes to the football ground to play football. The distance time graph of his journey from his home to the ground is given as Figure. a. What does the graph between point B and C indicate about the motion of Boojho? b. Is the motion between 0 to 4 minutes uniform or nonuniform? c. What is his speed between 8 and 12 minutes of his journey? 109

Annexure 1: Distance Time Graphs I. The following table shows the motion of a student walking into a classroom (the distance is measured from the door): Distance (meters) 01234566630 Time (seconds) 0 1 2 3 4 5 6 7 8 9 10 Draw a distance time graph (with time on the x-axis) to show the motion. II. Answer the questions below: 1. For the 6th to 8th second, what was the student’s movement? 2. How far into the classroom did the student move? 3. Where in the classroom was the student after 10 seconds? 4. Over which period of time did the student move the fastest? Can you explain how you know this? 5. How far in total did the student walk? 6. What was the average speed of the whole journey? 7. What was the velocity of the student at 9 seconds? (remember velocity has direction) 8. What was the velocity at 2 seconds? More difficult III. The following table represents a student riding a bicycle: Distance (meters) 0 4 12 24 40 60 84 84 84 84 72 60 48 36 24 12 0 Time (seconds) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Draw a distance time graph (with time on the x-axis) to show the motion. IV. Answer the questions below: 1. What is the bicycle doing for the first 6 seconds? 2. Describe the motion of the bicycle between 6 and 9 seconds. 3. What is the average speed of the bicycle? 4. What is the speed of the bicycle at 3 seconds? (hint: think tangents!) 5. How far away from the starting point is the bicycle after 8 seconds? 6. What is the bicycle doing between 9-16 seconds? 110

Annexure 1: Distance Time Graphs 1. The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train. 2. A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum? 3. Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school. 4. The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/halso. 5. Nancy travelled a distance of 455 km by car in 10 hours. Find the speed of the car. 6. Find the speed and average speed of a train which leaves Chennai at 1 p.m. and reaches Vijayawada in the same day at 9 p.m. The distance between the two stations is 432 km and the total time for stoppage is 2 hours between these stations. 7. A car travels a distance of 595 km in 8 ½ hours. What is its speed? 8. If a person drives his car in the speed 50 miles per hour, how far can he cover in 2.5 hours? 9. If a person travels at a speed of 40 miles per hour. At the same rate, how long will he take to cover 160 miles distance? 10. A person travels at a speed of 60 kms per hour. Then how many meters can he travel in 5 minutes? 111

14. Electric Current and its Effects Learning Outcome • Infers the importance of fuse in a circuit. • Explain the magnetic effect of current. By the end of this chapter, you will be able to: • Explain the working of an electromagnet. • Recall the components of the circuit. • Describe the construction of an electric bell. • Build a simple circuit. • Explain how an electric bell operates. • Assign the symbols to electric components. • Explain the heating effect of current. Concept Map Key Points • An electro magnet loses its magnetism as soon as the electric current is switched off. • The flow of electrons through a conductor gives rise to electric current. • Electric bell, cranes, hard disks, speakers, motors, generators have electromagnets and these are • An uninterrupted path through which electric some of the appliances that work on the magnetic current flows is known as a circuit. effects of current. • The conditions necessary for electric flow are a Key words: electricity, fuse, electromagnet, source of current, a conducting material and an conductor, wire, circuit, compass, current unbroken path for the flow of current. • Cells can be arranged in series or in parallel depending on the requirement. • An electric fuse is made up of alloy of tin and lead with a very low melting point. • A fuse acts as a safety device by breaking the circuit when more current flows suddenly. • Electric iron, electric geyser, heater, electric bulb and electric toaster are some of the appliances that work on the heating effect of current. • A current carrying conductor deflects the needle of a magnetic compass kept near it. 112

