Author Archives: Rohit

1. Fill up the blanks in the following:
(a) The process of changing of water into its vapour is called_______________ .
(b) The process of changing water vapour into water is called_____________ .
(c) No rainfall for a year or more may lead to _____________ in that region.
(d) Excessive rains may cause__________ .
Ans:
(a) evaporation or vaporisation
(b) condensation
(c) droughts
(d) flood

2. State for each of the following whether it is due to evaporation or condensation:
(a) Water drops appear on the outer surface of a glass containing cold water.
(b) Steam rising from wet clothes while they are ironed.
(c) Fog appearing on a cold winter morning.
(d) Blackboard dries up after wiping it.
(e) Steam rising from a hot girdle when water is sprinkled on it.
Ans: 
(a) condensation
(b) evaporation
(c) condensation
(d) evaporation
(e) evaporation.

3. Which of the following statements are “true”?
(a) Water vapour is present in air only during the monsoon.
(b) Water evaporates into air from oceans, rivers and lakes but not from the soil.
(c) The process of water changing into its vapour is called evaporation.
(d) The evaporation of water takes place only in sunlight

(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.
Ans: 
(a) False
(b) False
(c) True
(d) False
(e) True.

4. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help you? If yes, how?
Ans: Yes, to dry the school uniform quickly, the uniform is spread near an anghiti or heater because evaporation is rapid at higher temperature. Higher the temperature faster is the rate of evaporation. So the uniform is dried up quickly.

5. Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?
Ans: The cooled water bottle has very cold exposed surface. Due to cool surface there is condensation of water-vapour from air on the surface of water bottle because water vapour is present in atmosphere. The condensed water molecules spread around the bottle. So a puddle of water is noticed after sometime.

6.To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet?
Ans: The breathe out gases contain water-vapour. The water-vapour condenses at spectacles so glass becomes wet and with the help of small amount of water, it is easy to clean the spectacles.

7. How are clouds formed?
Ans: The water present on the earth evaporates due to heating by the sun. The water vapour in the air condenses to form tiny droplets of water at high altitude, which appears as clouds. Thus clouds are formed by the condensation of water vapours present in air at high altitude.

8. When does a drought occur?
Ans: If there is no rain for a long period or for many years then there is scarcity of water in that region. This leads to drought.

Class 6 Science Chapter 14 VERY SHORT ANSWER TYPE QUESTIONS

1. Write the sources of water on the earth.
Ans:  Sources of water on the earth are:
Seas, Oceans, Rivers, Springs, Tubewells, etc.

2. In which forms, water exists on the earth?
Ans: Water exists on the earth in all three physical forms: ice, water and water vapour.

3. What is transpiration?
Ans: Loss of water in the form of water vapour through stomata of leaves is called transpiration.

4. How are the clouds formed?
Ans: Clouds are formed by the condensation of water vapour at high altitude.

5. What is meant by the conservation of water?
Ans: Careful, economical and wise use of water and avoiding the wastage of water is called conservation of water.

Class 6 Science Chapter 14 SHORT ANSWER TYPE QUESTIONS

1. Mention two main functions of water for living organisms.
Ans: Two main functions of water for living organisms are:
1. Water is essential for the germination of seeds, growth of plants and in photosynthesis.
2. Water is used for the transportation of people and goods.

2. Why is ocean water not suitable for domestic use?
Ans: Sea and ocean water contains large amounts of various salts. It is due to these salts the ocean water is salty and cannot be used for drinking, washing and for irrigation purposes.

3. Why does the water split on the floor disappear after some time?
Ans:  Due to evaporation the water split is changed into water vapour. So it disappears after some time.

4. How does heavy rain affect us?
Ans: Heavy rains may cause:
1. A rise of water level in dams, rivers, lakes, etc.
2. Waterlogging and floods.
3. Floods cause damage to property, crops and animals.

5. How does the failure of rainfall affect people on the earth?
Ans: The failure of rainfall can cause the following:
1.The soil becomes dry.
2. Water level in rivers, lakes, dams, etc. may fall. Ponds and canals may even dry up.
3. The ground water level falls.

6. Name two processes responsible for the formation of clouds.
Ans:  Evaporation and transpiration.

There are 4 containers A, B, C and D with same amount of water in each. Answer the following based on them.
(a) Name the container in which water will evaporate faster than all others.
(b) Name the container in which water will evaporate very slowly.
Give reason for your answer.
Ans.
(a) C – More is the exposed surface area, more will be evaporation of water.
(b) B – As it is closed, no evaporation takes place.

8. During winters why do we see more fog in close areas where there are lots of .trees?
Ans:  Due to lots of trees, air at that place contains much more water vapour during winters. These vapour condense on dust or smoke particles forming thick fog.

Class 6 Science Chapter 14 LONG ANSWER TYPE QUESTIONS

1. What is meant by conservation of water? Suggest three methods to conserve water.
Ans:  Careful and economical use of water and avoiding its wastage is called conservation of water.
Suggestions for conserving water:

1. Use only the required quantity of water.
2. Trees and forests help in causing rainfall. So to conserve water, we should plant more and more trees.
3. By collecting rainwater in tanks, ponds or by constructing check dams.

2. What is rainwater harvesting? Describe the method of rainwater harvesting.
Ans: Rainwater harvesting is the collection of rainwater and storing for future use. In this system rainwater in collected from the rooftops by means of pipes into storage tank for later use.
Methods of Rainwater Harvesting:

1. Rooftop rainwater harvesting. In this system, the rainwater from the rooftop is collected in a storage tank, through pipes.
2. Another method, a big pit is dug near house for collecting rainwater. This pit is filled with different layers of bricks, coarse gravels and sand or granite pieces.

1. Fill in the blanks in the following:
(i) Artificial magnets are made in different shapes such as_________ ,_______ and
(ii) The materials which are attracted towards a magnet are called_________
(iii) Paper is not a________
(iv) In olden days, sailors used to find direction by suspending a piece of
(v) A magnet always has ________poles.
Ans:
(i) bar magnet, horse-shoe magnet and cylindrical magnet
(ii) magnetic materials
(iii) magnetic
(iv) bar magnet or lode stone
(v) two or a pair of

2. State whether the following statements are true or false:
(i) A cylindrical magnet has only one pole.
(ii) Natural magnets were discovered in Greece.
(iii) Similar poles of a magnet repel each other.
(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
(v) Bar magnets always point towards North-South direction when suspended freely in air.
(vi) A compass can be used to find East-West direction at any place.
(vii) Rubber is a magnetic material.
Ans: 
(i) False
(ii) True
(iii) True
(iv) False
(v) True
(vi) True
(vii) False

3. It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.
Ans:  Iron is used to make some part of sharpener due to which it is attracted toward magnet.

4.  Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Ans:

5. Write any two properties of a magnet.
Ans:  Two properties of magnets are:
(i) A magnet has two poles: North pole and South pole.
(ii) Like poles repel each other and unlike poles attract each other.

6. Where are poles of a bar magnet located?
Ans: Poles are located at the ends of bar magnet just before the ends. These are north and south poles.

7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Ans: Take the bar magnet and suspend it freely with the help of a thread, the end that points towards north pole will be regarded as north end of the magnet. Take a bar magnet with known/marked poles on it. Let the north pole of the magnet be brought closer to the suspended magnet at the end that is pointing towards north, if it shows repulsion than it is confirmed.

8. You are given iron strip. How will you make it into a magnet?
Ans:  Making a magnet: Take an iron strip and place it on the table. Now take a bar magnet and place one of its poles near one edge of the strip of iron. Without lifting it move it along the length of the iron strip till you reach the other end. Now lift the magnet and bring the pole to the same point of strip from where yob began. Repeat this process about 30-40 times. Bring some iron fillings near the strip and observe that the strip attracts the fillings. This indicates that the iron strip becomes magnet.

Remember that the pole of magnet and direction of its movement should not change.

9. How is compass used to find direction?
Ans: A compass is a small case of glass. A magnetised needle is pivoted inside the box. The needle can rotate freely. Compass also has a dial with directions marked on it. The compass is kept at the place where we want to know the directions. When the needle comes to rest it indicates north-south direction. The compass is then rotated until the north and south marked on the dial are at the two ends of the needle. Usually different colours are used to point the ends of needle to identify the north and the south poles.

10. A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Effect observed in each case is stated in Column I. Possible reason for the observed effects are mentioned in Column II. Match the statements given in Column I with those in Column II. 

Ans:

Class 6 Science Chapter 13 VERY SHORT ANSWER TYPE QUESTIONS

1. Name the compound of iron contained in lode stone.
Ans: The compound of iron is iron oxide or magnetite.

2. Name the shepherd after which magnet was named.
Ans: Magnets.

3. How can you separate a magnetic substance from a mixture?
Ans: By using a bar magnet, the magnetic substance is separated from mixture.

4. At which place on a magnet, its magnetic force is maximum?
Ans: At poles.

5. In which direction does a suspended magnet come to rest?
Ans: Magnet comes to rest in N-S (north-south) direction.

6. What happens when N-pole of a magnet is brought near the N-pole of a suspended magnet?
Ans: There is repulsion between these two magnets as there is repulsion between like poles.

