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18.Waste, Answer Orally( Pg.No-246), 1. Define the following:c) Biodegradable waste:- The waste that undergo degradation or rot and are broken down to harmless, or non-poisonous substances., Ex- Dead plants & animals, Vegetable & fruit peels etc., d) Non-biodegradable waste:- The waste which cannot be broken down by decomposers., Ex- Glass, Plastic items, metals etc., g) Composting:- The conversion of solid waste into manure., h) Vermicomposting:- The method of preparing compost with the help of earthworms., Answer in Detail:Q.2) Differentiate between landfills and compost pits?, Ans., , Compost Pits, It is a simple method of recycling, biodegradable waste into manure in, pits., The rate of degradation of, biodegradable waste is fast., , Landfills, It is a method of managing organic waste, in large open areas. Recycling of, biodegradable waste does not happen., The rate of degradation of biodegradable, waste is very slow., , Q.5) What can be done to minimize the use of plastics?, Ans. Some of the steps to reduce the use of Plastics arei) Carry a Cloth or Jute bag whenever go for shopping., ii) Say No to plastic bag instead use paper bags., iii) Do not use plastic bags for storing food items., iv) Organize awareness campaigns through schools, television & radio., v) Do not throw or burn plastic items and try to reuse as much as possible., Answer Briefly:Q.6) Name the three R’s that help us to manage the wastes properly?, Ans. The 3 Rs of managing wastes are:, (a) Reduce: We can reduce the amount of waste generated by consuming more and throwing away, less., (b) Reuse: We can reuse certain things for more than one purpose., (c) Recycle: We can recycle waste materials to make new products.

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17.Importance of Air, Answer Orally ( Pg.No-230), Q.2) What is atmosphere?, Ans. The thick blanket of air that envelops the earth completely. This covering of air is called, atmosphere., Answer Orally ( Pg.No-235), Q.4) why do mountaineers carry oxygen cylinders along with them when they climb high mountains?, Ans. With increase in altitude, the atmosphere gets thinner & supply of oxygen is reduced. This causes, difficulty in breathing. Therefore while climbing mountains, mountaineers carry oxygen cylinders with, them., Answer Briefly:Q.3) Why do sea divers carry oxygen cylinders when they go deep in the sea?, Ans. Sea divers carry oxygen gas cylinders along with them because there is no free oxygen in the sea, water. since the little dissolved oxygen present in water can't be used for breathing by divers., , 16.Importance of Water, Answer Orally ( Pg.No-223), 1) Define Drought & Flood?, Ans. Drought:- Drought occurs when an area does not receive rainfall for a period of a year or more., Due to this, soil continues to lose water by evaporation and transpiration and becomes dry and infertile., Flood :- The condition during which rain water being everywhere, even submerging the land is, called as flood. Floods are caused by rise in the water level in ponds and lakes due to heavy rainfall., 3) What is rooftop rainwater harvesting?, Ans. It is a technique of collecting rainwater from rooftop with the help of network of pipes and stored, in a storage tank, from storage tank water seeps in the ground or used after cleaning., Answer in Detail:Q.6) what is rainwater harvesting? How is it done?, , Ans. Rain water harvesting is the process of collecting the rain water which used to run off from the, roof tops, parks, roads, and tanks.

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This collected water is used to store for future purpose. Also it is recharged to the ground, water to reuse the water. Instead of letting the rainwater to run off and go waste, it is stored and used, for future purpose., Answer Briefly:Q.2) What is Water table?, Answer- The level of water under the ground., Q.6) How does soil gets affected due to, a) scarcity b) excess of water ?, Ans. a) Due to scarcity of water, soil dries up completely, becomes hard and begins to crack and, gradually become infertile and the whole vegetation of affected area is lost., b) Due to excess water, it washes the top layer of the soil and makes the soil infertile and also due to, accumulation of water in fields, destroys the crop production., , 15. Light, Answer Orally ( Pg.No-206), 3) What is Shadow?, Ans. A dark shape produced when an object comes between a source of light & a surface., Pg.No- 208, Q. Why is “AMBULANCE” written as “ECNALUBMA” in vehicles used to transport patients?, Ans. The word AMBULANCE is written laterally inverted in front of the ambulance because when seen in, the rearview mirror of our vehicle, the image of the word would get inverted and can be read easily and, provide way to the ambulance., Answer Orally ( Pg.No-209), 4) What is reflection ?, Ans. The phenomenon of bouncing back of light from the surface of an object is called reflection., Ex- Glass, polished surface etc., Answer in Detail:Q.5) Give four characteristics of shadow?, Ans. Four characteristics of shadow are:i) It is always either large or same size as that of the object., ii) Its position changes depending upon the position of source of light., iii) it needs a screen for being formed., iv) It always black in color