14. Electric Current and its Effects Work Plan CONCEPT SUB CONCEPT PRACTICE SHEET SIMULATION/VIDEO Electric circuit and • Symbols of components of PS – 1 Making simple electric its components circuit PS – 2 circuit by battery, safety PS – 3 pin, wires and a bulb • Function of each component Effect of current on a in the circuit compass needle Making an electromagnet • Conductor and insulator Working of an electric bell Heating effect of • Working of heating coil electric current • Working of heating iron • Working of fuse and its importance Magnetic effects of • Magnetic effect of electric electric current current • Electromagnet and its uses • Working of an electric bell Worksheet for “Electric Current and its Effects” PS – 4 Evaluation with self- Self-evaluation Sheet check or Peer check* 113

PRACTICE SHEET - 1 (PS-1) I. Fill In the blanks with appropriate terms: 1. An uninterrupted path through which electric current flows is known as __________. 2. Bulb has a filament made up of ______. 3. To connect or disconnect a circuit, a ______ is used. II. Draw the symbols of following components: CELL ELECTRIC BULB SWITCH IN ON POSITION SWITCH IN OFF POSITION BATTERY WIRE III. Choose the most appropriate answer for each of these statements: 1. Continuous flow of electric charge through a circuit requires a. Course of electric current b. Conducting material c. A closed circuit d. All of the above. 2. In a circuit diagram, the various components of the circuit are represented by a. Standard pictures b. Standard symbols c. Lines d. Circles 3. When a switch is in OFF position, i. Circuit starting from the positive terminal of the cell stops at the switch. ii. Circuit is open. iii. No current flows through it. iv. Current flows after some time. Choose the combination of correct answer from the following. a. All are correct b. (ii) and (iii) are correct c. Only (iv) is correct d. Only (i) and (ii) are correct 114

PRACTICE SHEET - 2 (PS-2) I. Write a word/term for the following statements: 1. An unbroken path through which an electric current can flow. 2. A very thin wire made up of special material that glows in a bulb. 3. Tightly wound coils found in appliances that heat up. 4. A safety device used to prevent the excessive flow of electric current. 5. A device used to open or close an electric current. II. Write one example for each: 1. One necessary component of an electric circuit. 2. A material used to make the filament of an electric bulb. 3. An appliance that is based on the heating effect of electric current. III. Say whether the following statements are true or false: 1. A bulb glows due to the silver wire present in it. 2. The element of electric iron is made up of copper. 3. A current carrying wire deflects the needle of a magnetic compass kept near it. 4. The electric fuse works on the principle of heating effect of current. IV. Answer each of these questions: 1. Which property of a conducting wire is utilised in making an electric fuse? 2. Name the device used these days in place of electric fuses in electrical circuits. 3. Paheli does not have a night lamp in her room. She covered the bulb of her room with a towel in the night to get dim light. Has she taken the right step? Give one reason to justify your answer. 4. Why are compact fluorescent lamps (CFLs) preferred over electric bulbs? 5. Why is an electric fuse required in all electrical appliances? V. Choose the correct option for each of these statements: 1. Which of the following is not a safety device used in an electric circuit? a. MCB magnet b. Magnet c. Electric fuse d. Cartridge fuse 2. Which of the following appliance does not use the heating effect of current? a. Electric heater b. Electric bell c. Electric geyser d. Electric bulb 3. The heating effect of electric current is used in a. An electric bulb b. An electric toaster c. A room heater d. All of these. 4. An electric fuse is a. An electric circuit b. A heating device c. An element in a bulb d. A safety device 115

PRACTICE SHEET - 3 (PS-3) I. Fill in the blanks: 1. An electric fuse has a____________ melting point. 2. Electric fuse works on the principle of ______________ of current. II. Match the following: COLUMN A COLUMN B 1. Heating effect of current a. Fuse 2. A horse shoe magnet b. MCB 3. A wire of low melting point c. Electric bell 4. A safety device in which the switch trips d. Electric iron down e. Tungsten 5. A wire of high resistance f. Electric current 6. Heating effect of current III. Answer in one/two words: 1. A magnet used in cranes. 2. A device that works on the magnetic effect of current. IV. Choose the correct alternative for each of these statements: 1. The strength of an electromagnet can be increased by a. Increasing number of coils b. Decreasing strength of current c. Decreasing number of coils d. All of the above methods. 2. What is the shape of the magnet in an electric bell? a. Cylindrical b. Bar c. Horse shoe d. Square 3. When an electric current flows through a wire, it a. Cools down b. Behaves like a magnet c. It boils d. Melts easily. 4. A hammer, a gong and a soft iron strip are all parts of a. An electromagnet b. An electric bell c. An electric fuse d. Electric circuit 116

