1 FOOD : WHERE DOES IT COME FROM

P-1FOOD : WHERE DOES IT COME FROM

Ans. 1. We require energy to perform different activities. This energy is obtained from the food we eat which is oxidized in the cells to release energy.

Ans. 2. Two ingredients are needed to prepare a dish of boiled rice. They are rice and water.

Ans. 3. Manybees live inabeehive.Thesebeescollectsweet juices (nectar) fromflowers.They convert the nectar into honey and store it into the hive.

Ans. 4. The animals that feed on both plants and animals are called omnivores. E.g. Humans, Crow.

Ans. 5. The main sources of our food are plants and animals. The food items which we get from animals are milk, eggs and chicken.

Ans. 6. Sproutedseedsaretheseedswithseedlings.Seedsarefirstsoakedinwaterforoneday. The water is drained and the seeds are kept wrapped in a wet cloth and left for one more day. After sprouting, they can be eaten raw. They can also be boiled. It can also be made into a tasty snack by adding spices into it.

Ans. 7. Food is obtained from both plants and animals. Fats obtained from animals are ghee and cod (fish) liver oil.Mustard oil and groundnut oil are the fats obtained fromplants.

Ans. 8. (a) Milk contains a lot of proteins and some amount of fat. Milk is a rich source of minerals like phosphorus and calcium which are required for making the bones strong. It is known as an energy drink the helps to build up muscles and bones.

(b) The four milk products used in our daily diet are curd, cheese, butter and ghee.

(c) The materials required to make a food item are known as ingredients.

SUMMATIVE ASSESSMENT WORKSHEET-2Ans. 1. Paddy and wheat.

Ans. 2. No, it is available only for a part of the year.

Ans. 3. Different food items contain different types of nutrients in them. Thus, by eating more than one dish in a single meal, we get more nutrients for our body.

Ans. 4. Beescollectnectarfromflowersandconvertitintohoney.Thehoneyisstoredinthebeehives to be used throughout the year.

Ans. 5. Edible part of Oinion : underground stem (bulb), Brinjal : fruit, Tea : leaves.

Ans. 6. Photosynthesis is the process by which green plants prepare their food. In this process, green plants trap sunlight with the help of the chlorophyll present in them and synthesize the sugar known as glucose from carbon dioxide and water. In this process, oxygen is given out from plants as a by-product.

Ans. 7. Sprouts are obtained by keeping water soaked seeds in a vessel covered with a wet cloth overnight. On availability of adequate moisture, the seeds of plants geminate to give out a small white structure. At this stage, the seed is said to be sprouted.

SUMMATIVE ASSESSMENT WORKSHEET-1

1 FOOD : WHERE DOES IT COME FROM

P-2 SCIENCE – VI

Sproutedseedsarerichinproteins,vitaminsandminerals.So,theyarebeneficialforhealth.

Ans. 8. The functions of food are as follows : (a) It helps in the growth and development of a living organism. (b) It provides energy to do physical work. (c) It is needed for replacement and repairing of damaged body parts. (d) It gives us resistance against diseases and protects us from infections. (e) It helps to provide energy to perform body functions like breathing and

circulations.


[A] Multiple Choice Type Questions :

1. (a) 2. (d) 3. (c) 4. (c) 5. (b)

[B] Fill in the blanks :

1. Sprouts

2. Nectar and honey

3. Omnivores

4. Sugarcane

5. Carnivore

6. Plant

[C] Define:

1. Plant eating animals are called herbivores.

2. Flesh eating animals are called carnivores.

3. Animalsthateatbothplantsandfleshofanimalsarecalledomnivores.

4. The material which is required to prepare a dish is called ingredient.

[D] 1. Cat - milk, small animals.

2. Spider - insects.

3. Houselizard - insects.

4. Buffalo - oil cake, grass

5. Rat - grains.

P-3FOOD : WHERE DOES IT COME FROM

FORMATIVE ASSESSMENT WORKSHEET-4


1. (b) 2. (b) 3. (c) 4. (a) 5. (d)

[B] Write true or false :

1. True

2. False

3. False

4. True

5. False

[C] Flower, leaf, bud, stem, root.

[D] Complete the table :

1. Tomato - fruit

2. Carrot - root

3. Turmeric - underground stem

4. Sugarcane - stem

5. Peas - seed

6. Spinach - leaf

7. Brinjal - fruit

8. Mint - leaf.

P-4 SCIENCE – VI

Ans. 1. Soft and bent bones.Ans. 2. By eating a balanced diet.Ans. 3. Thediscasescausedbythedeficiencyoffollowingare: 1. Iron:DeficiencycausesAnaemia. 2. VitaminA:Deficiencycausesnightblindness. 3. VitaminB:DeficiencycausesBeri-Beri. 4. VitaminC:DeficiencycausesScurvy.Ans. 4. Vitamins andminerals are called protective foods. They protect our body against

diseases.Ans. 5. Vitaminsarecomplexorganiccompounds,whichareessentialforthegrowthofour

body.Theydonotprovideenergy. VitaminAkeepsourskinandeyeshealthy. VitaminChelpsthebodytofightagainstdiseases.Ans. 6. (a) Carbohydrates are the compounds made up of carbon, hydrogen and oxygen.

Theseareformedinplantsduringphotosynthesis.e.g.Glucose. (b) Carbohydratesfoundinourbodyareintheformofstarchandsugar.Ans. 7. (a) Junkfoodmakesthepersonobese. (b) Hemaysufferfromlossofappetite. (c) Hemaydeveloptheproblemsrelatedtohis/herphysicalormentalgrowth. (d) Itleadstowastageofmoney.

Ans. 8. Takeasmallquantityoffooditeminatesttube.Add10dropsofwaterintoitandshakethetest tube.Withthehelpofadropper,addtwodropsofcoppersulphatesolutionandtendropsofcausticsodasolutiontothetesttube.Shakethetesttubeand let it stand for a fewminutes. The appearance of violet colour indicates thepresenceofproteinsinthefooditem.

Ans. 1. Glucose directly enters the bold stream and produces energy through respirationimmediately.Hence,itactsasasourceofinstantenrergy.

Ans. 2. 1.Carbohydrates,2.Fats.Ans. 3. Takeasmallquantityoffooditemandput2-3dropsofdiluteiodinesolutiontoit.If

itturnsblueorblackincolour,itindicatesthepresenceofstarchinthefooditem.

Ans. 4. Eating toomuchof fat rich food is the reason for obesity.Fried food like samosa,poori,malaiandgheecauseobesity.

Ans. 5. Themajornutrientsinourfoodneededforthegrowthofourbodyarecarbohydrates,proteins,fats,vitamins,minerals,fibersandwater.

Ans. 6. (a) Ourbodyneedsallthenutrientsinrightamount.Henceweshouldeatabalanced diet.

(b) Carbohydratesfoundinourfoodareintheformofstarchandglucose.


2 COMPONENTS OF FOOD


P-5COMPONENTS OF FOOD

Ans. 7. Dietaryfibersarealsoknownasroughage.Roughage ismainlyprovidedbyplantproducts inour food.Wholegrains,pulses,potatoes, fruitsandvegetablesare themainsourcesofroughage.Roughagedoesnotprovideanynutrienttoourbody.Butitisessentialcomponentofourfoodasithelpsourbodytogetridofundigestedfood.

Ans. 8. (a)Weneedwaterinourfoodbecause:

1.Ithelpsinabsorptionofthenutrientsinthebody.

2.Ithelpsinremovalofthewasteproducts.

(b) Vegetablescontainvitaminsandmineralswhichgetwashedaway,ifvegetables are washed after cutting them.Hence vegetables should not be washed after cutting.Foodshouldnotbeovercookedtopreventthelossofnutrientsfromit.



1. (c) 2. (d) 3. (a) 4. (b) 5. (a)


1.True

2.True

3.False

[C] Four sources of carbohydrates :

Sugarcane,Potato,Wheat,Maize,Bajra,Papaya(Any4).