Class 6 Science Chapter 13 SHORT ANSWER TYPE QUESTIONS

1. Draw the diagram of (a) Bar magnet (b) Horse-shoe magnet.
Ans:

2.Identify magnetic and non-magnetic substances from the list given below: Iron, Steel, Nickel, Plastic, Wood, Copper and a Stainless Steel spoon
Ans:

3. Draw a diagram of a magnetic compass.
Ans:

4. Write main properties of a magnet.
Ans: (i) Magnet has two poles—south pole and north pole.
(ii) Poles of magnet cannot be isolated.
(iii) Like poles repel each other and unlike poles attract each other.
(iv) Freely suspended magnet aligns in N-S direction.

5.Write two methods by which a magnet can be demagnetised.
Ans: (1) By hammering the magnet strongly.
(2) By heating a magnet strongly and keeping it in the east-west direction.

6. It is advised to keep the magnets away from television, mobiles, CD and computers Explain why?
Ans: Television, mobiles, CD, computers and many more devices are made up of magnetic materials and magnets in it. If you bring a magnet closer to it then it will spoil these devices.

7. Few iron nails and screws got mixed with the wooden shavings while a carpenter was working with them.How can you help him in getting the nails and screws back from the scrap without wasting his time in searching with his hands?
Ans: With the help of a magnet we can attract all iron nails and screws and can separate them from the wooden shavings. As iron nails and screws are magnetic materials and will get attracted to the magnet,whereas wooden shavings are non-magnetic.

8. It is said that repulsion is a sure test for magnetism. Why is it so?
Ans: To identify the magnet, repulsion (like poles of two magnets repel) is the only test which will let you know whether the given rod is an iron rod or a bar magnet. Because a magnet attracts an iron object and unlike poles of magnets also attract each other.

9. A given bar magnet was broken into pieces. Where will be its North and South pole?

Ans: If you cut a bar magnet into pieces then the end labelled as North remains north and the other end formed will be south. Similarly the end that was pointing south will be south pole and its opposite end will be the new north pole.

10. You are given two rods. Out of these, one is an iron rod and the other one is magnet, how will you identify these rods?
Ans: Take both the rods and suspend them separately. Bring one end of a bar magnet close to both the ends of the suspended rod. If it shows attraction at both the ends then it is an iron rod. If it shows attraction at one end and repulsion at the other end then it is a bar magnet.

Class 6 Science Chapter 13 LONG ANSWER TYPE QUESTIONS

1. Show that a magnet has two poles. What are the properties of the poles of a magnet?
Ans. We know that pole is the point where the strength of the magnet is maximum. So more and more iron particles will be attracted at poles of a magnet when we bring a magnet near the iron particles. We will observe the crowdness of particles at the ends of magnet. This indicates the presence of two poles in a magnet. Hence poles are present in a magnet in pair. If a magnet is divided into two parts, each part also possesses a pair of poles.

1. Fill in the blanks:
(a) A device that is used to break an electric circuit is called_______________
(b) An electric cell has___________
Ans:
(a) switch
(b) two

2. Mark ‘True’ or ‘False’ for the following statements:
(a) Electric current can flow through metals.
(b) Instead of metal wires, a jute string can be used to make a circuit.
(c) Electric current can pass through a sheet of thermocol.
Ans:
(a) True
(b) False
(c) False.

3.Explain why the bulb would not glow in the arrangement shown in fig

Ans: The bulb would not glow in the arrangement shown in figure because the one end of tester/screw driver is made up of plastic which does not allow the electric current to flow through it.

4. Complete the drawing shown in Fig. 12.9 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Ans:

5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Ans: Electric switch is used to make electric circuit open or closed for a particular appliance and hence with the help of a switch we can use an appliance according

6. Would the bulb glow after completing the circuit shown in Fig. 12.9 if instead of safety pin we use an eraser?
Ans: No, since eraser is an insulator so it does not allow the current to pass. Hence the bulb will not glow.

7. Would the bulb glow in the circuit shown in Fig. 12.11.

Ans: Yes, the electric circuit is closed so the bulb will glow.

8. Using the“conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.
Ans: Yes, if the object is good conductor of electricity then current will pass through conduction tester and the bulb will glow. Hence the object will be a conductor of electricity.

9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Ans: Our body is good conductor of electricity and rubber is insulator. During repairing work if the body comes in contact with current carrying wire then there will not be any accident as rubber does not allow the passage of current through it. Hence electrician uses rubber gloves while repairing an electric switch.

10. The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?
Ans: Plastic or rubber is an insulator which does not allow electric current to pass through it. The handles of the tools like screwdrivers and pliers used by electricians for repair have covering of plastic or rubber so that electric current may not pass through these tools to the body of the electrician to harm him.

Class 6 Science Chapter 12 VERY SHORT ANSWER TYPE QUESTIONS

1. What is the direction of flow of current in a dry cell?
Ans: . The current flows in closed circuit from +ve to -ve terminal of cell.

2. Name the +ve terminal of dry cell.
Ans:. Carbon rod with a metal cap on it.

3. Name the -ve terminal of a dry cell.
Ans:  Zinc metal plate.

4. What is dry cell?
Ans:  It is a device which converts chemical energy into electrical energy.

5. What is solar cell?
Ans: A device which converts solar energy into electrical energy.

6. What is open circuit?
Ans:  An electric circuit in which electrical contact at any point is broken is called open circuit.

7. Write one use of insulators.
Ans: Insulators are used in making switchboard, handles of testers, screw drivers.

8. What is the name of thin wire in the electric bulb?
Ans: Filament.

Class 6 Science Chapter 12 SHORT ANSWER TYPE QUESTIONS

1. Mention two advantages of a dry cell.
Ans: 
1. It converts chemical energy into electrical energy.
2. It is light and small in size.

2. Draw a diagram showing the two terminals of a bulb.
Ans:

3. Draw the circuit diagram for operating a bulb with the help of a dry cell.
Ans:

4. Define conductors and insulators. Give one example of each.
Ans:  A conductor is that which easily allows the passage of current through it. Example: Aluminium or any metal.
An insulator is that which does not allow the passage of current through it. Example: Rubber.

5. Identify conductors and insulators from the following:Eraser, paper, matchstick, copper wire, pencil lead, polythene
Ans: Conductors: Copper wire, pencil lead.
Insulator. Eraser, paper, matchstick, polythene.

6. Name the scientist who invented electric cell and the scientist who invented electric bulb.
Ans: Electric cell: Alessandro Volta.
Electric bulb: Thomas Alva Edison.

7. Give one activity to prove that air is an insulator.
Ans: Take an electric circuit, keep the terminals unconnected in the air. The bulb do not glow, as air is an insulator and does not allow the current to flow through it.

8. In any electric circuit, when the switch is on and the current flows through it why do the wire, switches, bulb or devices become hot?
Ans.: This is because electric energy changes into heat energy.

9.The headlights of a car have reflectors behind the bulb. What is the function of reflectors?
Ans: The reflector helps in reflecting the light into a focussed area.

10.If you touch an electric wire carrying current you get a shock, but if on the same wire the birds sit they do not get any shock/current. Explain why?
Ans: When we hold the wire carrying current then the circuit is closed and the current flows from our body and enters earth but the birds sitting on the same wire do not get any current as the circuit is not complete. If the bird touches the earth wire, it will also die due to electric shock.

Class 6 Science Chapter 12 LONG ANSWER TYPE QUESTIONS

1.(1)What is electric circuit?
(2)How many types of electric circuit are there? Define them.
(3)Draw a diagram to show the closed circuit for switch, bulb and dry cell.
Ans: 
(1)The diagram that shows the path of electric current is called electric circuit.
(2)There are two types of electric circuit:
(a) Open electric circuit
(b) Closed electric circuit
(a)Open electric circuit: The circuit in which electrical contact at any point is broken is called open electric circuit.
(b)Closed electric circuit: The circuit in which electric current flows from one terminal of a cell or battery to the other is called a closed circuit.

NCERT Solutions

1. Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

Ans:

2. Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the fame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.
Ans:

3. Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?
Ans: Yes, there are many things which give a circular shadow if held in one way and a rectangular shadow if held in another way. For example: a cylinder, a circular disc etc.

4. In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?
Ans: No, in a completely dark room no image will be formed because there is no light in the room so no reflection of light takes place and no image will be formed.

Class 6 Science Chapter 11 VERY SHORT ANSWER TYPE QUESTIONS

1. Whether the moon is luminous or non-luminous body?
Ans: Moon is non-luminous body.

2. What is umbra?
Ans: Umbra is the dark region behind object facing light which does not receive light at all.

3. How does a light ray travel?
Ans: Light ray travels in a straight line.

4. Give one natural source of light. 
Ans: Sun is a natural source of light.

5. What is shadow? 
Ans: Shadow is the dark space behind an opaque object where light does not reach.

6. What is penumbra?
Ans: The less darker shadow formed penumbra.on the periphery of dark shadow is called penumbra.

Class 6 Science Chapter 11 SHORT ANSWER TYPE QUESTIONS

1. State difference between a luminous and a non-luminous body.
Ans: The bodies which emit light are called luminous bodies. Example: sun, stars, burning candle etc.
The bodies which does not emit light are called non-luminous bodies. Example: moon, earth, blackboard.