PRACTICE SHEET - 3 (PS-3) 5. When an electric current flows through a copper wire AB as shown in Fig, the wire a. Deflects a magnetic needle placed near it. b. Becomes red hot. c. Gives electric shock. d. Behaves like a fuse. 6. Choose the statement which is not correct in the case of an electric fuse. a. Fuses are inserted in electric circuits of all buildings. b. There is a maximum limit on the current which can safely flow through the electric circuits. c. There is a minimum limit on the current which can safely flow in the electric circuits. d. If a proper fuse is inserted in a circuit it will blow off if current exceeds the safe limit. 7. Three bulbs A, B, C are connected in a circuit as shown in Fig. When the switch is ‘ON’ a. Bulb C will glow first. b. Bulb B and C will glow simultaneously and bulb A will glow after some time. c. All the bulbs A, B and C will glow at the same time. d. The bulbs will glow in the order A, B and C. 8. Which of the following precautions need not be taken while using electric gadgets/ appliances / circuit? a. We should never touch a lighted electric bulb connected to the mains. b. We should never experiment with the electric supply from the mains or a generator or an inverter. c. We should never use just any wire or strip of metal in place of a fuse. d. We should never turn the switch in ON position. 117

PRACTICE SHEET - 4 (PS-4) I. Choose the correct option 8. Damaged fluorescent tubes or CFLs need to be disposed off safely because they contain 1. On what factors is the amount of heat produced _______ which is toxic in nature. in a wire depend? a. Filament a. Nature of the material with which wire is made b. Hydrogen gas b. Thickness of the wire c. Water vapour c. Length of wire d. Nitrogen gas d. All of these II. Short answer questions 2. The coil that behaves like a magnet when 1. What is an electric fuse? What is its use? electric current flows through it is called 2. How do you make an electromagnet? Explain _______. a. Electric wire with a neat diagram. b. Fuse 3. Why should an electrician use rubber gloves c. Electromagnet d. Magnet while repairing an electric switch. Explain. 3. Dry cell is a source of electric energy. It converts: III. Long answer questions a. Electrical energy into chemical energy 1. Explain the working of an electric bell. b. Chemical energy into electrical energy 2. Differentiate between a cell and a battery. How c. Magnetic energy into electrical energy d. Electrical energy into magnetic energy do you make a battery? Show diagrammatically in two different ways. 4. Which of the following components is used to close or open an electric circuit? a. Fuse b. Switch c. Cell d. Battery 5. What happens when two or more cells are joined? a. They form a circuit b. They form a switch c. They form a battery d. They form a fuse 6. Which of the following consume less electricity? a. Incandescent bulbs b. LED bulbs c. Fluorescent tubes d. CFLs 7. Which mark ensures the safety of the electrical appliance? a. CFL b. MCB c. Trademark d. ISI 118

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Fill in the blanks with appropriate terms: (4 Marks) 2. Draw the symbols of the following circuit components. 1. Our body is a _______________ of electricity. a. Electric cell 2. An electric cell produces electricity from the b. Switch in off position c. Electric bulb _______________ in it. d. Battery 3. In an electric circuit a fuse is a ___________ to prevent possible fire. 4. A combination of two or more cells is called a _________. II. Say whether the following statements are true or false: (5 Marks) 1. Nichrome is used for making fuse wires. 2. Positive terminal of one cell is connected to the negative terminal of another cell in a torch. 3. An electromagnet is a permanent magnet. 4. The wires of a fuse melt when we draw more 3. Draw a simple circuit connecting a bulb current from it. through a wire in the switch on ‘ON’ position. 5. We should not touch an electric switch with wet hands. III. Answer the following: (6 Marks) 1. Name two electric devices for each where (i) heating effect of current is used and (ii) magnetic effect of current is used. 119