[D] Match the column :

Column (A) Column (B)

VitaminA LossofVision

VitaminB Beri-Beri

VitaminC Scurvy

VitaminD Rickets

Iodine Goitre

Calcium Boneandtoothdecay

Iron Anaemia

[E] Sources of vitamins :\

Vitamin A Vitamin B Vitamin C Vitamin D1.Milk2.Fishoil3.Papaya

1.Liver2.Grains3.Rice

1.Orange2.Tomato3.Guava

1.Milk2.Butter3.Fish

P-6 SCIENCE – VI



1. (b) 2. (a) 3. (c) 4. (a) 5. (b)


1. Nutrients

2. Carbohydrates

3. Fats

4. Proteins

5. Balanced diet

6. Deficiencydiseases.

[C] Answer the following :

1. Obesityisaconditionthatarisesduetoeatingtoomuchfoodrichinfats.

2. Roughageisacomponentoffoodthataddsbulktofoodandhelpsthebodytoget ridofundigestedfood.

3. Adietrichinallnutrientsiscalledbalanceddiet.

[D] Animal and plant sources of fats :

Animals Source1.Milk2.Meat3.Fish4. Eggs5.Butter

Plants Source1.Groundnuts2.Coconutoil3. Nuts4.Sunfloweroil5. Til

[E] Symptoms of Scurvy and Rickets :

ScurvyBleedinggums,woundstakelongertimetoheal.

RicketsBonesbecomessoftandbent.

P-7FIBRE TO FABRIC

Ans. 1. Theprocessofremovingseedsfromcottonfibersiscalledginning.

Ans. 2. Juteplantsareusuallyharvestedatfloweringstage.

Ans. 3. 1. Coconutfibersareroughandveryhard.Thuscanbeusedformakingropes.

2. Coconutfibersareusedformakingmattresses.

Ans. 4. (a) Theprocessofarrangingtwosetsofyarnstogethertomakeafabricisknownas weaving.

(b) Weavingisdoneonloomswhichareeitherhandoperatedorpoweroperated.

Ans. 5. Man-madefibersarecalledsyntheicfiberse.g.,Nylon,Rayon,Polysteretc.

Ans. 6. Theprocessofmakingyarnfromfibersiscalledspinning.Inthisprocess,fibersfromamassofcottonorwoolaredrawnoutandtwisted.Thisbringsthefiberstogethertoformayarn.Deviceswhichareusedforspinningarespindleandcharkha.

Ans. 7. Fibersobtainedfromplantsandanimalsareknownasnaturalfibers.Cotton,juteandcocountareexamplesofplantfibers.Silkandwoolareexamplesofanimalfibers.

Ans. 8. 1. Weavingandknitting.

2. Spinning.

3. CottonandJute.

Ans. 1. Asingleyarnisusedforknitting.

Ans. 2. Cottonisacellulosefiber.

Ans. 3. Sareeisusedasanun-stitchedpieceoffabric.

Ans. 4. Twohandoperateddevicesare:Handspindle(takli),Charkha.

CharkhawasmadepopularbyMahatmaGandhi.

Ans. 5. (a) JuteiscultivatedinWestBengal,BiharandAssam.

(b) Itiscultivatedduringrainyseason.

Ans. 6. (a) Cottonballsarethefruitofcottonplant.

(b) Thesoilbestsuitedforthegrowthofcottonplantisblacksoil.

(c) Ginningistheprocessinwhichseedareseparatedbycombing.

Ans. 7. 1. Syntheticfibersarestrongsotheycantakeupheavyloads.

2. Theyhavegothightensilestrength,whichenablesthemtocarryweights.

3. Theyeasilyretaintheiroriginalshape,even if theygetwrinkled.So theyare convenienttowashandwear.

4. Theyhavegrateelasticityduetowhichtheycanbeeasilystretched.


3 FIBRE TO FABRIC


P-8 SCIENCE – VI

Ans. 8. Natural fibers : Wool and Jute.Wool is an animal fiberwhich is obtained fromsilkwormandjuteisaplantfiberobtainedfromplant.

Synthetic fibers : Acrylic,Polyesterandrayon.Theseareman-madefibersandarepreparedfromdifferentchemicalsubstances.



1.(d)2.(c)3.(c)4.(b)5.(c)


1.Ropes,mattresses

2.Synthetic

3.Looms

4.Jute

5.Wool,silkfibers

6.Cotton,jute

7.RiverNile.

[C] Define the following :

1. Fibersaresubstancesthatareusedtomakeyarnsandfabrics.

2. Naturalfibers occur innature andare obtained fromplants andanimals. e.g. Cotton,Wooletc.

3. Syntheticfibersarepreparedartificially.e.g.Polyester,Nylon.

4. Ginningistheprocessofseparatingseedsfromthefibers.

5. Spinningistheprocessofmakingyarnsfromthefibers.

P-9FIBRE TO FABRIC

FORMATIVE ASSESSMENT WORKSHEET-12[A] Multiple Choice Type Questions :

1.(c)2.(a)3.(b)4.(b)5.(b)

[B] Name the following :

1. Knitting 2.Cottonboll 3.Spinning

4. Handloom 5.Weaving

[C] Give examples :

1. 2 natural fibers : CottonandJute

2. 2 synthetic fibers : NylonandPolyester

[D] Match the following :

1. Plantfiber-jute

2. Animalfiber-silk

3. Makingyarn-spinning

4. Separationofseedsbycombing-ginning

5. Arranging2setsofyarns-weaving

6. Syntheticfiber-nylon.

P-10 SCIENCE – VI

Ans. 1. Wood and paper.

Ans. 2. We need to group materials for convenience and to gain systematic knowledge.

Ans. 3. Theobjectswhichcanfloatinwaterare:Driedleavesandwood.

Theobjectswhichsinkinwaterare:Apieceofironandstone.

Ans. 4. Soluble materials : Salt and Sugar.

Insoluble materials : Sand and Chalk.

Ans. 5. The materials through which objects are only partially visible are known as translucent materials. e.g. butter paper.

Ans. 6. Hardness is the property of materials that can be found out by pressing the material. Amaterialmaybesoftorhard.

Soft materials : The materials which can be compressed easily are known as soft materials. eg. Cotton, Sponge etc.

Hard materials : Thematerialsthataredifficulttocompressareknownashardmaterials. eg. iron, wood etc.

Ans. 7. Materialscanbeclassifiedintothreegroupsonthebasisofphysicalstates:

Solids : Theyhavedefiniteshapeandvolumee.g.,iron,iceetc.

Liquids : Theyhavedefinitevolumebutdonothavedefiniteshapewater.

Gases : Theydonothavedefiniteshapeandvolume.e.g.air.

Ans. 8. (a)Transparent materials Opague materials

The materials or substances through which things can be seen.

e.g., glass, water

The materials through which things cannot be seen.

e.g., wood, cardboard.

(b) We can make a normal paper translucent by putting few drops of oil on it.

(c) Shopkeepers keep eatables like biscuits, sweets etc. in transparent containers so that buyers can easily see these items.


4 SORTING MATERIALS INTO GROUPS

P-11SORTING MATERIALS INTO GROUPS


Ans. 1. Materials are grouped together on the basis of similarities and differences in their properties.

Ans. 2. Woodislighterthanwater.Therefore,itfloatsonwater.

Ans. 3. Materialswhicharelighterthanwaterfloatonwater.Woodandoilarelighterthanwaterfloatonit.

Ans. 4. (a) It helps in gaining systematic knowledge of things.

(b) It gives a general idea about all members of a group and the differences between members of different groups.

Ans. 5. No, torch light does not pass through the palm because our palm is opaque.

Ans. 6. (a) Books can be sorted into groups on the basis of class and subject.

(b) Clothes can be sorted into groups on the basis of size and colour.

(c) Utensils can be sorted into groups on the basis of utility and material used in making them.

Ans. 7. The materials which have shining surface are called lustrous materials. Gold and silver are examples of lustrous materials.

Ans. 8. (a) Appearance :Appearanceofamaterialsiscomparedintermsofcolour,luster, textureorphysicalstate.Ametalspoonshineswhereasawoodenspoondoesnot shine.

(b) Hardness : Soft materials : The materials than can be compressed easily or scratched easily are soft. e.g. cotton, sponge.

Hard materials : The materials that cannot be compressed or scratched easily are called hard. e.g. iron.

(c) Solubility : Substances that disappear or dissolve completely in water are called soluble substances. e.g. salt, sugar etc.

(d) Transparency : Transparent materials : Substances through which things can easily be seen are transparent materials. e.g. glass, water.

Opaque materials : Substances through which nothing can be seen are opaque materials. e.g. wood.

Translucent materials : Substances through which objects can be seen but not clearly are translucent materials. e.g. butter paper.

(e) Floating property :Anobjectswillfloatorsinkinwaterdependsonwhether itislighterorheavierthanwater.Materialslighterthanwaterwillfloat,e.g. plastic, and materials heavier than water will sink in water, e.g. iron nail.