2. Why is the moon not considered as a luminous body?
Ans: Moon is non-luminous body because it shines by reflecting the sunlight falling on it.

3. What is an incandescent body? Give example.
Ans:  The bodies which emit light when heated to a very high temperature are called incandescent bodies. Example: electric bulb.

4. When does a shadow form?
Ans: Shadow is formed when light does not reach behind the opaque object kept in the path of light

5. Draw a diagram to illustrate the formation of umbra and penumbra.
Ans: 

6. What are the essential conditions for the formation of shadow?
Ans:
(1) There should be an opaque material.
(2) There should be a source of light and screen.
The object must be placed in the path of light. Then shadow is formed on the screen.

7. Define reflection of light.
Ans: When light rays after striking the smooth and shiny surface return to same medium, this phenomenon is called reflection of light.

8. Write difference between shadow and image.
Ans: 

9. How will you convert a glass sheet into a translucent sheet?
Ans: There are following two methods to convert glass sheet into a translucent sheet:
(i) By smearing a thin layer of oil on glass sheet.
(ii) By covering a side of sheet by butter paper.

10. What is shadow? How does the colour of an opaque object affects the colour of the shadow?
Ans: A dark outline or patch formed by an opaque object that blocks light coming from a source of light is called shadow. The colour of an opaque object does not affect the colour of the shadow.

11. Write the differences between umbra and penumbra.
Ans: 

12. What do we need in order to see a shadow?
Ans: We need: (i) A source of light (ii) a screen (in) an opaque object.

13. What do you mean by scattering of light?
Ans: When a beam of light falls on a rough surface it is turned back in different directions. It is called scattering of light.

14. A and B are facing the mirror and standing in such a way that A can see B and B can see A. Explain this phenomenon.

Ans:  The light rays from A falls on the mirror and gets reflected and reaches B, the light from B falls on the mirror and reflects to reach A. The path of light is just reversed as shown.

15. ‘X’ is 20 cm away from the mirror. If he moves few steps closer to the mirror what will happen to the image

Ans: The size of the image will be same as the size of the object.

16.Write the mirror image of ‘SMART’?
Ans: THAM8

17. Have you ever seen an ambulance? It is written in the form of mirror image on vehicles. Explain why it is done so and give the mirror image of AMBULANCE.
Ans:  The mirror image of AMBULANACE is aovt/yuaMA.
It is written so on the vehicles for the people to see in their rear view mirrors, read it correctly and immediately give way to the vehicle as it carries patients who need urgent medication.

18. You have to cost the shadow of your pencil on the wall with the help of candle in a dark room. How can you obtain the shadow of same size, small size and big size of the same pencil?
Ans: (a)The shadow of the pencil will be small when the pencil is taken close to the wall and away from the candle.
(b)The shadow will be big in size when the pencil is taken closer to the candle.
(c)To get the same sized shadow as the pencil is, adjust the distance between the wall, pencil and candle at equal distances.

Class 6 Science Chapter 11 LONG ANSWER TYPE QUESTIONS

1. What is reflection of light? Explain reflection of light with the help of an activity.
Ans:  When light rays fall on a highly polished (e.g. mirror) smooth surface and return to the same medium, it is called reflection of light.
Activity to show reflection of light: This activity should be done at night or in a dark room. Ask your friend to hold a mirror in his hand at one corner of the room. Stand at another comer with a torch in your hand. Cover the glass of torch with your fingers and switch it on. There should be small gap between your fingers. Direct the beam of torch-light on to the mirror that your friend is holding. Adjust the direction of torch so that patch of light falls on your friend standing in the room. This activity shows the reflection of light also that light travels in straight line.

2. Explain the manner in which light travels with the help of an activity.
Ans: Take a comb and fix it on one side of a thermacol sheet. Fix a mirror on the other side as shown in figure. Spread a dark coloured sheet of paper between the mirror and the comb. Send a beam of light from a torch through the comb. You get a pattern of light similar to that shown in figure. This activity explains the manner in which light travels and gets reflected from a mirror.

3. Explain that light has the property of rectilinear propagation.
Ans: We take three pieces of cardboard. Place them one on the top of one another and make a hole in the middle of each cardboard by using a thick nail. Erect these cards up on the table at a short distance away from each other. Take a candle which is of the same height as the holes in the cards. Light the candle and place it in front of the cards. We see that the light of candle is visible only when the holes on cards lie in a straight line. If we disturb them the light of candle disappears. This experiment shows that light propagates in a straight line.

1. Give two examples each of modes of transport used on land, water and air.
Ans:
(i) Land—Bus, truck, train.
(ii) Water—Ship, boat.
(iii) Air—Aeroplane, Helicopter.

2. Fill in the blanks:
(i) One metre is___________
(ii) Five kilometre is___________
(iii) Motion of a child on a swing is_____________ .
(iv) Motion of the needle of a sewing machine is_______________ .
(v) Motion of wheel of a bicycle is_____________ .
Ans:
(i) 100
(ii) 5000
(iii) periodic (oscillatory) motion
(iv) periodic oscillatory (v) circular.

3. Why can a pace or a footstep not be used as a standard unit of length?
Ans: Because a pace or a footstep of each and every person is not equal.

4. Arrange the following lengths in their increasing magnitude :
1 metre, 1 centimetre, 1 kilometre, 1 millimetre.
Ans: Ascending order of length:
1 millimetre < 1 centimetre < 1 metre < 1 kilometre

5. The height of a person is 1.65 m. Express it in cm and mm.
Ans:
(a) 1.65 m, as one metre = 100 cm
= 1.65 x 100 cm = 165 cm
(b)65 x 100 x 10 mm = 1650 mm.

6. The distance between Radha’s home and her school is 3250 ,m. Express this distance in km.
Ans:

7. While measuring the length of a knitting needle, the reading of the scale at one  end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?
Ans:  Length of the needle = 33.1 cm – 3.0 cm = 30.1 cm.

8. Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.
Ans: 
(i) Similarity: Both the wheel of a bicycle and a ceiling fan exhibit motion on a fixed axis.
(ii) Dissimilarity: Bicycle moves forward thus executes rectilinear motion but fan does not show such motion.

9. Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?
Ans:  An elastic measuring tape gives incorrect length of the distance between two points.
Reasons:
(i) The length of the elastic tape varies and depends upon the force by which it is stretched.
(ii) Measurement would vary between 2 or 3 readings even when measured by the same person and by the same elastic tape.
(iii) Measurement would also vary if different persons measure the same distance.

10. Give two examples of periodic motion.
Ans:
(i) Oscillations of a pendulum.
(ii) Motion of swing/motion of earth round the sun.

Class 6 Science Chapter 10 VERY SHORT ANSWER TYPE QUESTIONS

1. Are senses reliable for accurate measurement?
Ans: Our senses are not reliable for accurate measurement.

2. Why can hand span and arm length not be used as standard units of length?
Ans: because these vary from person to person.

3. How many centimetres are there in 1 m?
Ans: 100 cm.

4. Name the measuring device which can be used for measuring the girth of a tree.
Ans: Measuring tape.

5. Give one example of linear motion.
Ans: Motion of stone falling from a certain height.

6. Give an example of circular motion.
Ans: Motion of arms of watch.

7. Name the types of motion in which a body moves along a straight path
Ans: Rectilinear or linear motion.

8.Find the length and breadth of given rectangle in mm and cm.

Ans: Using measuring scale (15 cm scale), Length AB = 3 cm and breadth BC = 2 cm.
AB = 3 x 10 = 30 mm
BC = 2 x 10 = 20 mm.

9.Give the unit for measuring the following:
(a) Distance between Delhi and Jaipur.
(b) Thickness of a coin.
(c) Length of your eraser.
(d) Length of your shoe lace.
Ans: 
(a) Kilometre
(b) Millimetre
(c) Centimetre
(d) Centimetre

10. Name the device used to measure the following:
(a) Size of your shoulder.
(b) Size of your wrist.
(c) Your height.
(d) Your weight.
(e) Cloth for curtain.
(f) Circumference of round table.
Ans: 
(a) Measuring tape
(b) Measuring tape
(c) Measuring tape
(d) Weighing balance
(e) Metre scale or measuring tape
(f) A long thread or measuring tape.

Class 6 Science Chapter 10 SHORT ANSWER TYPE QUESTIONS

1. State two precautions to be observed while measuring length with the help of a metre scale.
Ans:  Two precautions are:
(i) The initial point of distance must coincide with the zero reading of metre scale.
(ii) The eye should be kept in line with the point of measurement.

2. Define rest and motion.
Ans:  The objects which do not change their positions with time are said to be at rest. The objects which change their positions with time are said to be in motion.

3. Define the term standard unit.
Ans:  The unit that could be used everywhere as a basic unit of measurement is called a standard unit.