15. Light Learning Outcome By the end of this chapter, you will be able to: • Recognize the nature of image formed in concave • Recall that light travels in a straight line. and convex lenses. • Explain reflection of light. • State the properties of image formed in a plane • Infer that sunlight is a white light spectrum made up of seven colours- VIBGYOR. mirror. • Recognize the nature of images formed in concave and convex mirrors. Concept Map Key Points • Light always travels in a straight line and is called rectilinear propagation of light. • When a beam of light falls on a surface it gets reflected. • A plane mirror always forms same-sized image but the image is laterally inverted. • In a concave mirror, the nature of the image varies with the distance of the object from the mirror. It can form real, inverted or virtual and an erect image, • The image formed in a convex mirror is always virtual, erect and diminished. • A convex lens is thick at the middle and thin at the edges. • A concave lens is thin at the middle and thick at the edges. • A convex lens can form virtual and magnified images or real and inverted images that can be of varied sizes. • White light splits into seven colours –VIBGYOR when it passes through a prism. 120

15. Light Work Plan SUBCONCEPT PRACTICE VIDEO/SIMULATION SHEETS Demonstration of reflection of CONCEPT light using torch and mirror. PS – 1 Image of a candle in a plane Spherical mirrors and • Reflection by mirror mirror. images formed by these • Types of images formed PS – 2 Images formed by convex spoon/ mirrors mirror. by these mirrors Images formed by concave spoon/mirror. • Properties of light Images formed by convex lens when an object is placed at Sunlight – White or Dispersion PS – 3 different distances. coloured Newton’s disc PS – 4 Images formed by concave lens PS – 5 when object is placed at different Worksheet for “Light” Self-evaluation distances. sheet Evaluation with self- check or Peer check* 121

PRACTICE SHEET - 1 (PS-1) I. Say whether the statements are true or false: 1. Concave and convex mirrors are plane reflecting surfaces. 2. An image which can be formed on a screen is called a real image. 3. Mirrors are found in spectacles. 4. A convex mirror forms only real images. 5. A convex lens always gives a virtual, erect and diminished image. II. Fill in the blanks with appropriate words: 1. We get diffused reflection from a _______________ surface. (rough/smooth) 2. A smooth polished surface that can return the rays of light incident on it to form a clear image is called a _______________ (lens/mirror) 3. Concave and convex mirrors can both form _______________ (real/virtual) images. 4. A lens is made of a _______________ (translucent/transparent) material. 5. _______________ (white/blue) light consists of many colours. III. Write an example for each of the following: 1. A surface that would give regular reflection. 2. A surface that would act as a mirror. 3. A mirror that always makes things look smaller. PRACTICE SHEET - 2 (PS-2) I. Fill in the blanks: 1. A plane mirror produces _______________ images. 2. A convex lens is also known as _______________ lens. 3. A concave lens is also known as _______________ lens. 4. An image that can be caught on the screen is a _______________ image. 5. _______________ is used as a shaving mirror. II. Complete the following table: TYPES OF IMAGE FORMED PLANE MIRROR CONCAVE MIRROR CONVEX MIRROR Real or virtual Erect or inverted Size of the image 122

PRACTICE SHEET - 3 (PS-3) I. Choose the correct option: 1. When light strikes on the plane mirror a. It reflects b. It scatters in all directions c. It is absorbed by the surface d. None of these. 2. The image formed by a plane mirror is a. Upright b. Virtual c. Same size as the object d. All of the above 3. Which one of the following is used by a dentist to examine the tooth of a patient? a. Concave mirror b. Convex mirror c. Concave lens d. Convex lens. 4. A rear view mirror in the vehicles is a a. Plane mirror b. Convex mirror c. Concave mirror d. Any of the above. 5. A real image can be obtained with a. A plane mirror b. Concave mirror c. Both a and b d. Convex mirror 6. A magnifying glass is a a. Concave mirror b. Convex mirror c. Concave lens d. Convex lens 7. Boojho and Paheli were given one mirror each by their teacher. Boojho found his image to be erect and of the same size whereas Paheli found her image erect and smaller in size. This means that the mirrors of Boojho and Paheli are, respectively a. Plane mirror and concave mirror. b. Concave mirror and convex mirror. c. Plane mirror and convex mirror. d. Convex mirror and plane mirror. 8. Which of the following can be used to form a real image? a. Concave mirror only. b. Plane mirror only. c. Convex mirror only. d. Both concave and convex mirrors. 9. You are provided with a concave mirror, a convex mirror, a concave lens and a convex lens. To obtain an enlarged image of an object you can use either a. Concave mirror or convex mirror. b. Concave mirror or convex lens. c. Concave mirror or concave lens. d. Concave lens or convex lens. 123