P-12 SCIENCE – VI



1. (a) 2. (c) 3. (a) 4. (c) 5. (a)


1. Sugar, 2. Pencil, 3. Sand, 4. Silver, 5. Sand paper.

[C] Match the following :

1. Soft materials

2. Hard materials

3. Soluble

4. Translucent

5. Lustrous

6. Wool.

[D] Mention the objects against each shape :

1. Plate, chapati

2. Pencil box, book

3. Television, window.



1. (c) 2. (d) 3. (a) 4. (d) 5. (a)


1. Soft, 2. Hard, 3. Luster, 4. Glass, 5. Sand, 6. Book and wood.


1. Transparent materials : Substances through which things can be seen easily are called transparent objects. e.g. glass.

2. Opaque materials : Substances through which objects cannot be seen are called opaque materials. e.g. wood.

3. Translucent materials : The materials through which objects can be seen but not clearly are known as translucent materials. e.g. butter paper.

4. Salt, sugar and alcohol.

5. Wood, dry leaves and ice.

[D] 5objectsmadefromplasticare:Pen,Pencilbox,Containers,Bottles,Plates.

P-13SEPERATION OF SUBSTANCES

Ans. 1. The process of conversion of water vapor into its liquid form is called condensation.

Ans. 2. The process of settling down of solid particles quickly by addition of alum is called loading.

Ans. 3. A saturated solution of a substance is the one in which no more of that substance can be dissolved.

Ans. 4. The process of conversion of water into its vapour form is called evaporation. It takes place at all temperature. For example, when sea water is allowed to stand in shallow pits, water slowly turns into water vapors by absorbing the heat of the sun, leaving behind the solid salts.

Ans. 5. Decantation is a method of separation, when two components do not mix with each other. When the insoluble solute particles settle down, the liquid is poured into another container.

Ans. 6. Sieving is a method used for separating solid components of mixtures varying in size. Sieving allows the fine particles to pass through the holes of the sieve while the bigger particles remain on the sieve. It is used to separate pebbles and stones form the sand.

Ans. 7. Sea water is allowed to stand in shallow pits. Due to solar heat, water in the pits gets heated and it slowly converts into vapours by evaporation. After some days, the water evaporates completely and the solid salts remain in the pits. The salts of the pits are further purified to get pure common salts.

Ans. 8. We can extract clear water from muddy water by loading and decantation processes. The muddy water is taken in a beaker. Alum is tied with a thread and is suspended in the muddy water. The alum piece is moved slowly in circular path in the muddy water for some time. The alum is removed and the beaker is kept undisturbed for some time. Alum dissolves in water easily. The fine dust particles, which are responsible for making the water muddy, settle down readily as they get loaded with the alum particles and form larger aggregates. The process is called loading. The clear water is decanted in another beaker.

Decantation

Clear water

Clay

particles

Loading

Muddy

waterAlum Fine particles

of clay settle

down faster


5 SEPERATION OF SUBSTANCES

P-14 SCIENCE – VI


Ans. 1. By distillation process.

Ans. 2. Centrifugation is a process of separating suspended solid articles from a liquid.

Ans. 3. A pure substance is a single substance of a definite composition. It contains particles of only one type. E.g. pure copper and pure water.

Ans. 4. When a mixture is allowed to stand for some time, the heavier component in mixture settle at the bottom and the process is called sedimentation. For example, when mixture of sand and water is allowed to stand for some time, the particles of sand settle down at the bottom of vessel.

Ans. 5. (a) The constituents of a mixture may be in any ratio.

(b) The constituents can be separated by simple methods.

Ans. 6. (a) Winnowing is a method of separation which is used to separate heavier and lighter components of mixture by wind or by blowing air.

(b) Difference in weights of the constituents lead to their separation by winnowing.

Ans. 7. We need to separate different components of a mixture for the following reasons :

To remove useless components e.g., tea leaves after making tea.

To separate two different but useful components e.g., churning milk to obtain butter.

To remove impurities e.g., obtaining salt from water.

Ans. 8. Sugar can be separated from the mixture of wheat flour and sugar by sieving process. The mixture is poured on a sieve. The fine particles of wheat flour pass through the

holes of the sieve and the sugar particles being bigger in size remain on the sieve. In

this manner, sugar can be separated from the mixture of wheat flour and sugar.


1. (a) 2. (c) 3. (a) 4. (b) 5. (c)


1. Handpicking

2. Winnowing

3. Sedimentation

4. Miscible substance

5. Solution.

[C] Match them :

1. Used to separate heavy and light solid particles.

2. Used to separate particles of different sizes.


P-15SEPERATION OF SUBSTANCES



1. (a) 2. (d) 3. (c) 4. (a) 5. (c)

[B] Coin one word for the following :

1. Evaporation

2. Sediment

3. Saturated solution

4. Condensation

[C] Find the odd one out :

1. Baby

2. Boat

3. Sand

4. Copper

[D] Answer the following :

1. Yes

2. No

3. Decantation

4. Centrifugation

[E] Mention the method involve against the pictures :

1. Sieving

2. Handpicking

3. Condensation

4. Decantation

3. Used to separate dissolved substances from their solution.

4. Used to separate insoluble solid particles from liquid.

5. Process of settling of suspended particles.

[D] Labeling of the process : Filtration :

(a) Funnel (b) Filter paper

(c) Impurities (d) Filtrate.

P-16 SCIENCE – VI

Ans. 1. Pickle adds taste to our food. Hence, pickling of lemon is a desirable change.

Ans. 2. A change which repeats after a regular interval of time is known as perodic change.

Ans. 3. No, this change cannot be reversed because the toy cannot be repaired to its previous form.

Ans. 4. When we burn a cracker, it explodes. Heat, light and smoke come out after explosion. Many new products are formed. Hence, it is a chemical change.

Ans. 5. The changes which can be reversed by reversing the conditions are called reversible changes. For example :

1. Conversion of ice into water by heating.

2. Stretching of a rubber band.

Ans. 6. Periodic change : A change that occurs during a definite time interval is known as periodic change. E.g. Phases of moon, Heart-beat.

Non-periodic change : A change that does not repeat again and again after a regular interval of time is called non-periodic change. E.g. Earthquake, Flood.

Ans. 7. The iron blade of tools has a ring in which the wooden handle is fixed. The ring is slightly smaller in size than the wooden handle. To fix the handle, the ring is heated so that it becomes larger in size as iron expands on heating. Now, the handle easily fits into the ring and on cooling, it fits tightly due to contraction in the ring.

Ans. 1. Chemical change is permanent because in this change, an entirely new substance is formed with different properties.

Ans. 2. Yes, this change can be reversed by unfolding the paper aero plane.

Ans. 3. A piece of iron is heated till it becomes red hot, then this red-hot iron, which is quite soft, is beaten into desired shape.

Ans. 4. Vegetables and fruits are spoiled by bacteria and other microbes. To prevent them from spoilage, they are stored at low temperature in refrigerator where microbes are unable to survive.

Ans. 5. Examples of three quick natural changes are :

1. Collapsing of building during an earthquake.

2. Uprooting of trees during a tempest.

3. Tsunami.

Ans. 6. Cement bags are converted into a hard mass due to the chemical reaction with water. A new product is formed, which has entirely different properties. So, this chemical change cannot be reversed.



6 CHANGES AROUND US

P-17CHANGES AROUND US


1. (c) 2. (d) 3. (c) 4. (a) 5. (b)


1. Chemical

2. Expands

3. Condensation

4. Sublimation

5. No new substance

6. Heat or energy

7. Heating or cooling / or by mixing

8. Reversible.

[C] Change can be/cannot be reversed :

1. Can be reversed

2. Cannot be reversed

3. Cannot be reversed

4. Can be reversed.

Ans. 7. When a candle burns, both physical and chemical changes take place. On burning a candle, the wax melts and is solidified again on cooling, so, melting of wax is a physical change. But the burning of candle also produces light and some gases like carbon dioxide. Hence, the burning of wick of a candle is a chemical change.

Ans. 8.

Physical Change Chemical Change1. Only physical properties like colour, volume etc. change.

2. No new substance is formed.

3. Ex : Conversion of water into ice, tearing of paper.

1. The chemical composition and chemical properties of the reacting substances undergo a change.2. One or more new substances are formed.3. Burning of cooking gas, ripening of fruits.