4. How can a measured length be expressed?
Ans: Each measurement has:
(i) A number describing the numerical value.
(ii) The unit in which that quantity is measured.

5. Give one example each of the following types of motion:

(a) Linear
(b) Translation
(c) Circular
(d) Periodic.
Ans:
Types of motion                  Example
(a)  Linear                                  motion of stone falling
(b)  Translatory                         buses
(c) Circular                                 ceiling fan
(d) Periodic                                pendulum of   clock

Class 6 Science Chapter 10 LONG ANSWER TYPE QUESTIONS

1. Why do we need standard unit for measurement?
Ans: We need standard unit for measurement to make our judgement more reliable and accurate. For proper dealing, measurement should be same for everybody. Thus there should be uniformity in measurement. For the sake of uniformity we need a common set of units of measurement, which are called standard units. Nowadays SI units are used in science and technology almost universally.

2. What type of motion do the following objects have?
(a) the galloping of a horse
(b) the needle of a sewing machine
(c) the movements of a mosquito
(d) the blades of an electric fan
(e) the smoke from a lighted dhoopbatti
(f) wheels of moving car.
Ans:
(a) The galloping of a horse: Linear motion.
(b) The needle of a sewing machine: Periodic motion.
(c) Movement of a mosquito: Random motion.
(d) Blade of an electric fan: Circular motion.
(e) The smoke from a lighted dhoopbatti: Random motion.
(f) Wheels of moving car: Linear motion and Rotational motion.

3. Give two examples for each of the following motions:
(i) Linear motion
(ii) Spinning motion
(iii) Oscillatory motion
(iv) Periodic motion 
(v) Vibrational motion
(vi) Circular motion
(vii) Random motion
Ans: 
(i) Linear motion: (a) Rolling of ball on ground, (b) Moving of bicycle on road,
(ii) Spinning motion: (a) Rotating fan, (b) Wheel of sewing machine.
(iii) Oscillatory motion: (a) Pendulum of clock, (b) Motion of a child on a swing,
(iv) Periodic motion: (a) Pendulum of clock, (b) Motion of a swing, heartbeat.
(v) Vibrational motion: (a) String of a guitar, (b) Surface of drums.
(vi) Circular motion: (a) Rotation of fan, (b) Bicycle wheel.
(vii) Random motion: (a) Motion of football players, (b) Movement of mosquito.

1. What is a habitat?
Ans: The surroundings where animals live is called their habitat. The organisms depend on their habitat for their food, water, air, shelter and other needs. Habitat means a dwelling place.

2. How are cactus adapted to survive in a desert?
Ans: Cactus are adapted to survive in a desert as they have
(i) No leaves or spiny leaves to prevent water loss through transpiration.
(ii) Stem is modified in such a way that it performs photosynthesis and conserves water.
(iii) Their roots go very deep into the soil for absorbing water.

3. Fill in the blanks:
(a) The presence of specific features which enables a plant or an animal to live in a particular habitat is called___________ .
(b) The habitats of the plants and animals that live on land are called _________________ habitats.
(c)The habitats of plants and animals that live in water are called ____________________ habitats.

(d) Soil, water and air are the____________ factors of a habitats.
(e) Changes in our surroundings that make us respond to them are called
Ans: 
(a) adaptation
(b) terrestrial
(c) aquatic
(d) abiotic
(e) stimuli

4. Which of the things in the following list are non-living?
Ans: Plough, Mushrooms, Sewing machine, Radio, Boat, Water, Hyacinth, Earthworm. Plough, Sewing machine, Radio, Boat and water are non-living.

5. Give an example of a non-living thing which shows any two characteristics of living thing.
Ans: Example of non-living thing is cloud which shows following two characteristics of living things:
(i) It grows in size
(ii) It shows movement.

6. Which of the following non-living things were once part of a living thing?
Butter, Leather, Soil, Wool, Electric Bulb, Cooking Oil, Salt, Apple, Rubber.
Ans: Butter, Leather, Wool, Cooking oil, Apple and Rubber are the non-living things which were once part of a living thing.

7. List the common characteristics of living things.
Ans: Some common characteristics of living things are:

1. Growth
2. Movement
3. Reproduction
4. Respiration
5. Responsiveness
6. Excretion

8. Explain why speed is important for survival in the grasslands for animals that live there. (Hint: There are few trees or places for animals to hide in grasslands habitats).
Ans: In grasslands habitats, there are few trees or places for animals to hide. When their enemy attacks they have to run faster so as to reach a safe place. If they fail, they lose their life. So, the speed is very important for survival of grassland animals.

Class 6 Science Chapter 9 VERY SHORT ANSWER TYPE QUESTIONS

1. Name some plants found on mountains.
Ans: Oaks, Pinus and Deodars.

2. What is habitat?
Ans:. The place where organisms live and which provide food and safety for them is ‘called habitat.

3. Name a few habitats.
Ans: Forests, grassland, mountains, ponds and oceans etc.

4. Name two organisms that live in deserts.
Ans:  Cactus, camel, desert rat.

5. Name a few plants that live in ponds.
Ans:  Hydrilla, lotus, hyacinth etc.

6. Name the habitat where various types of fish live.
Ans:  Pond, river, sea.

7. Name a common thing in all fishes.
Ans:  Gills, streamlined body, fins, tail.

8. What is the function of gill?
Ans: Gills help the fish to absorb oxygen dissolved in water.

9. Name the animal which is called the ship of desert.
Ans: Camel

10. Name various types of habitat.
Ans:
(i) Terrestrial Habitats
(ii) Aquatic Habitats
(iii) Aerial Habitat

11. Name two aquatic animals.
Ans:
(i) Fish
(ii) Tortoise

12. Name two terrestrial organisms.
Ans:
(i) Cat
(ii) Dog

13. Name two examples of aerial habitat animals.
Ans:
(i) Birds
(ii) Mosquitoes

14. Name the types of components of habitat.
Ans: Components of habitat are:
(i) Biotic components
(ii) Abiotic components

15. Give two examples of each biotic and abiotic components.
Ans: Plants and animals are biotic components, air and water are abiotic components.

16. What do you mean by germination of seeds?
Ans: The beginning of a new plant from the seeds is called germination.

17. Does adaptation take place in a short time?
Ans: No, adaptation does not take place in a short time. It takes place in thousands of years.

18. Name few terrestrial habitats.
Ans: Deserts, mountains and grassland.

19. Name some aquatic habitats.
Ans:Oceans, ponds and lakes.

20. What are predators?
Ans: The animals which kill other animals for their food are called predators.

21. What is a prey?
Ans: The animals which are killed by predators for their food are called prey.

22. Name two aquatic animals which have no gills.
Ans: Dolphin and whales.

23. What are blowholes?
Ans: The organs by which dolphin or whales breathe are called blowholes or nostrills.

24. What is photosynthesis?
Ans: The process by which plants make their own food with the help of chlorophyll,sunlight, carbon dioxide and water is called photosynthesis.

25.What is the main Junction of food?
Ans: Food gives energy to the organism which helps them in growth and development.

26. What is breathing?
Ans:  The process of taking in oxygen and giving out carbon-dioxide (inhalation and exhalation of air) is called breathing.

27. What is respiration?
Ans: The process in which oxygen is used by the living bodies to break down food to get energy, water and carbon dixode is produced is called respiration.

28. What is stimuli?
Ans: The changes in our surroundings that makes us respond to them are called stimuli.

29. What is excretion?
Ans: The process of getting rid of the waste by the living organisms is known as excretion.

30. Do plants also excrete?
Ans: Yes, plants also excrete.

31. What is reproduction?
Ans: The process by which living organisms produce more of their own kind is called reproduction.

32. Do animals move?
Ans: Yes, animals move from one place to another.

33. Do plants also move?
Ans:  Plants are generally fixed in the soil so they do not move from one place to another.

Class 6 Science Chapter 9 SHORT ANSWER TYPE QUESTIONS

1. What are the differences in the desert and sea regions?
Ans: In the sea, plants and animals are surrounded by salty water. Most of them use the air dissolved in water for breathing. In desert, a very little amount of water is available. It is very hot in the day time and very cold at night. The organisms breathe air from the surroundings.

2. What do you mean by term adaptation?
Ans: The presence of specific features or certain habits which enable a plant or an animal to live in its surroundings is called adaptation.

3. Explain the features offish which help it to adapt to live in water.
Ans:
(i) The shape of the fish is streamlined which help in the movement.
(ii) The slippery scales/skin on their bodies to protect them.

(iii) They have flat fins and tails which help them to swim, change direction and to keep the body balanced.
(iv) They have gills which help in breathing in water.

4. How are camels adapted to live in desert?
Ans: (i) The feet of the camels have thick, flat large soles which help them in the movement on sand.
(ii) They can live without water for a long time. When water is available, it drinks large amount of water at a time.
(iii) They release very little urine to prevent loss of water.
(iv) Their dung is also dry which also helps to prevent loss of water.
(v) The long legs of camel helps to keep the body away from the heat of the sand.