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Q.1) Differentiate between opaque, translucent and transparent objects. Give two examples of each., Ans. 1. Transparent objects - Those objects through which light can pass easily are called transparent object, Ex- Water, Glass, Air etc., 2. Translucent object - The object through which light can pass partially are called translucent objects, Ex- Tracing paper, waxed paper etc., 3. Opaque object - The objects which do not allow the light to pass through are called opaque objects,, Ex- Wood, Metals etc., Q.7) Give differences between the shadow and the image of an object in a mirror?, Ans., Shadow, , Image, , 1. Shadow is formed by obstruction of, light, , 1. Image is a true reflection of an object, , 2. Shadow is a region of the absence of light, , 2. Image is formed by light rays., , 3. Shadow provides only a rough outline of an, object as the shadow is only a dark patch, formed on a surface., , 3. Image of an object provides all the details of the, object like shape and colors., , 4. Shadow can be seen only on the surface, , 4. Image formed by a plane mirror cannot be seen on, a screen., , 5. Size of the shadow can be changed by, changing the position of the object & source, of light., , 5. Size of image in a plane mirror is always the same, as that of the object., , Answer Briefly:Q.4) What are the three necessary conditions to form a shadow?, Ans. Conditions required for a shadow to form are:, i) There should be a source of light., ii) An opaque object., iii) A screen.

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14.Rain,Thunder & Lightning., Answer Orally ( Pg.No-195), 1) What is precipitation?, Ans. The process of water drops coming back on the earth inn the form of rain, hail or snow., Answer in Detail:1) How is evaporation is different from boiling?, Ans., Evaporation, , Boiling, , Evaporation is a process that occurs when the, liquid changes into the gaseous form., , Boiling is a process where the liquid gets heated, up and vaporized due to continuous heating of the, liquid., , Evaporation usually occurs on the surface of, the liquid being heated up., , Boiling usually occurs on the entire mass of the, liquid that gets heated up., , Bubbling effect is not visible in evaporation., , Bubbling effect is visible during the process of, boiling., , The process of evaporation is usually slower, and more carried out when compared to, boiling., , The process of boiling is usually much quicker, and the process happens quite rapidly as well., , 3) What is water cycle?, Ans. The continuous circulation of water among land, water bodies and atmosphere., , 13.Magnets, Pg.No-183, 1) Define magnetic induction?, Ans. The process of magnetizing an unmagnetized iron piece by repeatedly bringing a magnet closer to, it., Answer Briefly:2) Give two fundamental properties of magnets?, Ans- Two properties of a magnet are:, (i) A magnet always has two poles: a north pole and south pole., (ii) Like magnetic poles repel each other and unlike magnetic poles attract each other.

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4) What are magnetic substances? Give examples., Ans- The materials that are easily attracted by a magnet., Ex- Iron, Nickle, Steel etc., 5) What are non-magnetic substances? Give examples., Ans- The materials that are not attracted by a magnet., Ex- Stainless steel etc., 7) Why do magnets align themselves in the north-south direction?, Ans- The magnets align themselves in the north-south direction due to earth’s magnetic field which, attract it., , 12. Electric Current & Circuit, Answer Orally ( Pg.No-164), 3) Name essential parts of an electric bulb?, Ans- The essential part of an electric bulb are, a) Filament b) Metal Casing, , c) Glass case, , d) Inert gas ( nitrogen,argon etc.), , Answer Orally ( Pg.No-169), 1) Define an electric circuit?, Ans- The setup consisting of the source of electricity, such as an electric cell, the electric bulb, and, electric wires joint together in such a way that the electric current can flow along a closed loop., 2) What is fused bulb?, Ans- It is said that a bulb is fused if the filament is broken. When the filament of the bulb gets broken,, then no electric current will pass through it and the bulb is said to be fused., 3) What is advantage of using an electric switch in an electric circuit?, Ans- A switch in an electric circuit provide us the choice to on/off that appliance according to our choice, and other benefit is that if an appliance is not working properly then by switching off we can reduce the, chances of electrical short circuit., Answer in Detail:1) Give the function of each of the essential parts of the electric circuit., Ans- The four essential components of an electric circuit are, Electric cell :- An electric cell provides electricity to the devices connected in the circuit.