P-18 SCIENCE – VI



1. (b) 2. (c) 3. (a) 4. (a) 5. (a)


1. False

2. True

3. True

4. False.


1. Yes

2. No

3. Five changes which can be reversed :

(a) Melting of wax

(b) Melting of ice

(c) Conversion of water into water vapor

(d) Freezing of water

(e) Melting of chocolate

4. Five changes which cannot be reversed :

(a) Growth of plants

(b) Ripening of fruit

(c) Souring of milk

(d) Cooking of food

(e) Burning of wax

5. Conversion of water into water vapor is called evaporation.

6. Conversion of solid into liquid is called melting.

P-19GETTING TO KNOW PLANTS

Ans. 1. Venation is the term used for the pattern of veins in a leaf.

Ans. 2. Leaves.

Ans. 3. 1. The stem carries water and mineral from the roots to the different parts of the plant.

2. Thestemprovidessupporttothebranches,leaves,flowersandfruits.

Ans. 4. Thebasicpartsofafloweraresepals,petals,stamensandpistil.

Ans. 5. Plantsareclassifiedintoherbs,shrubs,trees,climbersandcreepersonthebasisoftheir height, type of stem and the mode of branching.

Ans. 6. Yes, she is correct. Rose is categorized as shrub because it displays the following characteristics :

1. Are medium sized plants with least thickness and height.

2. Are generally bushy.

Ans. 7. Plants are characterized into three types, on the basis of several features. One of the features is type of stem.

Trees : They are tall, have hard, thick and woody stem.

Shrubs : They are medium height, have hard and woody stems.

Herbs : They are short and have tender, green and short stems.

Ans. 8. A leaf is a thin expanded outgrowth arising form the node of a stem. The part by which it is attached to the stem is called a petiole. The broad green part of the leaf is called lamina. The lines on the leaf are called veins. The thick vein in the middle of the leaf is called mid rib. The design made by the veins on the leaf is called venation. If the design is net like, it is termed as reticulate venation whereas if the veins are parallel to each other, it is termed as parallel venation.


7 GETTING TO KNOW PLANTS

P-20 SCIENCE – VI


Ans. 1. Leaf.

Ans. 2. Oxygen.Ans. 3. Fibrous root.Ans. 4. Three types of plants are : 1. Herbs, 2. Shrubs, 3. Trees.Ans. 5. There are two parts of leaf : Petiole is the part of the leaf or small stalk by which the leaf is attached to the stem.

Laminaistheflat,thinandbroadpartwithconspicoussystemofveinsandveinlets.Ans. 6. Creepers : 1. Stem is thin, delicate, weak and unable to stand erect. 2. May grow prostrate on ground or may get buried in the top soil. 3. Examples : Pumpkin, grass etc. Climbers : 1.Stemislong,flexibleandgoupandwinedaroundthesupport. 2. Take support of the nearby objects to climb. 3. Examples : Pea.Ans. 7. Roots perform following functions : (a) Roots absorb water and minerals from the soil. (b) Roots hold the plant to the soil. (c) Roots store food.Ans. 8. Characteristics of plants are : (a) They cannot move from one place to another. (b) They can prepare their own food. (c) These are the living organisms one the earth which are responsible for the

formation of food for all the living forms directly or indirectly. (d) All other organisms one the earth depend on the plants and their products for

thier survival.

(e) These living things grow in the soil from where they take nutrients for their growth and propagation.

[A] Multiple Choice Type Questions : 1. (b) 2. (c) 3. (b) 4. (a) 5. (d)[B] Fill in the blanks : 1. Root 2. Gynoecium 3. Stem 4.Antherandfilament 5. Corolla (petals).[C] MaindifferencebetweenTaprootandfibrousroot: Tap root : There is one main root, then the branches of roots arise. They are found

in dicotyledons.


P-21GETTING TO KNOW PLANTS



1. (a) 2. (a) 3. (a) 4. (a) 5. (b)

[B] Answer the following :

1. Roots help in absorption of water from soil.

2. The stem carries water and minerals from the roots to the different parts of the plants.

3. Leaves prepare food through the process of photosynthesis.

[C] Students should draw themselves.

[D] 1. Stamens, pistil.

2. Anther,filament

3. Style, stigma, ovary.

Fibrous root : There is no main root. All the roots form branches. They are found in monocotyledons.

[D] Give two examples : Herbs : Coriander, Mint Shrubs : Tulsi, Rose Trees : Mango, Apple.[E] Name the following : 1. Antherandfilament 2. Stigma, style and ovary 3. Petals.

P-22 SCIENCE – VI

Answer the following :

Ans. 1. The joint where our neck joins the head is a pivotal joint.

Ans. 2. Thebonescannotmoveatfixedjoints.

Ans. 3. Fish has a spindle shaped streamlined body. This shape of the body helps it to move inwater.Fishuseitsmusculartailandfinsforswimming.

Ans. 4. Thebackboneextendsfromthenecktothehip.Itconsistsofmanysmallbonescalledvertebrate joined to end. The ribs are joined to these bones.

Ans. 5. Cartilageisthepartoftheskeletonthatisnotashardasthebones.Itcanbebenteasily.Wecanfindthecartilageintheupperpartofear.

Ans. 6. Body of the snail is covered with a hard shell. This shell does not help the snail in movement.Headofthesnailmaycomeoutofanopeningintheshell.Thesnailhasathickandstringmuscularfoot.Footmovesslowlywithawavymotion.

Ans. 7. Setae are bristle like projections on the lower side of the bodies of earthworms and leeches,asearthwormdoesnothavebones,muscleshelpittoextendandcontractthebody to help in its movement. The bristles are connected with muscles. The bristles helptogetagoodgripontheground.

Ans. 8. Theframeworkofbonesandcartilagewhichsupportsthebodyofananimaliscalleditsskeletonsystem.Humanskeletonsystemismadeupof206bonesandcartilage.The human skeleton system consists of the skull, backbone, ribs, breastbones, bones inarmsandlegs,shoulderandhipbones.

Functions of the skeleton system :

1.Itformsframeworkofthebody.

2.Ithelpstoprotectthedelicateorgansofthebodyintheirproperpositions.


8 BODY MOVEMENTS

SUMMATIVE ASSESSMENT WORKSHEET-30Ans. 1. Pelvic bones enclose the portion of our body below the stomach.

Ans. 2. Gait of animals refers to the way of movement in animals.

Ans. 3. Thebirdsareverylightinweightbecauseofthepresenceofhollowbones.Thisisanadaptationwhichalongwithfeathersandwings,helpthebirdstofly.

Ans. 4. Inballandsocketjoint,theroundendofonebonefitsintothecavityoftheotherbone,e.g.,thighandhipjoint.Thistypeofjointallowsmovementsinalldirections.

Ans. 5. Fixed joint istheonewherethereisnorelativemovementofthebones.Thejointbetweentheheadandtheupperjawisanexampleoffixedjoint.

Ans. 6. Duringmovement,theearthwormfirstextendsthefrontpartofthebody,keepingtherearportionfixedtotheground.Thenitfixesthefrontendandreleasestherearend. Then shortens the body and pulls the rear end forward. This makes it move

P-23BODY MOVEMENT

forwardbyasmalldistance.Repeatingsuchmuscleexpansionsandcontractions,theearthwormcanmovethroughsoil.

Ans. 7. Thevertebralcolumnpresentinhumanbodyiscommonlycalledbackbone.It isalongtubularstructurestartingfromncekregionandrunsinthebackportionofthehumanbody.Itconsistsofmanysmallbonescalledvertebrae.Thesevertebraearejointedendtoend.Thevertebralcolumnprotectsthespinalcordandgivessupporttothe whole body.

Ans. 8. Anorganismwillnothaveanybodyshapeifitdonothaveaskeleton.Theskeletoninadditionofprovidingbodyframeworkperformsseveralimportantroles.Theyarenamely :

1. Protectionofinternalorgans.

2. Storehouse of minerals.

3. Production of blood cells.

Ans. 9. Cockroacheswalkandclimbaswellasflyintheair.Theyhavethreepairsoflegswhichhelptheminwalking.Thebodyiscoveredwithahardouterskeleton.Thisouterskeletonismadeupofdifferentunitsjoinedtogetherwhichpermitmovement.Therearetwopairsofwingsattachedtothethorax.Thecockroacheshavedistinctmuscles,thosenearthelegsmovethelegsforwalking.Thethoracicmusclesmovethewingswhenthecockroachflies.



1. (c) 2. (c) 3. (d) 4. (c) 5. (d)


1.Ribs 2.Skeleton 3.Hingejoint

4.Immovable 5.Abdomen 6.Cartilage

7.Muscles 8.Streamlined 9.Lightandhollow

10. Muscular foot 11. Movement 12. Muscles

13.Contractionandrelaxation 14.Gaitofanimals.