PRACTICE SHEET - 3 (PS-3) 10. An erect and enlarged image can be formed by a. Only a convex mirror. b. Only a concave mirror. c. Only a plane mirror. d. Both convex and concave mirrors. 11. You are provided with a convex mirror, a concave mirror, a convex lens and a concave lens. You can get an inverted image from a. Both concave lens and convex lens. b. Both concave mirror and convex mirror. c. Both concave mirror and convex lens. d. Both convex mirror and concave lens. 12. An image formed by a lens is erect. Such an image could be formed by a a. Convex lens provided the image is smaller than the object. b. Concave lens provided the image is smaller than object. c. Concave lens provided the image is larger than object. d. Concave lens provided the image is of the same size. PRACTICE SHEET - 4 (PS-4) I. Choose the correct alternative: 1. State the correct sequence (1-7) of colours in the spectrum formed by the prisms A and B, shown in Fig A B 1 RED 2 ORANGE 3 YELLOW 4 GREEN 5 BLUE 6 INDIGO 7 VIOLET 2. A rainbow can be seen in the sky a. When the sun is in front of you. b. When the sun is behind you. c. When the sun is overhead. d. Only at the time of sun rise. II. Answer each of these questions: 1. An experiment is carried out by passing a narrow beam of white light through a glass prism. i. What would you observe and why? ii. Name a natural phenomenon that is based on this experiment. iii. What would you observe when a newton’s disc is rotated fast? Why? 2. What is a newton’s disc? 3. Which triangular substance is used for dispersing the white light? 124

PRACTICE SHEET - 5 (PS-5) I. Choose the correct option 8. What type of image is formed when an object is too close to a concave mirror? 1. Which of the following are transparent? a. Erect, virtual and enlarged a. Plane mirror b. Erect, real and enlarged b. Concave mirror c. Inverted, virtual and diminished c. Lenses d. Inverted, real and enlarged d. Convex mirror 9. The inner surface of a spoon acts like a 2. The image formed by a plane mirror is at __________ mirror, while its outer surface acts _______ distance from the mirror as the object like a __________ mirror. in front of it. a. convex, concave a. same b. concave, convex b. double the c. concave, concave c. half of the d. convex, convex d. three times the 10. What type of image is formed in a plane mirror? 3. Moon appears to be bright as: a. Sides appear to be interchanged a. It is the source of light b. Erect and virtual image b. It is a glowing object c. Same sized image c. Sun’s light reflects on it d. All of these d. Sun’s light passes through it II. Short answer questions 4. Which of the following colours can never be a 1. Show that light travels in a straight line. colour in rainbow? a. Violet 2. How do you show that the seven rainbow co- b. Black lours combine to give white colour. c. Yellow d. Orange 3. Lenses are useful for us in many ways. Justify the statement. 5. The reflectors of torches, headlights of cars and scooters are _______ in shape III. Long answer questions a. concave 1. Two lenses are given to you. How can you b. convex c. plane identify them as convex and concave lens? What d. All of these happens to the light that is projected on these lenses? 6. Identify the surface that reflects the light among the following. 2. Is the phenomenon called ‘reflection of light’ a. Water useful to us? Justify. b. Polished stone c. Stainless steel plate d. All of these 7. Which of the following is used by dentists to get enlarged image of the teeth? a. Plane mirror b. Concave mirror c. Convex mirror d. Concave lens 125