5. What do you mean by acclimatisation?
Ans: The small changes which take place in the body of a single organism over short periods to overcome small problems due to changes in the surroundings are called acclimatisation.

6. Why do we need abiotic factors?
Ans: The abiotic factors like air, water, light and heat are very important for the growth of plants. These abiotic factors are also very important for the growth and the development of animals.

7. How are some animals adapted to live in desert?
Ans: Some animals like rats and snakes do not have the long legs like camels to stay away from the effect of heat during the day. They stay in burrows deep in the sand. They come out only during the night.

8. Write the features of desert plants.
Ans: 
(i) The leaves in desert plants are either absent or very small.
(ii) Leaves are converted into spines which help to reduce loss of water.
(iii) The stems become thick, flat and green which help in photosynthesis.
(iv) The stem is covered with waxy layer which helps to retain water. In some plants stem is spongy and stores water.
(v) The roots go very deep in the soil to absorb water.

9. Explain the adaptation of trees to live in mountain regions.
Ans:
(i) The shape of the trees is of normally cone type.

(ii) Branches are sloping.
(iii) The leaves of these trees are needle like.
(iv) These structures prevent accumulation of rainwater and snow over them.

10. Explain the adaptation of animals to live in mountain region.
Ans: 
(i) The animals have thick skin or fur to protect them from the cold.
(ii) Some animals have thick fur on their body, feet and toes which protect them from cold on walking in the snow.
(iii) The goats have strong hooves for running up on rocky slopes.

11. Explain the adaptation of plants to live in water.
Ans: 
(i) Roots are reduced in size which hold the plant.
(ii) Stems are long, hollow and light.
(iii) Stems grow up to the surface of water.
(iv) Leaves and flowers float on the surface of water.
(v) The leaves are covered by the waxy layer which protects the leaves from excessive water.

12.What kind of movement do we see in plants?
Ans:
(i) Opening and closing of a flower.
(ii) Growth of a stem and leaves.
(iii) Movement of water, minerals and food from one part of the plant to other.
(iv) Movement of stem towards sunlight and root towards water in the soil.

13. Frogs can live both on land and in water, name the adaptations seen in these animals.
Ans: Frogs have strong back legs that help them in leaping and catching their prey. They have webbed feet which help them to swim in water.

Class 6 Science Chapter 9 LONG ANSWER TYPE QUESTIONS

1.Explain the characteristics oflimng organisms.
Ans. There are following characteristics of living organisms
(i) All living organisms require food. The food gives energy for growth and to maintain other life processes.
(ii) All living organisms show growth. Young ones of animals grow into adults. Plants also grow.
(iii) All living organisms respire. In respiration oxygen is used for the oxidftion of food and carbon dioxide is produced.
(iv) All living organisms respond to stimuli. All plants and animal respond to light, heat and the changes around them.
(v) All living organisms show excretion. The process of getting rid of waste product by the living organisms is called excretion. Plants also remove their wastes.
(vi) All living organisms reproduce. The process by which plants and animals produce their own kind is called reproduction.

2.Write the difference between living and non-living things.
Ans.

1. Fill in the blanks:
(a) Joints of the bones help in the_____________ of the body.
(b) A combination of bones and cartilages forms the_______________ of the body.
(c) The bones at the elbow are joined by a______________
(d) The contraction of the____________ pulls the   bones  during  
Ans: 
(a) movement
(b) skeleton
(c) hinge
(d) muscle

2. Indicate ‘true’ and false’ among the following sentences:
(a) The movement and locomotion of all animals is exactly the same.
(b) The cartilages are harder than bones.
(c) The finger bones do not have joints.
(d) The fore arm has two bones.
(e) Cockroaches have an outer skeleton.
Ans: 
(a) False
(b) False
(c) False
(d) True
(e) True

3. Match the items in column I with one or more items of column II:

Ans:

4. Answer the following questions:
(a) What is a ball and socket joint?
(b) Which of the skull bones are movable?
(c) Why can our elbow not move backwards?
Ans:
(a) The rounded end of one bone fits into the hollow space of other bone. This is called ball and socket joint. Ball and socket joints allow movements in all the directions, e.g. shoulder and hip can be moved in all directions.
(b) In skull, only lower jaw is movable.
(c) Our elbow cannot move backwards because the elbow has a hinge joint that allows movement in only one direction.

Class 6 Science Chapter 8 VERY SHORT ANSWER TYPE QUESTIONS

1. What do you mean by movement?
Ans:  The changing position of the body or any part of the body is called movement.

2. At which part does the arm rotate?
Ans: The arm rotates on the round pit-like structure.

3. If you tie a scale with your arm, are you able to bend your elbow?
Ans: No, we cannot bend our elbow.

4. Name the places where two parts of the body are seen to be joined together.
Ans: These places are called joint.

5. If there are no joints then will it be possible to move?
Ans: No, it is not possible.

6. Can bones be bent?
Ans:  No, bones cannot be bent.

7. Can we bend our body at every part?
Ans: No, we can bend our body only at joints.

8. How many types of joints are there?
Ans: There are five types of joints in our body.

9. Name the various types of joint.
Ans: 
(i) Ball and socket joints
(ii) Pivotal joints
(iii) Hinge joints
(iv) Fixed joints
(v) Gliding joints

10. What is cavity in bone?
Ans:  The hollow space in the bone is called cavity.

11. Give two examples of ball and socket joint.
Ans: 
(i) Joint of upper arm and shoulder.
(ii) Joint of thigh and the hip.

12. Give an example of pivotal joint.
Ans. The joint of skull with backbone.

13. Give two examples of hinge joints.
Ans:
(i) Joints in fingers
(ii) Joints in knee

14. Give an example of fixed joint.
Ans: Joint of cranium skull.

15. Give an example of gliding joint.
Ans: The joint in backbone.

16. What is skeleton?
Ans: The framework of bones in our body is called skeleton.

17. What are ribs?
Ans: The bones of the chest are called ribs.

18. What is rib cage?
Ans: Ribs are joined with backbone to form a box. This box is called rib cage.

19. What are shoulder bones?
Ans: The shoulder bones are formed by the collar bone and the shoulder blade. It connects the upper part of the chest and bones of the arm.

20. What are pelvic bones?
Ans: The bones which enclose the body part below the stomach are called pelvic bones.

21. What are cartilages?
Ans: Some additional parts of the skeleton which are not as hard as bones and are elastic in nature and can be bent are called cartilages, e.g. cartilage of ear.

22. Name the three components of skeleton.
Ans: Skeleton is made up of many bones, joints and cartilage.

23. Name the parts of the body which help in movement.
Ans: Contraction and relaxation of muscles and bones and joints help in movement.

24. Name two animals which move without bones.
Ans: (i) Earthworm      (ii) Snail

25. Give an example of animal which can walk, climb and fly in the air.
Ans: Cockroaches.

26. Name the organ in cockroach which helps in walking.
Ans: The three pairs of legs in cockroach help in walking.

27. Which part of the cockroach help in flying?
Ans: There are two pairs of wings attached to the breast which help them in flying.

28. Name a bird which can swim in water.
Ans. Duck.

29. What do you mean by streamlined?
Ans: If the body tapers at both the ends then such, shape of the body is said to be streamlined.

30.How does the snake move?
Ans: Snakes have a long backbone and many thin muscles which help in the movement. The snake’s body curves into many loops. Each loop of the snake gives it a forward push by pressing against the ground.

31. What do you mean by fractured bone? 
Ans: Fractured bone means broken bone.

32. Why are fractured bones plastered?
Ans. Plaster keeps broken bones at their right place so that they grow and join properly.

33. Name organs that are protected by the rib cage?
Ans: Heart and Lungs.

34. Why do we need two muscles together to move a bone?
Ans: A muscle can only pull, it cannot push. Thus, two muscles are required to work together to move a bone. When one muscle contracts, the bone is pulled. When another muscle of the pair pulls, it brings the bone in its original position.

35. Name three animals that have streamlined body.
Ans: Fish, Birds, Snake.

36. Many people suffer from a problem called arthritis. Explain its connection with movement.
Ans: Arthritis is the pain in joints. With this problem people find difficulty in moving from one place to another.

37. How is a bird’s body adapted for flying?
Ans: The following adaptations are seen in the body of birds.
(i) Bones are hollow.
(ii) Forelimbs are modified into wings.
(iii) Body is streamlined.

Class 6 Science Chapter 8 SHORT ANSWER TYPE QUESTIONS

1. What are joints? Write the names of various types of joints.
Ans: The places where two parts of the body seem to be joined together are called joints. There are following types of joints:

1. Ball and socket joints
2. Pivotal joints
3. Hinge joints
4. Fixed joints
5. Gliding joints

2. What is skeleton? Draw a diagram to show the human skeleton.
Ans: The bones in our body form a framework to give a shape to the body. The framework is called skeleton

3. Write two ways by which we may know the shape of human skeleton.
Ans:
(i) We can know the shape of skeleton by feeling.
(ii) We could know the shape by X-ray images of human body

4:Write the differences between bones and cartilage.
Ans:  

5. How do the muscles work?
Ans: The muscles work in pairs. When one of them contracts, the bone is pulled in that direction, the other muscle of the pair relaxes. To move the bone in the opposite direction, the relaxed muscle contracts to pull the bone towards its original position, while the first relaxes.A muscle can only pull. It cannot push.