[C] Difference between bone and cartilage :

Bone Cartilage1. Bones cannot be bent.

2. They are hard.

3.Example:Backbone

1.Cartilagecanbebent.

2. Cartilage is not as much hard as bones.

3.Examples:Upperpartoftheear.

P-24 SCIENCE – VI



1. (a) 2. (b) 3. (a) 4. (b) 5. (c)


1. Skeletal system

2. No

3. Skull joint

4. At shoulders/hip joint

5. Elbow/knee.

[C] Match the following :

1. Heart

2. Muscular foot

3. Brain

4. Fins

5. Ear

[D] Identify the following :

1. Ribcage

2. Skull

3. Pelvic bones

4. Shoulder bones.

P-25THE LIVING ORGANISMS AND THEIR SURROUNDINGS


9 THE LIVING ORGANISMS AND THEIR SURROUNDINGS

Ans. 1. Presenceofgillsforrespirationhelpsafishtolivecomfortablyinwater.

Ans. 2. Terrestrialhabitat.

Ans. 3. Thepresenceofspecificfeaturesorcertainhabits,whichenablesaplantoranimaltoliveinitshabitatcomfortably,iscalledadaptation.

Ans. 4. Biotic components include living things such as plants and animals. Abioticcomponentsincludenon-livingthingssuchasair,water,soil,rock,heatandlightetc.

Ans. 5. Adaptationdoesnottakeplaceinashorttime.Theabioticfactorsofaregionchangeoverthousandsofyears.

Ans. 6. (a) Ithaslongearstohearthemovementsofitspredators.

(b) Theeyesonthesideofitsheadhelpittolookinalldirections.

(c) Ithashighspeedofrunningwhichhelpsittorunawayfromitspredators.

Ans. 7. (a) Animalsandplantsareadaptedtotheconditionsofthehabitatsinwhichtheylive.Animalscanliveinmanydifferentplacesintheworldbecausetheyhavespecialadaptationstotheareathey live in.Animalsdependontheirphysical featurestohelpthemobtainfood,keepsafe,buildhomes,withstandweatherandattractmales.Thesephysicalfeaturesarecalledphysicaladaptations.Theymakeitpossiblefortheanimaltoliveinaparticularplaceandinparticularway.

(b) Exchangeofgasesinanearthwormtakesplacethroughitsmoistskin.

Ans. 8. Thecharacteristicsoflivingthingsareasfollows:

1. Alllivingthingsneedfood.

2. Theyallrespire.

3. Theyexhibitgrowth.

4. Alllivingthingscanreproducetheirownkinds.

5. Theyshowresponsetostimuli.

6. Theyexhibitmovement.

7. Alllivingthingsexcrete.

P-26 SCIENCE – VI


Ans. 1. Aquatichabitat.Ans. 2. Therearetwocomponentsnamedasbioticandabioticcomponents.Ans. 3. Dolphinsbreatheinairthroughnostrilsorblowholesthatarelocatedontheupper

partofitshead.Ans. 4. Yakshavelonghairandleopardhasthickfuronitsbodyincludingfeetandtoesto

preventthemfromextremecold.Ans. 5. Ratsandsnakesescapetheintenseheatofthedesertbyhidingthemselvesdeepinto

theburrowsinthesandduringday.Theycomeoutduringthenightwhenitiscooloutside.

Ans. 6. Acamelhasfollowingadaptationstosurviveinadesertenvironment: 1. Ithaslonglegstoescapefromtheheatofthesand. 2. Itcanlivewithoutwaterforseveraldays. 3. Itexcretesdrydungandsmallamountofurine.Ans. 7. (a) Animalslivinginthegrasslandshavetorunawaywithagreatspeedtoescape

fromtheirpredators.Hence,speedisimportantfortheirsurvival.

(b) LotusandwaterHyacinth.Ans. 8. Cactusismostlyfoundinthedeserts.Ithasthefollowingspecialfeaturestoadapt

itselftosurviveinthedesert: 1. Leavesaremodifiedintothespinestoreducetherateoflossofwater. 2. Stembecomesgreenandfleshytotakeoverthefunctionofphotosynthesis. 3. Stemisalsocoveredwithathicklayerofwaxtoretainwater. 4. Itsrootsgodeeperintothesoilforbetterabsorptionofwater.

SUMMATIVE ASSESSMENT WORKSHEET-35[A] Multiple Choice Type Questions : 1.(a)2.(d)3.(d)4.(c)5.(b)

[B] Fill in the blanks : 1. Habitat

2. Aquatic

3. Abiotic

4. Cactus

5. Salinewater

6. Acclimatization.

[C] Name the following : 1. Blowholes

2. Prey

3. Adaptations

4. Excretion

5. Acclimatization.

P-27THE LIVING ORGANISMS AND THEIR SURROUNDINGS



1.(a)2.(b)3.(b)4.(a)5.(a)


1. Livingthingscanmove.

Livingthingscanreproduce.

Livingthingscangrow.

2. Gills

3. Plantsandanimals

4. Air,water,soilandsunetc.

[C] Give two examples each of the following :

1. Marineanimals:Shark,Whale

2. DesertAnimals:Camel,rat

3. DesertPlants:Cactus,Acacia

4. Mountainanimals;Yak,Llama

5. Floatingplants:Lotus,Hydrilla

6. Grasslandanimals:Lion,Deer.

P-28 SCIENCE – VI

Ans. 1. The change in the position of an object with time is called motion.

Ans. 2. 1 cm = 10 mm.

Ans. 3. The two devices that are used to measure length are :

1. Meter scale, 2. Screw gauge.

Ans. 4. 1m = 100 cm = 1000 mm

The height of the given person in cm will be 1965 cm.

The height of given person in mm will be 19650 mm.

Ans. 5. The two examples of a periodic motion are :

Motion of a pendulum and motion of a child on a swing.

Ans. 6. Linear motion : A moving car in a straight line.

Circular motion : Motion of blades of fan.

Rotatory motion : Rotation of blades of fan.

Ans. 7. 1. Length of a scale that you are using to measure, must be greater than the length of the object.

2. The eye must be placed just above the point that you are reading, otherwise there will be an error due to parallax.

3. If the zero mark of the scale is damaged or the edge of the scale is not smooth, then start the measurement form another mark.

Ans. 8. Draw a curved line CD. Take a thread and make a knot at one of its end. Keep the knot made in the thread on point C of the line. Place a small portion of the thread along the line, keeping it taut using fingers and thumb. Keep on stretching the thread on the curved line till you take the thread to the point D of the line. Make a mark on the thread where it touches the other end of the line at point D. Now, stretch the thread along a meter scale and the length between the knot in the beginning and mark on the thread is measured through scale. This measure length on scale will give you the length of the curved line CD.


10 MOTION AND MEASUREMENT OF DISTANCE

P-29MOTION AND MEASUREMENT OF DISTANCE


Ans. 1. Time taken by the earth to revolve around the sun is called a year.

Ans. 2. The comparison of an unknown quantity with a standard quantity is known as measurement.

Ans. 3. A quantity adopted as a standard of measurements of a physical is called a unit.

Ans. 4. The mode of transport which are used on land are : bus and car.

Ans. 5. Foot, hand span and arm length are used to measure the length. These are inexact methods of measurement.

Ans. 6. Similarities between the motion of a bicycle and a ceiling fan :

1. The blades of a fan and the wheels of a bicycle are fixed at a point.

2. Both have circular motion about their respective fixed points.

Differences between the motion of a bicycle and a ceilling fan :

1. A bicycle has linear motion, whereas the blades of a ceiling fan do not have linear motion.

2. The motion of the blades of a fan is periodic whereas the motion of a bicycle is rectilinear motion.

Ans. 7. The size of the foot varies from person to person. If footsteps of two persons are used to measure the length respectively, then the two distances may not be equal. Thus, a footstep is not a constant quantity. Hence, it cannot be used as a standard unit of measurement.

Ans. 8. 1. First, we must choose a suitable device for measuring the length of an object, like a measuring tape is used to measure the growth of a tree while a measuring scale is used to measure the length of a book.

2. When we measure the length of an object with a scale, we should place the scale in contact with an object along its length and align the zero mark of the scale with the starting point of the object.

3. While taking the reading, eye must be placed vertically above the point where the measurement has to be taken, otherwise there will be an error in the reading which is taken due to parallax.

4. If the scale is damaged from the edge or it is not smooth and if the zero mark on the scale is damaged, then start the measurement from another point.