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. Say whether the following statements are true or false: (4 Marks) 1. Any polished or shining surface can act as a mirror. 2. In a plane mirror, images formed do not show any lateral inversion. 3. Only real images are formed in a convex lens. 4. A rainbow is formed due to dispersion of white light. II. Answer in a sentence or a two: (8 Marks) 1. State any two properties of an image formed by a plane mirror. 2. State a use of a concave mirror and a convex mirror in our daily life. 3. Differentiate between a real image and a virtual image. 4. A shopkeeper wanted to fix a mirror which will give a maximum view of his shop. What type of mirror should he use? Give reason. III. Answer in detail: (3 Marks) 1. You are given three mirrors of different types. How will you identify each one of them? 126

16. Water: A Precious Resource • Explain different ways to manage water. • Analyze one’s role in conserving water. Learning Outcome • State ways to conserve water. • Discuss the effect of water scarcity on plants. By the end of this chapter, you will be able to: • Realize the amount of available water. • Recall forms of water and water cycle. • Recognize the importance of ground water. • State reasons for depletion of water table. Concept Map Key Points • Water exists in solid, liquid and gaseous states. • Water cycle involves evaporation, condensation and precipitation. • Water sources can be divided into two categories: surface water and underground water. • Seasonal monsoons maintain water levels in the Indian sub-continent. • India has a large network of rivers. A large number of dams have been constructed on these rivers to regulate the water flow in these rivers and distribute water more evenly throughout the year. • Water can be conserved by not wasting water in our house hold activities, by recycling water and through rain water harvesting. 127

16. Water: A Precious Resource Work Plan CONCEPT COVERAGE CONCEPT DETAILS PRACTICE SHEET Sources and forms of water • Sources of water PS – 1 • Water cycle • Forms of water Depletion of water and its • Reasons for depletion of water PS – 2 conservation • Methods to conserve water Worksheet for “Water: A Precious Resource” PS – 3 Evaluation with self- check or Peer Self-evaluation Sheet check* 128

PRACTICE SHEET - 1 (PS-1) I. Fill in the blanks with correct words: 1. All the three states of matter are ____________. (reversible/irreversible) 2. Water freezes at _____________. (100°C/0°C) 3. The continuous circulation of water in nature is called __________. (hydrogen cycle/hydrologic cycle) 4. ___________. (Dams/Canals) are built on the rivers to store, regulate water flow and distribute water more evenly. 5. Water levels in rivers increase greatly during ___________. (winter/monsoon) II. Match the definitions to their terms. MEANINGS a. Aquifer TERMS 1. Continuous circulation of water in nature. 2. W ater that is present on the surface of the earth. b. Water cycle/Hydrologic cycle 3. W ater under the ground where soil is completely c. Water table filled or saturated with water. 4. The topmost level of underground water. d. Infiltration 5. W ater reservoir formed above the impervious layers e. Surface water of rock or clay 6. Process of water seeping under the ground. f. Ground water III. Match the following: COLUMN A COLUMN B 1. Ground water a. Water conservation 2. B oiling temperature of water b. Growth in population 3. E conomic use of water c. 100°C 4. Cause of water scarcity d. Drip irrigation 5. Method of watering plants e. Exhaustible renewable resource IV. Say whether the following statements are true or false: 1. Water scarcity is caused when demand and usage of water is more than availability. 2. Rainfall occurs due to precipitation. 3. Surface water is called an aquifer. 4. Rain Water Harvesting involves chemicals to treat rain water. 5. Araveri, Ruparel and Sarsa have been revived by the efforts of social workers. 129

PRACTICE SHEET - 1 (PS-1) V. Complete the following concept map: 130

PRACTICE SHEET - 2 (PS-2) I. Choose the correct option: 1. Water in the industrial sector is used as a. Raw material b. Coolant c. A solvent d. All of the above. 2. In India, water scarcity is predominant in a. North Eastern states b. Tamil Nadu c. Himachal Pradesh d. Thar desert 3. Which one of the following is responsible for the depletion of water table? a. Deforestation b. Agricultural activities c. Increasing population d. All of these 4. Water is a ____________ resource. a. Renewable, exhaustible b. Non renewable, non exhaustible c. Non renewable, recyclable d. Non renewable, non recyclable. 5. The purest form of water is a. Sea water b. Rain water c. Ground water d. Rain water. 6. Which of the following does not show water shortage? a. Taps running dry. b. Long queues for getting water. c. Marches and protests for demand of water. d. A family gets three buckets of water per person per day. 7. Seas and oceans are full of water on earth. However, a very small percentage of water present on earth is available for us. This percentage is roughly a. 0.006%. b. 0.06%. c. 0.6%. d. 6%. 8. Which of the following are not the liquid forms of water? (i) Snow (ii) Lake water (iii) River water (iv) Water vapour (v) Ice Choose the correct combination from the options below. a. (i), (iv) and (v) b. (i) and (ii) c. (ii) and (iii) d. (iii) only 131