6. How does the earthworm move?
Ans:  Earthworm does not have bones. It has muscles. During the movement, earthworm first extends front part of the body keeping the rear portion fixed to the ground. Then it fixes the front and releases the rear end. It then shortens the body and pulls the rear end forward. In this way by repeating such muscular expansions and contractions earthworm moves.

7. How does the snail move?
Ans: The rounded structure on the back of the snail is called shell. It is the outer skeleton (exoskeleton) of snail. When it starts moving a thick structure and the head of the snail may come out of an opening in the shell. The thick structure is called foot, which is made up of strong muscles. It helps snail in moving.

8. How does fish move in water?
Ans: The body of fish is streamlined. The streamlined shape helps the fish to move in water. The skeleton of fish is covered with muscles which make the front part of the body to curve to one side and the tail part swings towards the opposite side. This makes a jerk and pushes the body forward. In this way it moves in water.

Class 6 Science Chapter 8 LONG ANSWER TYPE QUESTIONS

1. Explain various kinds of joints found in our body and give example of each.
Ans: There are five types of joints in our body:
(i) Fixed joints: Those joints which do not allow movement are called fixed joint.

(ii) Ball and socket joint: This joint allows movement in all directions. The rounded end of one bone fits into the hollow space of other bone. For example, joint between upper arm and shoulder.

(iii) Pivotal joint: This type of joint allow movement in all planes, i.e. up and down, side and other planes. For example, head.
(iv) Hinge joint: The joint which allows movement only in one plane is called hinge joint. For example, fingers, knees.

(v) Gliding joint: These joints allow only a limited amount of movement of sliding nature of cartilage. For example, the joints of backbone.

Class 6 Science Chapter 7 Textbook Questions Solved

1. Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of sepals and petals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together,
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
Ans:
(a) Roots absorb water and minerals from the soil.
(b) Roots hold the plant upright.
(c) Stem conducts water to the leaves.
(d) The number of petals and sepals in a flower is usually equal.
(e) If the sepals of a flower are joined together, its petals are not necessarily joined together.
(f) If the petals of a flower are joined together, then the pistil is not necessarily joined to the petal.

 2. Draw (a) a leaf, (b) a tap root and (c) a flower, you have studied for Table 7.3 of the textbook.
Ans:

3. Can you find a plant in your house or in your neighbourhood which has a long but a weak stem? Write its name. In which category would you classify it?
Ans: Yes, we find a money plant in our house. It is a climber.

4. What is the function of a stem in a plant?
Ans: A stem performs following functions:
(i) The stem and its branches hold leaves to get maximum sunlight.
(ii) It transports water from roots to different parts of the plant.
(iii) It transports food from leaves to different parts of the plant.
(iv) It bears leaves, flowers and fruits.

5. Which of the following leaves have reticulate venation?
Wheat, tulsi, maize, grass, coriander (dhania), china rose.
Ans: Tulsi, china rose.

6. If a plant has fibrous root, what type of venation are its leaves likely to have?
Ans: Parallel venation.

7. If a plant has leaves with reticulate venation, what kind of roots will it have?
Ans:Tap root.

8. Is it possible for you to recognise the leaves without seeing them? How?
Ans: We cannot exactly recognise the leaves without seeing them. We may be able to have some idea by touching and smelling them.

9. Write the names of the parts of a flower in sequence, from outside to inside.
Ans: The names of various parts of a flower from outside to inside are:
(i) Sepals
(ii) Petals
(iii) Stamens
(iv) Pistil

10. Which of the following plants have you seen? Of those that you have seen, which one have flowers?
Grass, maize, wheat, chilli, tomato, tulsi, pipal, shisham, banyan, mango, jamun, guava, pomegranate, papaya, banana, lemon, sugarcane, potato, groundnut
Ans:

11. Name the part of the plant which produces its food. Name this process.
Ans: Leaves produce food for the plant. This process is called photosynthesis.

12. In which part of a flower you are likely to find the ovary?
Ans: We find ovary in pistil. It is the lowermost part of the pistil.

13. Name two flowers, each with joined and separates sepals. 
Ans:
Flowers with joined sepals:
(i) Datura
(ii) Loki
Flowers with separate sepals:
(i) Gurhal
(ii) Mustard

EXTRA QUESTIONS for Class 6 Science Chapter 7 

Class 6 Science Chapter 7 VERY SHORT ANSWER TYPE QUESTIONS

1. List few plants found around your house.
Ans:  Mango, neem, grass, chilli, palak and banyan tree.

2. Are all the plants same in size?
Ans: No, all plants are of different sizes.

3. What are the major parts of plants?
Ans: Stem, root, leaves and flowers.

4. How many kinds of plants are there?
Ans: There are three kinds of plants:
(i) Herbs
(ii) Shrubs
(iii) Trees

5. Name two plants that belong to herbs.
Ans:
(i) Tomato
(ii) Potato

6. Give two examples of shrubs.
Ans:
(i) Lemon
(ii) Orange

7. Give two examples of trees.
Ans:
(i) Mango
(ii) Neem

8. Define petiole.
Ans: The part (stalk) of a leaf by which it is attached to the stem is called petiole.

9. What is lamina?
Ans:  The broad green flat part of leaf is called lamina.

10. What are veins?
Ans:  The lines on the leaf are called veins.

11. What is midrib?
Ans: A thick vein in the middle of the leaf is called midrib.

12. What is leaf venation?
Ans: The design made by veins in a leaf is called leaf venation.

13. How many types of leaf venation are there?

Ans: There are two types of leaf venation:
(i)  Reticulate venation
(ii)   Parallel venation

14. What is transpiration?
Ans: The process by which water comes out from the leaves in the form of vapour is called transpiration.

15. Name the process by which leaves can prepare their food.
Ans: This process is called photosynthesis.

16. What are the raw materials for photosynthesis?
Ans:
(i)    Sunlight
(ii)  Water
(iii) Carbon dioxide
(iv)   Chlorophyll

17. Where does the photosynthesis take place in plants?
Ans: It takes place in the leaves.

18.  Name the part of plant which helps in holding the plant in the soil.
Ans: Roots.

19. Name the types of roots shown in the Fig. 7.7.

Ans: (i) Tap roots (ii) Fibrous roots

20. What are tap roots?
Ans: The roots in which one root is main root and other lateral roots grow on it are called tap roots.

21. Give names of two plants which have tap root.
Ans: Gram and mustard.

Q. 22. Name two plants which have fibrous root.
Ans: (i) Wheat plant         (ii) Maize plant

23. What are lateral roots?
Ans: The smaller roots that grow on the main tap root are called lateral roots.

24. What are fibrous roots?
Ans: The roots which do not have any main root but all the roots are similar are called fibrous root.

25. Does the stem prepare food for any plant?
Ans: Yes, there are some plants whose stem prepares food, e.g. cactus.

26. Name the prominent parts of a flower.
Ans: The prominent parts of a flower are petals, sepals, stamens and pistil.

27. What are sepals? What are their functions?
Ans: The small green coloured leaf-life structures are called sepals. It protects flower when it is in stage of bud.

28. What are petals? Why are they generally coloured?
Ans: The coloured big leaf-life structures present in flower are called petals. Petals are coloured so as to attract insects for pollination.

29. What are stamens?
Ans:When we remove sepals and petals from the flower then we see some filaments in the flower which are called stamens. These, are the male part of the flower.

30. Name various parts of stamen.
Ans: There are two parts of a stamen:
(i) Anther (ii) Filament.
These are the male part of the flowers.

31. What is pistil?
Ans: The innermost part of a flower is called pistil. These are the female part of the flowers.

32. Name the various parts of pistil.
Ans: There are three parts of pistil:
(i) Stigma              (ii) Style             (iii) Ovary

33. What are ovules?
Ans: These are small bead-like structures inside the ovaiy.

Class 6 Science Chapter 7 SHORT ANSWER TYPE QUESTIONS
1. What are weeds?
Ans: The unwanted plants that grow in the fields with the main crops or in their surroundings are called weeds. Weeds are the plants which are not grown by the farmers. For example, grass.

2. Classify plants and give an example of each.
Ans: On the basis of various characteristics most of the plants can be classified into three categories:
(i) Herbs, e.g. tomato
(ii) Shrubs, e.g. lemon
(iii) Trees, e.g. mango

3. What are herbs? Give two examples.
Ans: The plants with green and tender stems are called herbs. They are usually short and may have no or less branches. For example, tomato, potato.

4. What are shrubs? Give two examples.
Ans: The plants which have a hard but not a very thick stem are called shrubs. Such plants have the stem branching out near the base. For example, lemon, rose plants.

5. What are trees? Give two examples.
Ans: The plants which are very tall and have hard and thick brown stem are called trees. The stems have branches in upper part and much above the ground. For example, mango, neem.