P-30 SCIENCE – VI




1. (c) 2. (c) 3. (d) 4. (b) 5. (c)


1. 100 cm 2. 5000 m

3. Oscillatory motion 4. Circular

5. Periodic motion

[C] 6.38 m = 6.38 × 100 = 638 cm

6.38 m = 6.38 × 1000 = 6380 mm

6.38 m = 6.38/1000 = 0.00638 km

[D] SI unit of length = Meter, time = Second

[E] Identify the types of motion from the picture :

1. Rotatory motion

2. Circular motion

3. Rectilinear motion.


1. (b) 2. (c) 3. (c) 4. (c) 5. (c)


1. Types of motion : rectilinear motion, circular motion, periodic motion.

2. Examples of rectilinear motion : car moving on a road, soldiers in march past.

3. Examples of periodic motion : rotation of earth, beating of hear.

4. Examples of circular motion : car moving in a circle, movement of fan blades.

[C] Ancient units are : Cubit, Foot, Hand span.

[D] Match the following :

1. 10 mm : 1 cm

2. 1 km : 1000 m

3. Time : sec

4. 10 m : 1000 cm

5. 1 cm : 100 m

P-31LIGHT SHADOWS AND REFLECTIONS

Ans. 1. Materials through which light can pass partially are called translucent materials. For example : Wax paper.

Ans. 2. Light is a source of energy. It cannot be seen but it enables us to see things.

Ans. 3. The two effects of light on plants are :

(a) Plants use light for the preparation of their food through the process of photosynthesis.

(b) Someplants(likesunflower)moveinthedirectionoflight.

Ans. 4. No, we will not be able to see our image in the mirror if there is no source of light. We

canseeourimageinthemirroronlywhenthelightisreflectedfromthemirror.

Ans. 5. When a beam of light is incident on a smooth surface, a part of it bounces back into thesamemedium.Thisisknownasreflectionoflight.

Ans. 6.

Transparent objects Translucent objects1. They allow light to pass completely through them.

2. Objects through them can be seen clearly.

3. E.g. Glass, Air

1. They allow the light to pass partially through them.

2. Objects through them can’t be seen clearly.

3. E.g. Butter paper, Wax paper.

Ans. 7. Thelightalwaystravelsinastraightline. This can beshownbyperformingasimpleactivity.Forthis,firstofallletustake

three cardboards of equal size. Now, a hole is made at the center of each cardboard at thesamelevel.Thethreecardboardsareplacedonaflattableandalignedlinearly.

Acandleislightedatoneendofthetablewithitsflameattheleveloftheholesandisseenattheotherend.Itisobservedthatthelightofthecandleisseeneffortlessly.Now, the middle of the three cardboards is displaced from its position. Now, we are unabletoseethelight.Thereasonbehindthisis,thatthelighttravelsinastraightline.

Ans. 8. Opaque objects does not allow light of pass through them. When an opaque object is placed in the path of light, then the light is obstructed by an object leading to the formation of a dark patch known as shadow of that object, which can be taken on a screen placed behind it.

Shadow formation : To form a shadow, there must be a light source, a screen, an opaque object placed between the light source and the screen. For shadow formation, we can follow the following steps :

1. Take an opaque object. 2. Throw light on it from a light source.

3. Put a screen behind the object.

In this way, a shadow of an object can be obtained on the screen.


11 LIGHT, SHADOWS AND REFLECTIONS

P-32 SCIENCE – VI

Ans. 1. Materials that allow light to pass through them, are called transparent materials. For example : Glass.

Ans. 2. Materials that does not allow light to pass through it is called an opaque material. For example : Wood.

Ans. 3. Thelightfromthefacestrikesatthesurfaceofthemirrorandisreflectedfromthesurface of it and reaches our eye. Hence we are able to see our face in the mirror.

Ans. 4. Thetransparentglasssheetcanbeconvertedintoatranslucentglasssheetbythefollowing ways :

(a) Bycoveringonesideoftheglasswithbutterpaper. (b) Bycoveringonesidewithathinsheetofplastic.Ans. 5. Some important properties of light are as follows : (a) Lighttravelsinastraightline,whichiscalledrectilinearpropagationoflight. (b) Lightexhibitsthepropertyofreflection.Ans. 6. Take two boxes such that one can slide into the other with no gap in between them.

Cut the same side of each box. Make a small hole in the middle of the opposite side of the larger box and cut out a square from the middle of the opposite side of the smaller box.Thisopensquareshouldbecoveredwithatracingpaper.Slidethesmallerboxinside the larger one in such a way that its side with the tracing paper is inside.

Ans. 7. Natual sources of light are : Stars,Firefly,Sun Artificialsourcesoflightare: Electric bulb, Candle, Gas lamp.Ans. 8. Solar Eclipse : When the Sun, the Earth and the Moon comes in a straight line with

the moon in between the earth and the Sun, then the shadow of the moon falls on the Earth. This results in solar eclipse. Solar eclips takes place on a new moon day.

Lunar Eclipse : When the Sun, the Earth and the Moon comes in a straight line with the earth in between the moon and the Sun, then the shadow of the earth falls on the moon. This results in lunar eclipse. Lunar eclipse takes place on a full moon day.


P-33LIGHT SHADOWS AND REFLECTIONS




1. (c) 2. (a) 3. (b) 4. (d) 5. (a)


1. Light 2. Luminous objects

3. Transparent 4. Opaque

5. Translucent 6. Straight line

7. Shadows 8. Source of light and opaque

9.Eclips 10.Realandinverted

11.Image 12.Naturalandartificial

13.Sun 14.Reflectinglightthrough

15. Point.

[C] Studentshoulddrawthemselves.


1. (a) 2. (b) 3. (a) 4. (a) 5. (b)

[B] Give one word :

1. Luminous

2. Opaque

3. Transparent

4. Shadow

5. Solar eclipse

[C] Give two examples :

Transparent : Glass, Water

Translucent : Butter paper, greased paper

Opaque : Book, a piece of wood.

[D] 1. Light is necessary for the process of photosynthesis.

2.Lightgivesalllivingbeingsthesensationofsight.

3.Lightisessentialforthegrowthoflivingbeings.

P-34 SCIENCE – VI

Ans. 1. It is a source of electricity.

Ans. 2. Materialsthroughwhichanelectriccurrentcanflowwecalledconductors.

Ans. 3. Theelectriccellproduceselectricityduetochemicalreactionsthatoccursinsideit.

Ans. 4. Materialsthroughwhichanelectriccurrentcannotflowarecalledasinsulators.Forexample:Rubber.

Ans. 5. Thedeviceswhichmakeuseoftheelectriccellsare:

1.Transistorradios 2.Cameras 3.Wristwatches

4.Alarmclocks.

Ans. 6. Thetwoinsulatorsare:PlasticandRubber

Thetwoconductorsare:AluminumandCopper

Ans. 7. Whentwo,ormorethantwoelectriccellsareconnectedtogether,insuchawaythatthepositiveterminalofonecellisconnectedtothenegativeterminaloftheother,thenwecallitasabattery.

Ans. 8. Anelectriccell consistsof cylindricalpotwhich iscoveredbya thickpapersheet.Itconsistsoftwoterminals.Oneiscalledpositiveterminalandtheotheriscallednegativeterminal.Themetalcapisthepositiveterminalandthemetaldiscisthenegativeterminaloftheelectriccell.Theproductionofelectriccurrenttakesplaceduetothechemicalreactionsinsidethecell.Thechemicalsarepresentbetweentheoutermostcoveringofthecellandcarbonrod.


12 ELECTRICITY AND CIRCUITS

P-35ELECTRICITY AND CIRCUITS

Ans. 1. Wegetanelectricshockbecauseourbodyisaconductorofelectricity.

Ans. 2. ThetwodevicesthatworkonelectricityareFanandElectricbulb.Ans. 3. Whenthefilamentofabulbisbroken,itiscalledafusedbulb.

Ans. 4. Anelectricianshoulduserubbergloveswhencarringoutelectricalrepairs,becauseourbodyisagoodconductorofelectricityandelectricitycanflowinthebodywithoutrubbergloves.Whenheusesrubbergloves,electricitydoesnotflowinbody,becauserubberglovesareinsulators.Therefore,anelectricianshoulduserubbergloveswhilerepairing electricial appliances.

Ans. 5. Whenmainsswitchisturnedoff,allthelightsandfansgooffinourhousebecausethecurrentflowsintheappliancesthroughthemainswitch.Whenitisturnedoff,flowofcurrentstopsandthelightsandfansgooff.