PRACTICE SHEET - 2 (PS-2) 9. A man digging the ground near a water body found that the soil was moist. As he kept digging deeper and deeper he reached a level where all the spaces between particles of soil and gaps between rocks were filled with water. The upper limit of this layer is called a. Water level. b. Water table. c. Ground water. d. Water limit. 10. Which of the following is a way to use water economically? a. Construction of bawris b. Rainwater harvesting c. Drip irrigation d. Infiltration 11. On which of the following days is World Water Day observed? a. 22 March b. 14 November c. 2 October d. 21 December 12. Water cycle does not involve which of the following? a. Evaporation b. Condensation c. Formation of clouds d. Rainwater harvesting 13. Which of the following inhibits the seepage of rainwater into ground? a. A pukka floor b. Playground c. Grass lawn d. Forest land II. Answer the following: 1. What is the source of water in each of the following? a. Wells b. Ground c. Atmosphere 2. Fill in the blanks in the given passage. The rainwater and ______a._________ from other sources such as rivers and ponds seeps through the ______b.________ and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called ______c._______. 3. Fill in the blanks and complete the story selecting words from the box given here. cold, demand, leaders, dry, hot, scarcity, workers, wet, oceans, harvesting, rivers Rajasthan is a ___(a)____ and dry place. The challenge of natural ___ (b)____ of water was met by a successful experiment. A band of social ____ (c)____ had transformed a ____ (d)____ area into a green place. They have revived five dried-up ____ (e)____ by constructing water ______ (f)_____ structures. 132

PRACTICE SHEET - 2 (PS-2) 4. Place the following statements in proper order to form a meaningful paragraph. a. Which in turn decreases the seepage of rain water into the ground. b. This decreases the open areas like park and playgrounds. c. Increasing population create demand for construction of houses, shops, offices, roads and pavements. d. This results in depletion of water table and creates scarcity of more water. 5. How can you observe the three forms of water in (i) nature and (ii) at home? 6. Complete the given table FORM OF WATER PROCESS BY WHICH IT IS FORMED LOCATION FOUND a. Liquid Condensation and melting b. Solid Freezing c. Gaseous Evaporation 7. A list of jumbled words are given here. Write the correct form of each word. a. WASHFERRET b. CHARREGE c. QUIFERA d. WOSN 8. From where do the following usually get water? In which form is water present in them? (a) Clouds (b) Plants (c) Mountain tops (d) Aquifer (e) Animals 133

PRACTICE SHEET - 3 (PS-3) I. Choose the correct option 8. Excessive rains cause_________, whereas the absence of rains results in _________. 1. On which day is ‘world water day’ celebrated? a. floods, droughts a. 21st March b. droughts, floods b. 22nd March c. droughts, droughts c. 25th April d. floods, floods d. 30th April 9. Reasons for depletion of water table: 2. In which of the following seasons is the scarcity a. Increase in population of water the most? b. Increasing industrial and agricultural activities a. Rainy c. Scanty rainfall b. Winter d. All of these c. Summer d. Autumn 10. The consequences of water is not available to plants or a world without plants shall mean: 3. Water in which form is found in air around us? a. No food a. Water vapour b. No oxygen b. Liquid c. No rains c. Gaseous d. All of these d. Both (A) and (C) II. Short answer questions 4. What is the percentage of water in sea/ocean? 1. What do you understand by drip irrigation? a. 97% b. 91% 2. Write 3 slogans to convey people about saving c. 2% water. d. 95% 3. Water is a precious resource. Justify. 5. What is infiltration? a. Drawing underground water using hand pumps III. Long answer questions b. Seeping of water into the ground 1. Explain how the increase in population causes c. Filtering water d. All of these depletion of ground water? 6. Deserts have __________ rainfall. 2. Water management should be strong enough to a. Abundant recharge the ground water. Justify. b. Less c. Scanty d. No 7. _________ present in the soil indicates the presence of water underground. a. Moisture b. Animals c. Minerals d. Rocks 134