6. What are creepers? Write an example.
Ans. The plants with weak stem that cannot stand upright and spread on the ground are called creepers. Various types of grasses are the examples of creepers.

7. What are climbers?
Ans: The plants that take support of neighbouring structures and climb up are called climbers. They have weak stem. For example, grapes, money plant, beans.

8. Explain an activity to show that stem conducts water and other substances.
Ans: Take some water in a glass. Add few drops of red ink to the water. Cut the stem of a herb plant from its base. Put it in the glass as shown in figure. We will see that some parts of the stem become red. This activity shows that stem conducts water.

9. Explain the structure of a leaf with the help of a labelled diagram.
Ans: There are two main parts of leaf:
(i) Petiole: The part of the leaf by which it is attached to the stem is called petiole.
(ii) Lamina: The broad, green part of the leaf is called lamina.

The lamina contains following parts:
(i) Veins: There are various types of lines on the leaf. These lines are called veins
(ii) Midrib: There is a thick vein in the middle of the leaf. This vein is called midrib.

10. Explain the main functions of leaf.
Ans: There are following two main functions of leaf:
(i) Transpiration: The extra water comes out of the leaves in the form of vapour. This process is called transpiration.
(ii) Photosynthesis: The process by which leaves prepare their food from water and carbon dioxide, in the presence of sunlight and a green-coloured substance, is called photosynthesis.

11. What are unisexual and bisexual flowers?
Ans: Unisexual flower has either male (stamen) or female (pistil) parts.
Bisexual flowers have both male and female whorl in the flowers, i.e., they have both stamen and pistil.

12. Name a plant that eats insect.
Ans: Pitcher plant.

13. Pitcher plant has green leaves which can prepare food by photosynthesis then why does it eat insects?
Ans: To get nitrogenous compounds which it cannot absorb from the soil.

14. Name a plant that has underground as well as aerial (above the ground) root system.
Ans: Banyan tree.

15. Why do we see dew drops on leaves in the early morning?
Ans: At night the water lost by leaves does not get evaporated and gets collected on the leaves in the form of dew drops.

16. Why are petals colourful?
Ans: The colourful petals attract insects for pollination.

17. Why does white flowers bloom at night?
Ans: White colour attracts night insects for pollination.

18. What do you mean by a complete and incomplete flower?
Ans: The flower with all whorls, i.e., sepals, petals, stamen and carpel in it is a complete flower. If any one of this is absent in a flower it is called an incomplete flower.

19. Leaves need oxygen and carbon-dioxide (for photosynthesis). How do they get these gases?
Ans: Leaves take in these gases from atmosphere through small pores present on them called stomata.

20. How can one destarch the leaves of potted plant without plucking, them?
Ans: By keeping it in dark for 2-3 days.

21. What is the relation between leaf venation and the type of roots?
Ans: The plants having tap root have reticulate venation. The plants having fibrous roots have parallel venation.

22. Name the male part of a flower. Write names of its parts and draw a diagram.
Ans: The male part of a flower is called stamen. It has two parts: (i) Filament and (ii) Anther.

23.Name the female part of a flower. Write names of its parts and draw a diagram.
Ans:The female part of a flower is called pistil. It has three parts: (i) Stigma, (ii) Style, and (iii) Ovary.

24. Differentiate between tap root and fibrous root.
Ans:

Class 6 Science Chapter 7 LONG ANSWER TYPE QUESTIONS

1. What do you mean by leaf venation? Explain various types of leaf venation with example.
Ans: Leaf venation: The design made by veins in a leaf is called leaf venation. There are the following two types of leaf venation:
(i) Reticulate venation: If the design of veins makes a net-like structure on both the sides of midrib then it is called reticulate venation. For example, mango leaf, gram leaf.
(ii) Parallel venation: If the veins are parallel to each other or to midrib then such type of venation is called parallel venation. For example, wheat leaf, barley leaf.

2. Explain the structure of a typical flower with the help of a diagram.
Ans: A typical flower contains the following parts:
(i) Stalk: The part by which a flower is attached to the branch is called stalk.
(ii) Sepals: The small green leaf-like structures of the flower are called sepals,
(iii) Petals: The big coloured leaf-like structures are called petals. Different flowers have petals of different colours.
(iv) Stamen: It is the male part of the flower. It has two parts: (a) Filament and (b) Anther.
(v) Pistil: The innermost part of a flower is called pistil. It has three parts: (a) Stigma, (b) Style and (c) Ovary. It is the female part of the flower.

3. Explain an activity to test the presence of starch in a leaf.
Ans: Take a leaf in a test tube and pour spirit till it completely covers the leaf. Now put the test tube in a beaker having water. Heat the beaker till all the green colour from the leaf comes out into the spirit in the test tube. Take out the leaf and wash it with water. Put it on a plate and pour some iodine solution over it. The iodine solution is brown in colour but when it comes in contact with starch it turns blue-black. The iodine solution will turn blue-black when dropped on the leaf, this confirms the presence of starch in the leaf.

4. Explain that sunlight is essential for photosynthesis.
Ans: Take a potted plant having green leaves. Place it in a dark room for a day or two so that all the starch present in leaves is used by the plant. Now cover a portion of leaf with black paper and keep the plant in the sun for a day. Pluck the leaf, remove the black paper and test it for the starch. We see that only that part of the leaf becomes blue-black which was open to sun. The covered part does not become blue-black. This shows that no starch is formed because it gets no sunlight.

5. Explain the important functions of root.
Ans:. The following are the functions of root:
(i) They help to absorb water from the soil.
(ii) The roots help in holding the plants firmly in the soil.
(iii) They are said to anchor the plant to the soil.

6. Explain various kinds of roots with the help of an example.
Ans: There are following two types of roots:
(i) Tap roots: The roots which have one main root and other smaller lateral roots are called tap roots. For example, mustard plant, gram.
(ii) Fibrous roots: The roots which have no main root but all the roots appear similar are called fibrous roots. For example, maize, wheat.

1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Ans: Yes, it can be reversed by unfolding the dress.

2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?
Ans: No, this change (breaking of toy) cannot be reversed.

3. Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.

4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?
Ans: No, we cannot get fresh drawing sheet once a picture is drawn on it with paint/ oil or water. However, we can reverse the change, if soft pencil is used to draw the picture.

5. Give examples to explain the difference between changes that can or cannot be reversed.
Ans: Examples of reversible and irreversible changes

6. A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Ans: No, the change in POP cannot be reversed since it is a chemical change.

7. A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?
Ans. No, these are irreversible chemical changes.

EXTRA QUESTIONS for Class 6 Science Chapter 6

Class 6 Science Chapter 6 VERY SHORT ANSWER TYPE QUESTIONS

1. Give two examples of slow changes.
Ans:
(a) Growing of plants
(b) Ripening of fruits.

2. Give two examples of fast changes.
Ans:
(a) Blowing of balloon
(b) Rolling out roti from dough ball.

3. Give two examples of reversible changes.
Ans:
(a) Drying of wet clothes
(b) Heating of milk.

4: Give two examples of irreversible changes.
Ans:
(a) Milk to cheese
(b) Cooking of food.

5. Can you say deforestation is an irreversible or reversible change?
Ans: It is an irreversible change.

6. Does the size of the paper change after making an aeroplane by folding it or by cutting it?
Ans: Yes.

7. Can you change the shape of a eraser after erasing?
Ans: Yes.

8. Why does a blacksmith heat the metal rim to fix it on a cart wheel?
Ans: A blacksmith heats the metal rim to fix it onto a cart wheel because a metal rim is made slightly smaller. On heating, the rim expands and fits onto the wheel. Then on cooling, the rim contracts and fits tightly onto the wheel.

9. What are slow and fast changes? Give examples.
Ans: The changes which take place in a long period of time are called slow changes whereas that changes which take place in a short period of time are called fast changes.
Examples:
(a) Rusting of iron, formation of day and night, ripening of fruits, growing of trees are slow changes.
(b) Burning of paper, stretching of rubber band, blowing of balloons, bursting of crackers are fast changes.

10. Classify the following into slow and fast changes:
(i) Spinning of top
(ii) Formation of day and night
(iii) Formation of curd from milk
(iv) Change of season
(v) Making curd from milk by adding lemon juice.
Ans:
(i) Fast change
(ii) Slow change
(iii) Slow change
(iv) Slow change
(v) Fast change.

11. Classify the following as slow or fast change:
(i) Bearing of heart
(ii) Change of seasons
(iii) Burning of paper
(iv) Weathering of rocks
(v) Melting of wax
(vi) Cooking of food
(vii) Burning of wax
(viii) Melting of ice cream
(ix) Curding of milk
(x) Formation of day and night
Ans:
(i) Fast
(ii) Slow
(iii) Fast
(iv) Slow
(v) Fast
(vi) Slow
(vii) Fast
(viii) Fast
(ix) Slow
(x) Slow

12. Write some changes happening in our body.
Ans:
(a) Our nails grow
(b) Our hair grows
(c) We grow taller
(d) Our weight increases.