Ans. 6. Thecellsused incalculatorsareknownasbuttoncellsas theyresemblewith theshapeofabutton.Theplatesofthesecellsaremadefromcompoundsofnickelandcadmium.Themainadvantageofthesecellsisthattheycanstayinanactivestageformonths.

Ans. 7. Thechemicalenergystoredinthechemicalsinsideacellwillconvertintoelectricalenergy.Whenthechemicalsofthecellsareusedup,itstopsproducingelectricity.

Ans. 8. Weshouldsaveelectricitybecauseitisformedformmanynon-renewableresources.

Threewaystominimizeelectricityare:

1. Switch off the electrical appliance when not in use.

2.Useoftheapplianceswithlesserpowerconsumption.

3.Minimizetheextrauseoftheappliances.



1.(b)2.(d)3.(b)4.(a)5.(b)

[B] Name the following :

1. Switch 2. Two 3.Electricalenergy

4.Power 5.Circuit 6.Fused

7. Insulator 8.Cell 9.Conductors.

[C] Studentshoulddrawthemselves.

[D] Mark true or false :

1.True 2.False 3.False 4.True 5.False.


P-36 SCIENCE – VI



1.(c)2.(c)3.(b)4.(a)5.(c)

[B]

Conductor Insulator

1.Substancethatallowselectricity to pass through it.

2.E.g.Copper.

1. Substance that does not allow electricity to pass through it.

2.E.g.Plastic.

[C] Studentshoulddrawitthemselves.

[D]

Conductor Insulator

Key,Nickel,Penny Rubber band, Tooth pick, Paperclip,Glassmicroscopicslide.

P-37FUN WITH MAGNETS

Ans. 1. Both the magnets will repel each other in this case.

Ans. 2. A material which shows an attraction for magnetic materials such as iron, cobalt and nickel is called magnet.

Ans. 3. The two magnetic materials are : Iron, Cobalt.

The two non-magnetic materials are : Leather, Plastic.

Ans. 4. Temporary magnet is the magnet which loses its magnetism as soon as the source of magnetism is removed. It is usually made up of soft iorn.

Ans. 5. The two properties of a magnet are given as follows :

(a) Magnet has two poles which cannot be separated from each other.

(b) Magnet attracts magnetic materials like Iron, Cobalt and Nickel towards itself.

Ans. 6. Attractive Property : A magnet has the property to attract some substances like Iron, Cobalt, Nickel when brought near it. This property of magnet is called as an attractive property.

Directive Property : If we suspend a magnet freely with a thread, then it always aligns itself with the geographic north-south direction when it comes to rest. This is called as directive property of a magnet.

Ans. 7. Earth behaves like a huge bar magnet with poles at its end. The north pole of this bar magnet points approximately towards the geographical south-pole and its south-pole points towards geographical north-pole. This is because it is attracted by the Earth’s magnetic south-pole and vice-versa. Hence, the freely suspended magnet always aligns itself in the north-south direction.

Ans. 8. The poles of bar magnet are located at its two end points. Place a magnet on paper and sprinkle some iron fillings on it. It is observed that the iron fillings get attracted more strongly towards the two ends of the magnet compared to its central position indicating that the poles are located at these two ends of the magnet.


13 FUN WITH MAGNETS

Ans. 1. In an electric bell, U-shaped magnet is used.

Ans. 2. Natural magnet is naturally occurring ore of iron.

Ans. 3. A freely suspended magnet always aligns itself in the geographical north-south direction.

Ans. 4. A magnetic keeper is a piece of iron. In Keepers two magnets are arranged with their opposite poles lying side by side. A piece of wood should be kept between them and two pieces of soft iron placed across the poles.

Ans. 5. A magnet can be demagnetized : 1. By heating. 2. By hammering the magnet violently.

Ans. 6. Magnets have various uses. They are used in magnetic compass, Electric motors, Refrigerators doors, Electric bells, T.V., Radio, Computers etc.


P-38 SCIENCE – VI



1. (c) 2. (b) 3. (d) 4. (a) 5. (a)


1. Magnetic material 2. Repel 3. Magnetic compass

4. Attract 5. Magnetic 6. Two

7. Poles 8. Greece

[C] Uses of electromagnet :

1. It is used in loudspeakers.

2. It is used in electric bell.

[D] Take a rectangular piece of iron. Place it on the table. Now take a bar magnet and place one of its poles near one edge of the bar of the iron. Without lifting the bar magnet, move it along the length of the iron bar till you reach the other end. Now lift the magnet and bring the pole to the same point of the iron bar from which you began. Move the magnet again and repeat this process 30-40 times.

[E] Which pair will attract or repel :

1. Repel

2. Attract.

Ans. 7.

Ans. 8. When the magnet is suspended freely with the thread, it aligns itself in the geographical north-south direction. We use this property of magnet in compass, which is used to give us the direction at a particular place. The diagram of the compass is shown in the figure below :

P-39FUN WITH MAGNETS



1. (c) 2. (b) 3. (a) 4. (b) 5. (a)

[B] Answer the following questions :

1. Greece

2. Iron

3. Poles

4. Lodestone.

[C] Give one word :

1. Permanent magnet

2. Magnetite (Loadstone)

3. Poles

4. Magnetic material

5. Steel

6. Magnetic keepers.

[D] True or false :

1. False

2. False

3. True

4. True.

P-40 SCIENCE – VI

Ans. 1. Water cycle plays an important role in the global climate :

(a) Water cycle maintains the temperature on land.

(b) Water cycle regulates the ground water level.

Ans. 2. Seawater contains largeamountof salt indissolved state.Hence, it isnotfit fordrinking.

Ans. 3. When rainfall does not happen for more than a year in a region, then that region faces adeficiencyofwater,whichisknownasdrought.

Ans. 4. Oxygen is slightly soluble in water. Fish and aquatic plants need oxygen to survive and they inhale this dissolved oxygen for their survival.

Ans. 5. Lakes and ponds are formed by the collection of rain water in low lying areas and leakage from the ground water reserves also adds water to it.

Ans. 6. Wet clothes dry up quickly in sunlight due to the evaporation of water. Rise in temperature of the surrounding increases the rate of evaporation and the temperature in sunlight is generally greater than that in shade.

Ans. 7. We can conserve water by following means :

(a) Do not waste water and repair all the water leaking taps.

(b) Do not use drinking water in garden.

(c) Do not throw any waste in ponds or rivers to prevent water pollution.

Ans. 8. The water vapors that go into the air, rise up along with air. As the air moves up, watervaporsgetcooler.Atsufficientheight,airbecomessocoolthatthewatervaporspresent in it condenses into tiny droplets of water. When these water droplets come closer they combine to form slightly bigger droplets. In this way, their size becomes larger. Once the size of these droplets becomes large, then they collectively appear to us as clouds.

Ans. 9. Uses of water are :

(a) For drinking and cooking

(b) For bathing and cleaning

(c) In agriculture

(d) In industries to perform different activities.

(e) For generating electricity.


14 WATER

P-41WATER


Ans. 1. Fog is a form of condensed water vapours on dust particles in air and it occurs near the surface of the earth during winter season.

Ans. 2. Plants lose their excess water through their pores of leaves in the vapour form. This process is called transpiration.

Ans. 3. The two sources of natural water are river water and lake water.

Ans. 4. Water is called as universal solvent because it dissolves most of the salts and substances in it.

Ans. 5. Engines releases large amount of heat. This heat gets consumed in the conversion of water into water vapours. Therefore engine parts are not heated up.

Ans. 6. Water from the oceans and surface of the earth goes into the air as vapours and returns as rain, hail or snowandfinally goes back to the oceans.The circulationof water in this manner is known as water cycle. This circulation of water between ocean and land is a continuous process. It maintains the supply of water on land.

Ans. 7. Three measures to prevent water pollution :

(a) By not throwing waste materials and garbage into water.

(b) By sensitizing people about harmful effects of water pollution.

(c) By making separate sewage system for disposal for human excreta.

Ans. 8. Rain water harvesting is a technique in which rain water is collected from the rooftop to a storage tank. Then this water is allowed to seep into a pit in the ground. Finally itseepsintothesoiltorechargeorrefillgroundwater.


[A] Multiple Choice Type Questions : 1. (b) 2. (c) 3. (c) 4. (c) 5. (a)[B] Rain water harvesting : 1. It helps to store water for future use. 2. Stored water can be used for irrigation purpose.[C] Students should draw the diagram themselves.

P-42 SCIENCE – VI



1. (b) 2. (a) 3. (d) 4. (d) 5. (a)

[B] Various sources of water on the earth are rain, ground water, hail, snow and sleet.