SELF EVALUATION SHEET Marks: 15 Time: 30 Mins I. State whether the following statements are true or false and if false, write the correct statement: (4 Marks) a. Water vapour is the gaseous form of water. b. Ice is solid whereas snow is the semi-solid form of water. c. Ocean water cannot be used for domestic purposes. d. Rapid growth of industries is one of the causes for water shortage. II. Match the following: (3 Marks) COLUMN A COLUMN B 1. Ground water a. Solid form of water 2. Bawri b. Wastage of water 3. Snow c. Water conservation 4. Drip irrigation d. Small water 5. Leaking taps e. Water table 6. Stopping a leaky f. Water management faucet III.  Answer the following: (8 Marks) 1. State any four ways to conserve water. 2. Explain water cycle briefly. 3. State any four uses of water. 4. What are the factors that deplete water table? 135

17. Forests : Our Lifeline Learning Outcome By the end of this chapter, you will be able to: • Cite examples for autotrophs, heterotrophs and • List the animals found in the forest. decomposers. • List the trees found in the forest. • Define autotrophs, heterotrophs and decomposers. • State the products obtained from forest. • Explain the significance of forest. Concept Map Key Points • Forests are natural resources. • Forests have three major important functions: productive, protective and regulatory • The animals and plants in a forest are linked together through food chain and food web. • Autotrophs are the organisms that prepare their own food. Example: Plants. • Heterotrophs are the organisms that depend on autotrophs directly or indirectly for their food. Example: Camel, lion • Decomposers are the organisms that act on dead and decaying matter, recycling nutrients back to the soil and atmosphere. • Paper, rubber, match, fibre industries are based on forest produce. • Deforestation is caused due to exploitation by human activities. • To conserve forests, preventive measures such as afforestation, planned cultivation, prevention of forest fires and prohibition of killing of animals, felling of trees should be adopted. 136

17. Forests : Our Lifeline Work Plan CONCEPT SUB CONCEPT PRACTICE SHEET Some forest plants and • Importance of forest PS – 1 animals • Forest as habitat • Some common animals and plants of forest • Types of forest trees (crown, canopy and understory) Interrelationship of plant, • Autotrophs, heterotrophs and saprophytes in forests soil and decomposers in • Importance of decomposers in forest PS – 2 a forest • Importance of forest Worksheet for “Forests : Our Lifeline” PS – 3 Evaluation with self- Self-evaluation Sheet check or Peer check* * Administering self-evaluation at the end of a chapter is a good practice • Teacher discusses the correct answer or displays it using an overhead projector and asks the students to exchange their sheets or books to check and correct each other’s work. • The teacher may only need to do a sample check of students’ work. • Typically takes 10 – 15 mins. 137

PRACTICE SHEET - 1 (PS-1) I. Give two examples for each of the following: 1. Industries dependent on the forests. 2. Trees. 3. Animals. 4. Heterotrophs. 5. Decomposers. II. State whether the following statements are true or false: 1. Xerophytic scrubs are found in tropical forests. 2. Producers feed on animals. III. Select the appropriate term from the box for the following descriptions: Canopy Crown Deforestation Topography Heterotrophs 1. Organisms that depend on producers directly or indirectly. 2. Physical feature of a place. 3. Upper most layer of a forest. 4. Layer from which trees branch off from the tree trunk. 5. Act of destroying the forests by cutting down the trees. II. Answer the following Questions: 1. Why did the monkeys disturb the birds on seeing human beings? 2. Name the products obtained from the forest. 3. What are the different layers of the forest. 4. Form a food chain: frog, eagle, plant, insect, snake 138