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Electric bulb :- An electric bulb is the device (or load) in the circuit. It glows when the electric, current, flows in the circuit., Switch :- An electric switch is a device used to break or complete the circuit at will., Connecting wires :- The connecting wires are conductors which are used to connect the components of, the circuit to form a circuit., Answer Briefly:3) Define electric current., Ans- A form of energy i.e. electrical energy which gets converted into heat and light energy, when it, flows through an electric bulb., 8) Why electric wires made up of metals?, Ans- Electric wires made up of metals because metallic wires are good conductors of electricity., 9) Why electric wires covered with plastics?, Ans- Electric Wires are covered with plastic because of the following reasons:, a) Plastic is a good insulator it does not allow current or heat to flow through it., b) Plastic ensures that the current flows only in the wire and not outside the wire., c) Plastic reduces the chances of getting shocked., , 10. Animals-Form & Function, Answer Orally ( Pg.No-140), 1c) Define Ligaments?, Ans- The strong structures which hold the bones together at the joints., , Answer in Detail:2) What are the main functions of the skeletal system?, Ans- The skeletal system perform the following jobs or functions:i) It provide shape to the body., ii) It provide a framework which supports the body & keeps it upright., iii) It protects the soft internal organs like heart, stomach & liver., iv) Blood cells are made in the soft substances (bone marrow) present in the bones which form the, skeleton.

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3) Name & describe the three main types of joints found in your body. Give two examples of each, type., Ans- i) Immovable Joints:- These joints do not allow any movements., Ex- a) Joints between the bones of skull, b) Joints in the tooth socket, ii) Slightly movable joints:- These joints allow very little movement., Ex- a) Joints between adjacent vertebrae in the backbone, b) Joints between the ribs and the breastbone, iii) Free movable joints:- These joints allow free movements of bones in various directions., Ex- a) Joints in the elbow, b) Joints in the knee, There are four major types free movable joints:, a) Ball & socket joint, c) Hinge joint, b) Pivot joint, d) Gliding joint, , 9. Plants-Form & Function, Answer in Detail:2) Give differences between the following:, a) Roots & stem, Roots, , Stem, , Roots are the non green underground parts of a, plant, Roots take in water and minerals from the soil, , Stems are the main axis of shoot system which, bears the branches , leaves , flowers , buds etc, It helps to keep the plant upright, , Roots fix the plants to the soil, , The stem transports water and minerals from the, roots to the leaves., Stem helps in respiration through stomata or, lenticels., , Roots help in respiration through general surface, area., , b) Herb and Shrub, Herb, , Shrub, , Small plants with tender green stems., , Medium sized plants with hard stems, , Branches are not present in herbs, , These arise near the base of the plants, , Examples are coriander, Mustard etc, , Examples are Rose, China rose etc

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c) Node and Internode, Node, , Internode, , The place from where the branches and leaves, arise on the stem is called node, It contain an axillary bud, , The portion of the stem between two nodes is, called internodes, It does not contain an axillary bud, , It Bear buds which can convert into branches ,, flowers or cones., , It is responsible for increasing the length of stem., , d) Creepers and Climbers, Creepers, , Climbers, , Plants that cannot stands upright and spread on, the ground are called Creeper, Creepers are very weak plants, , Plants which climb up with the support of, neighboring structures are called Climbers, Climbers are weak plants, , Examples are Mint , Gourd plants, , Examples are Money plants , Pea Plants, , e) Reticulate venation & parallel venation., Reticulate venation, , Parallel venation, , In reticulate venation, veins are arranged in a netlike pattern on both side of the mid-rib., , In parallel venation veins run parallel to one, another., , Ex- Petunia, pea, rose etc., , Ex- Grasses, banana, palms etc., , f) Stamen and Pistil, Stamen, , Pistil, , Male reproductive part of the flower consisting of, containing anther and filament., , Female reproductive organ of a flower consisting, of stigma , style and ovary, , Stamen occurs outside the pistil., , Pistil occur at the center of the flower, , It produce Pollen grains., , It produces ovules., , 3) List the function of various parts of flower?, Ans- A flower shows four sets of parts arranged in rings or whorls :a) Petals: This is a bright-coloured part that attracts bees, insects, and birds. Colour of petals varies from, plant to plant; some are bright while some are pale coloured. Thus, petals help us to differentiate one, flower from another.

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b) Sepals: Sepal is the green-coloured part beneath the petals to protect rising buds. Some flowers have, fused petals-sepals while a few have separated petals-sepals., c) Stamen: This is the male reproductive organ and is also known as Androecium. It consists of two parts, namely: anther and filaments., 1. The anther is a yellowish, sac-like structure, involved in producing and storing the pollens., 2. The filament is a slender, threadlike object, which functions by supporting the anther., d) Pistil: This is the innermost part and the female reproductive organ of a flower which comprises three, parts -stigma, style and ovary. This is collectively known as the pistil., 1. Stigma: It is the topmost part or receptive tip of carpels in the gynoecium of a flower., 2. Style: It is the long tube-like slender stalk that connects stigma and the ovary., 3. Ovary: It is the ductless reproductive gland that holds a lot of ovules. It is the part of the plant, where the seed formation takes place.