[C] Coin one word for the following :

1. Rainwater harvesting

2. Evaporation

3. Drought

4. Flood

5. 70

6. Water cycle

7. Transpiration

8. Potable water

9. Tap

10. Ground water.

P-43AIR AROUND US

Ans. 1. When the air is in motion, then it is called wind.Ans. 2. Oxygen gas in the atmosphere is essential for respiration.Ans. 3. Aquatic animals use the dissolved oxygen in water for respiration.Ans. 4. The air consists of following: Nitrogen 78%, Oxygen 21%, Carbon dioxide, water

vapours, dust and other gases.Ans. 5. The air is considered a mixture because of the following reasons : (a) Air consists of many gases like nitrogen, oxygen, carbon dioxide etc. (b) The composition of air varies from place to place.Ans. 6. This can be proved by an experiment. Take an empty bottle and dip it into the bucket

filled with water. You will notice that water does not enter in the bottle due to the presence of air inside the bottle. As soon as you tilt the bottle, air gets way to escape from the bottle and water fills up the space.

Ans. 7. On a sunny day, go to a room which is a little bit dark. In this room choose a thin opening through which light can enter the room. If there is no opening in the room then make one. From this opening we will see that a strip beam of sunlight enters the room. In this beam we will observe that there are some tiny solid like particles moving freely. These particles are the dust particles and this shows the presence of dust particles in the air.


15 AIR AROUND US

SUMMATIVE ASSESSMENT WORKSHEET-58Ans. 1. The layer of air around the earth is known as atmosphere.

Ans. 2. Carbon dioxide gas is used by green plants to make their food.

Ans. 3. The most abundant gas in our atmosphere is nitrogen.

Ans. 4. Four activities that are possible due to the presence of air are as follows :

(a) Respiration and water cycle

(b) Flying of birds and aeroplanes

(c) Dispersal of seeds

(d) Rotation of the windmill

Ans. 5. As we move up in the atmosphere, the air becomes thin because of this, mountaineers feel little difficulty in inhaling oxygen. To overcome this problem, they carry oxygen cylinders along with them.

Ans. 6. Both plants and animals are interdependent on each other for their survival. Plants cannot survive for long time without animals because they need carbon dioxide for photosynthesis, which is exhaled by animals. Similarly, in absence of plants there will be no oxygen for animals to breathe in. Hence we can say that both need each other and the balance of oxygen and carbon dioxide in the atmosphere is maintained by their presence.

Ans. 7. A wind mill is a machine that harness wind energy to grind grain, pump water or generate electricity. The wind mill is used to draw water from tube wells and to run flour mills they are also used to generate electricity.

P-44 SCIENCE – VI



[A] Multiple Choice Type Questions : 1. (c) 2. (a) 3. (d) 4. (b) 5. (b)[B] Fill in the blanks : 1. Atmosphere 2. Carbon dioxide 3. 21

4. Nitrogen 5. Oxygen[C] Match the following : 1. Major part of the air 2. Needed for respiration and burning 3. Mixture of gases 4. A thin layer of air 5. Used by plants for making food 6. By burning fuels[D] Uses of wind mill : 1. To draw water through hand pump. 2. To produce electricity. 3. To run a flour mill.


1. (b) 2. (c) 3. (a) 4. (b) 5. (c)


1. Condensation.

2. The layer of air around the earth is known as atmosphere.

3. Photosynthesis and Respiration.

[C] Students should draw the diagram themselves.

Ans. 8. The uses of air are given as follows :

(a) It is used to inflate the tyres of vehicles.

(b) It is used by plants and animals for respiration.

(c) It is used to run windmill that also produces electricity.

(d) It is used in many chemical reactions.

(e) It is needed for the dispersal of seeds.

P-45GARBAGE IN, GARBAGE OUT

Ans. 1. Red worms have gizzard for grinding the food.

Ans. 2. Garbage is an unwanted or undesired material or substance.

Ans. 3. Leftover food at home should be dumped into the compost pit.

Ans. 4. The usage of plastic bags must be reduced as packaging of cooked food items in plastic bags might affect our health. Also, plastic bags are non-biodegradable and burning of plastic bags may release harmful gases that can cause many health diseases.

Ans. 5. The method of preparing compost with the help of red worms is called vermi composting.

Ans. 6. The garbage which contains pieces of cloth, broken glass, aluminium wrappers, polythene bags, nails, broken toys, and old shoes cannot be converted into compost by red worms.

Ans. 7. Plastic bags, cans, aluminium foils and many other packaging materials are thrown after use as garbage. Things like ghee, oils, soaps, cereals, snacks, even vegetables are available in smaller packets in which a lot of packaging material is used.

Ans. 8. Converting plant and animal waste into manure is called composting. Yes, it is better to use compost instead of chemical fertilizer due to the following reasons:

(a) Compost provides better and natural nutrients to the growing plants.

(b) It is better absorbed by the roots.

(c) It is cheaper than the chemical fertilizers.

(d) Chemical fertilizers do not get decomposed easily by natural methods thus increase soil and water pollution.


16 GARBAGE IN, GARBAGE OUT


Ans. 1. No, some of the garbage that can be recycled or converted into compost is useful.

Ans. 2. It is a paste made up of paper, clay and rice husk.

Ans. 3. Alandfillisasiteforthedisposalofwastematerialsbyburialandistheoldestformof waste treatment.

Ans. 4. (a) Theproblemsrelatedtodisposalofthegarbagecanbemanagedbylandfillings. Alandfillisalowlyingopenareawheregarbagecanbedumped.

(b) Compost is a mixture that consists of decayed organic matter and is used for fertilizing and conditioning land.

Ans. 5. They eat food items like fruits and vegetables wastes, tea and coffee remains and weeds from the garden.

Ans. 6. Wasterecyclinghassomesignificantadvantages.

(a) It Leads to less utilization of raw materials.

(b) Reduces environmental impacts arising from waste treatment and disposal.

P-46 SCIENCE – VI

(c) Savesonlandfillspace.

(d) Saves money.

(e) Reduces the amount of energy required to manufacture new methods.

(f) Makes the surroundings cleaner and healthier.

Ans. 7. Waste management is the collection, transport, processing, recycling and reuse of the usable waste material. Proper disposal of garbage should be of concern to every citizen and not just of the government. Each and every individual must reduce activities that pollute the environment.A lot ofwaste is generated fromhomes, offices, schools,hospitals etc. It includes food waste, paper, plastic, glass, metal etc. Therefore it is required that every individual must reduce the production of wastes and must help in the proper disposal of these wastes.

Ans. 8. The drawbacks of plastics are :

(a) The major drawback of plastic is its non-degradability.

(b) Consuming food packed in plastic bags could be harmful to our health.

(c) All kind of plastics give out harmful gases on burning.

(d) Someanimalslikecowsswallowplasticbagsfilledwithgarbageandtheycan die due to this.

(e) The plastic also block the sewage system and the drains as a result of which the water spills over the roads.


[A] Multiple Choice Type Questions : 1. (b) 2. (a) 3. (a) 4. (b) 5. (a)[B] Define: 1. The method of preparing compost with the help of red worms is known as

vermicomposting. 2. The garbage collected in the garbage trucks is disposed in low lying open areas

knownaslandfills. 3. The waste product is called garbage. 4. The rotten garbage in soil is called compost.[C] Plastic is both useful and harmful. It helps in easy and durable storage of products.

It is very handy to use. Harmful effects of plastic usage are : (a) Environmental pollution (b) Harm to cattles/animals. (c) Choke drainage system.[D] Fill in the blanks : 1. Garbage 2. Gizzard 3. Animal waste 4. Composting

P-47GARBAGE IN, GARBAGE OUT



1. (c) 2. (c) 3. (d) 4. (d) 5. (a)

[B] Give one word :

1. Composting

2. Sewage

3. Landfill

4. Red worms

5. Radioactive waste

6. Garbage


1. Three ways to minimize over use of plastics :

(a) Reuse the bags wherever possible.

(b) Do not use plastic bags for storing eatables.

(c) Use recycled paper.

2. Tea leaves- decomposed

Piece of cloth – decomposed

Polythene bags – not decomposed

Broken glass – not decomposed

Fruit-vegetable peels - decomposed

Newspaper - decomposed

Iron nails - not decomposed

Paper bags – decomposed

3. Four things that can be reduce, reuse and recycle :

Paper, Plastic bottles, Polythene bags, Paper bags.

Documents

1 FOOD : WHERE DOES IT COME FROM