CLASS-6 SCIENCE SOLUTION
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CHAPTER-6
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CHANGES AROUND US
Exercise Questions
1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Solution:
Yes, the process can be reversed.
2. You accidentally dropped your favorite toy and broke it. This is a change you did not want. Can this change be reversed?
Solution:
No, this change 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.
Sl No Change Can be reversed Yes/No
1 The sawing of a piece of wood
2 The melting of ice candy
3 Dissolving sugar in water
4 The cooking of food
5 The ripening of a mango
6 Souring of milk
Solution :
Sl No Change Can be reversed Yes/No
1 The sawing of a piece of wood No
2 The melting of ice candy Yes
3 Dissolving sugar in water Yes
4 The cooking of food No
5 The ripening of a mango No
6 Souring of milk No
4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?
Solution:
This change can be reversed if a pencil is used to draw the picture. If a pen, paint, oil /water colours are used to draw the picture, change cannot be reversed.
5. Give examples to explain the difference between changes that can or cannot be reversed.
Solution:
Changes that can be reversed
i) Opening and closing the door
ii) Filling glass with water
Changes that cannot be reversed
i) Conversion of milk into curd
ii) Ripening of fruit
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 immobilized. Can the change in POP be reversed?
Solution:
No, the change cannot be reversed
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?
Solution: No, the change cannot be reversed
CLASS-6 SCIENCE SOLUTION
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CHAPTER-5
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SEPARATION INTO SUBSTANCES
Exercise Questions
1. Why do we need to separate different components of a mixture? Give two examples.
Solution:
When two or more substances are mixed together they form a mixture. Components of a mixture should be separated because some components may not be useful or may spoil the useful component of the mixture.
Examples:
Tea leaves are separated from the liquid with a strainer, while preparing tea
Removal of stone pieces from wheat, rice or pulses by hand
2. What is winnowing? Where is it used?
Solution:
The method of separating the components from a mixture is known as winnowing. In this method, heavier and lighter components of a mixture are separated by wind or by blowing air. This method 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?
Solution:
Husk and dirt particles are separated from pulses by winnowing.
4. What is sieving? Where is it used?
Solution:
Sieving is a method in which fine particles are sieved through holes of the sieve while the bigger impurities remain on the sieve. Sieving is used in a flour mill to separate impurities like husk and stones from wheat before grinding it. It is also used at construction sites to separate pebbles and stones from sand.
5. How will you separate sand and water from their mixture?
Solution:
Sand and water are separated from their mixture by the following steps:
a) The mixture is allowed to stand without any disturbances
b) Now sand settles down
c) Slowly pour the water into another container to obtain sand in the bottom
6. Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?
Solution:
Yes it is possible to separate sugar mixed with wheat flour by the following method
a) Mix sugar and wheat flour in water
b) Stir the solution to allow sugar to dissolve
c) Now filter the mixture
d) Filtrate contains sugar solution and residue will be wheat flour.
7. How would you obtain clear water from a sample of muddy water?
Solution:
The following process should be carried out to obtain clear water from muddy water
i) Allow muddy water to stand
ii) Mud gets settled down in the water
ii) Slowly pour water to another container
8. Fill up 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 ___________.
(c) Salt is obtained from seawater by the process of ___________.
(d) 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 ___________.
Solution:
(a) The method of separating seeds of paddy from its stalks is called threshing.
(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 filtration.
(c) Salt is obtained from seawater by the process of evaporation.
(d) 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 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.
Solution:
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?
Solution:
Ice should be added to lemonade after dissolving sugar. It is possible to add more sugar before adding ice.
CLASS-6 SCIENCE SOLUTION
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CHAPTER-4
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SORTING MATERIALS INTO GROUP
Exercise Questions
1. Name five objects which can be made from wood.
Solution:
a) Table
b) Chair
c) Doors
d) Desk
e) Box
2. Select those objects from the following which shine: Glass bowl, plastic toy, steel spoon, cotton shirt
Solution:
Glass bowl and steel spoon are the objects which shine
3. Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a given material could be used for making many objects.
Objects Material
Book Glass
Tumbler wood
Chair Paper
Toy Leather
Shoes Plastics
Solution:
Objects Material
Book Paper, Wood
Tumbler Glass, wood, plastic
Chair wood, plastic
Toy Glass, Wood, Paper, Plastics, Leather
Shoes Leather, Plastic
4. State whether the statements given below are True or False.
(i) Stone is transparent, while glass is opaque.
(ii) A notebook has lustre while eraser does not.
(iii) Chalk dissolves in water.
(iv) A piece of wood floats on water.
(v) Sugar does not dissolve in water.
(vi) Oil mixes with water.
(vii) Sand settles down in water.
(viii) Vinegar dissolves in water.
Solution:
i) False
ii)False
iii) False
iv) True
v) False
vi) False
vii) True
viii) True
5. Given below are the names of some objects and materials:
Water, basket ball, orange, sugar, globe, apple and earthen pitcher. Group them as:
(a) Round shaped and other shapes (b) Eatables and non eatables
Solution:
(a) Round shaped – Basketball, Orange, Globe, Apple, Earthen pitcher
Other shapes – Water, Sugar
(b) Eatables – Water, Orange, Sugar, Apple
Non eatables – Basketball, Globe, Earthen pitcher
6. List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Solution:
Few items that float on water are as follows:
Sponge’s piece
Plastic bottle
Paper’s piece
Thermocol’s piece
Wood
Plastic ball
Cork
However, these items will not float on an oil or kerosene
7. Find the odd one out from the following:
a) Chair, Bed, Table, Baby, Cupboard
b) Rose, Jasmine, Boat, Marigold, Lotus
c) Aluminum, Iron, Copper, Silver, Sand
d) Sugar, Salt, Sand, Copper sulphate
Solution:
a) Baby – others are made up of wood
b) Boat – others are flowers
c) Sand – others are metals
d) Sand – others are soluble in water
CLASS-6 SCIENCE SOLUTION
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CHAPTER-3
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FIBRE TO FABRIC
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Exercise Questions
1. Classify the following fibers as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute
Solution:
Natural: Wool, Cotton, Silk, Jute
Synthetic: Nylon, Polyester
2. State whether the following statements are true or false:
a) Yarn is made from fibres.
b) Spinning is a process of making fibres.
c) Jute is the outer covering of coconut.
d) The process of removing seed from cotton is called ginning.
e) The weaving of yarn makes a piece of fabric.
f) The silk fibre is obtained from the stem of a plant.
g) Polyester is a natural fibre.
Solution:
a) True
b) False
c) False
d) True
e) True
f) False
g) False
3. Fill in the blanks:
a) Plant fibres are obtained from_________ and ________ .
b) Animals fibres are __________ and ___________ .
Solution:
a) Plant fibres are obtained from cotton and jute.
b) Animals fibres are silk and wool.
4. From which parts of the plant cotton and jute are obtained?
Solution:
Cotton is obtained from the fruits of the cotton plant and Jute is obtained from the stem of the jute plant.
5. Name two items that are made from coconut fiber.
Solution:
Gunny bags, Ropes and Mats.
6. Explain the process of making yarn from fiber.
Solution:
Yarn can be made from fibre by the process called Spinning. From the mass of cotton, fibres are drawn and twisted which brings together the fibres to form a yarn. Takli and Charkha are the devices used for spinning.