 13. Some common changes are given in Table 6.1. Which of these changes do you think can be reversed?

Class 6 Science Chapter 6 SHORT ANSWER TYPE QUESTIONS

1. What is a physical change? Explain with example.
Ans: The changes in which only physical properties of substances are changed and no new substance is formed is called physical change. It is a reversible change. Example: Boiling and freezing of water.

2. What is a chemical change? Explain with example.
Ans: The changes in which new substance with new chemical properties are formed are called chemical changes.
Example: Reaction between washing soda and lemon juice in which C0₂ and other substances are formed.

3. What happens when sugar is heated?
Ans: When sugar is heated continuously then a black powdery substance is formed. This is a chemical change.

Class 6 Science Chapter 6 LONG ANSWER TYPE QUESTIONS

1. Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.
Ans: The metal rim is always made slightly smaller than the wooden wheel. The metal rim is heated. On heating, the rim expands and fit onto the wheel. Cold water is then poured over the rim. Due to cooling the metal rim contracts and fits tightly onto the wheel.

2. How does curd being set? Is this change reversible?
Ans: A small quantity of curd is added to warm milk. The milk is stirred and is set aside undisturbed for a few hours at a warm place. In a few hours, the milk changes into curd.
Curd formed from milk cannot be changed into milk again. So, this an irreversible (cannot be reversed) change.

1. Why do we need to separate different components of a mixture? Give two examples.
Ans: Among different components of mixture there are many substances which are harmful or not useful for us. To remove these harmful or unuseful components we need to separate them. For example:
(a) Tea leaves are separated from the liquid with a strainer while preparing tea.
(b) Stone pieces from wheat, rice or pulses are picked out by hand.

2. What is winnowing? Where is it used?
Ans: Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. This process is used by farmers to separate lighter husk particles from heavier seeds of grain.

3. How will you separate husk or dirt particles from a given sample of pulses before cooking?
Ans: Husk or dirt particles can be separated by winnowing, being lighter they wall fly away from pulses.

4. What is Sieving? Where can it be used?
Ans. Sieving is a process by which fine particles are separated from bigger particles by using a sieve. It is used in flour mill or at construction sites. In flour mill, impurities like husks and stones are removed from wheat. Pebbles and stones are removed from sand by sieving.

5. How will you separate sand and water from their mixture?
Ans. We will separate sand and water by sedimentation and decantation method. First we leave this mixture for some time. After some time, the sand which is; heavier is settled down at the bottom. After that we wall pour water into another container and the mixture will be separated.

 6. Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?
Ans. Sugar can be separated from wheat flour by sieving. Due to difference in the size of particles, sugar will stay on sieve and wheat flour will pass through it.

7. How would you obtain clear water from a sample of muddy water?
Ans. We will obtain clear water from a sample of muddy water by the process of filtration.
A filter paper is one such filter that has very fine pores in it. Figure 5.12(a, b) shows the steps involved in using a filter paper. A filter paper folded in the form of a cone is fixed in a funnel. The mixture is then poured on the filter paper. Solid particles in the mixture do not pass through it and remain on the filter.

8. Fill in the blanks:
(a) The method of separating seeds of paddy from its stalks is called .
(b) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of ______. 
(a) Salt is obtained from sea water by the process of ____________ .
(b) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off from the top. The process of separation used in this example is called ____________.
Ans.
(a) threshing
(b)filtration
(b) evaporation
(d) sedimentation and decantation

9. True or false?
(a) A mixture of milk and water can be separated by filtration.
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.
(c) Separation of sugar from tea can be done with filtration.
(d) Grain and husk can be separated with the process of decantation.
Ans.
(a) False
(b) False
(c) False
(d) False

10. Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar ? In which case would it be possible to dissolve more sugar ?
Ans. We should add ice after dissolving sugar. When the temperature is high then more sugar can be dissolved. After mixing ice it gets cool and less sugar will dissolve in it.

EXTRA QUESTIONS for Class 6 Science Chapter 5

Class 6 Science Chapter 5 VERY SHORT ANSWER TYPE QUESTIONS

1. What is strainer?
Ans. Strainer is a kind of sieve which is used to separate a liquid from solid.

2. Name the method used to separate cream from curd.
Ans. Centrifugation.

3. How will you separate mango from a mixture of mango and apple?
Ans. By picking.

4. You are given a mixture of salt and sand. Can you separate them by picking?
Ans. No, we cannot separate them by picking.

5. Name the method used to separate the pieces of stone from grain.
Ans. Handpicking.

6. How can you separate grains from stalk?
Ans. We separate grains from stalk by threshing.

7. What types of material can we separate by using handpicking?
Ans. The materials having different size and colour can be separated by handpicking.

8. Name the other methods used to separate solid materials of different size.
Ans. Sieving.

9. Name the process used to separate heavier and lighter components of a mixture.
Ans. Winnowing.

10. Can the above stated method be used if both the components have same weight?
Ans. No, this method cannot be used.

11. What is evaporation?
Ans. The process of conversion of water into vapour is called evaporation.

12. Name the method by which we get salt from ocean water.
Ans. Evaporation.

13. Define condensation.
Ans. The process of conversion of water vapour into liquid form is called condensation.

14. Write opposite process of evaporation.
Ans. Condensation.

Class 6 Science Chapter 5 SHORT ANSWER TYPE QUESTIONS

l. What is mixture?
Ans. When two or more than two substances are mixed together in any ratio then it is called a mixture.

2. Write various methods of separation of components from their mixture.
Ans.

1. Handpicking
2. Threshing
3. Winnowing
4. Sedimentation
5. Decantation
6. Filtration
7. Evaporation
8. Condensation

3. Define the term handpicking.
Ans. The process used to separate slightly larger particles from a mixture by hand is called handpicking. For example: Stone pieces can be separated from wheat or rice by handpicking.

4. What do you mean by threshing? Where is it used?
Ans. Threshing is a process in which we separate grain from stalks. This process is used by farmer to separate gram, wheat, rice, mustard seeds in his field.

5. Write three methods of separation.
Ans. Handpicking, threshing and winnowing.

6. How will you separate oil and water from their mixture?
Ans. Oil, being lighter than water, will float on it. Two distinct layers are formed and slowly oil is allowed to flow into another container and is separated from water. Separating funnel can also be used to separate the two.

 7. What is evaporation?
Ans. The process of conversion of water into vapour is called evaporation. This process takes place continuously where water is present. Common salt from sea water is obtained using this method.

8. Define winnowing.
Ans. The process is used to separate components from a mixture in which one component is heavier or lighter than other is called winnowing. Winnowing is done with the help of wind or by blowing air.

 9. What do you mean by sieving? Give an example.
Ans. Sieving allows the fine flour particles to pass through the holes of the sieve while the bigger particles or impurities remain on the sieve. For example, in a flour mill, impurities like husk and stones are removed from wheat before grinding it.

10. Match the column:

Class 6 Science Chapter 5 LONG ANSWER TYPE QUESTIONS

1. What is threshing?
Ans. Threshing is a process that is used to separate grain from stalks. In this process the stalks are beaten to free the grain seeds. Sometimes threshing is done with the help of bullocks. Machines are also used to thresh large quantities of grain.

2. Describe the method to obtain salt from sea water.
Ans. Sea water contains many salts mixed in it. One of them is common salt, when sea water is allowed to stand in shallow pits, water gets evaporated by sunlight and slowly turns into water vapour. In a few days, the water evaporates completely leaving behind the solid salts. Common salt is then obtained from this mixture of salts by further purification.

3. What is decantation?
Ans. Decantation is a process, of separation of insoluble solids from liquid. The suspension of solid particles in liquid is allowed to stand for some time. The solid particles then settle down at the bottom of the container and clean water goes up. Without disturbing the settled particles the clean water is transferred into other container.

 4. Where is decantation used? Give two examples.
Ans.
(i) Decantation is used to separate insoluble solids or liquid from liquid. Rain water is a mixture of mud and water. It is purified by decantation.
(ii) Oil and water also get separated by this method because oil floats up.

 5. How will you prepare cheese (paneer)?  
Ans. For making paneer, a few drops of lemon juice sire added to milk as it boils. This gives a mixture of particles of solid paneer and liquid. The paneer is then separated by filtering the mixture through a fine cloth or strainer.

6. Explain the method that can be used for separating the following mixture:
(i) Sand and husk
(ii) Wheat, sugar and stalk
(iii) Water and petrol
(iv) Rice and salt
(v) Sand and salt
Ans.
(i) Mixture of sand and husk: Sand and husk can be separated by the method of winnowing.
(ii) Mixture of wheat, sugar and stalk: For separating stalk from the mixture we should follow the winnowing method because milk is lighter than other two components and get separated. Wheat and sugar can be separated by sieving because they are in different sizes.
(iii) Mixture of water and petrol: Water does not dissolve in petrol. So, it can be separated by the use of separating funnel.
(iv) Mixture of rice and salt: Rice and salt can be separated by sieving.
(v) Mixture of sand and salt: Sand and salt is mixed with water, salt dissolves in water and sand can be separated solution by sedimentation and decantation followed by filtration. After that using evaporation common salt is separated.