Solutions to NCERT Class 6 Science Curiosity Chapter 9 Methods of Separation in Everyday Life

Hello students and welcome to Chapter 9! Our experts have thoroughly answered all ‘Let us enhance us your learning’ in this material. If you need even more practice – look at the solutions to the self-designed extra questions that we have included as well. In all, this material answers all your questions on this topic and will prepare you for your exams.

Solutions to ‘Let us enhance our learning’ (Page No 178) of NCERT Class 6 Science Curiosity Chapter 9 Methods of Separation in Everyday Life

1. What purpose does handpicking serve in the process of separation?

(i) Filtration               (ii) Sorting

(iii) Evaporation       (iv) Decantation

Solution:

(ii) Sorting

Handpicking is used to sort a small number of large impurities from a mixture.

2. Which of the following substances are commonly separated using the churning method?

(i) Oil from water                   (ii) Sand from water

(iii) Cream from milk          (iv) Oxygen from air

Solution:

(iii) Cream from milk

During churning, the cream being lighter floats on the top of the milk and can be separated from the milk.

3. Which factor is usually essential for the filtration?

(i) Apparatus size              (ii) Presence of air

(iii) Pore size                      (iv) Presence of air Temperature of the mixture

Solution:

(iii) Pore size

Very fine pore size is essential for filtration so that even small impurities are left behind on the filter paper.

4. State with reason(s) whether the following statements are True [T] or False [F]. Also, correct the False statement(s).

(i) Salt can be separated from salt solution by keeping it under the Sun. [  ]

(ii) Handpicking should be used only when the quantity of one component is less. [  ]

(iii) A mixture of puffed rice and rice grains can be separated by threshing. [  ]

(iv) A mixture of mustard oil and lemon water can be separated by decantation. [  ]

(v) Sieving is used to separate a mixture of rice flour and water. [  ]

Solution:

(i) Salt can be separated from salt solution by keeping it under the Sun. [  ]

True [T]. Explanation: When the salt solution is kept under the sun, the water will evaporate due to the heat and salt will be left behind.

(ii) Handpicking should be used only when the quantity of one component is less. [  ]

True [T]. When the quantity of one component is less, the process of handpicking is convenient.

(iii) A mixture of puffed rice and rice grains can be separated by threshing. [  ]

False [F]. Correct Statement: A mixture of puffed rice and rice grains can be separated by winnowing.

Explanation: Puffed rice is lighter than rice grains and is carried further away by the wind, thus causing separation.

(iv) A mixture of mustard oil and lemon water can be separated by decantation. [  ]

True [T].

Explanation: The mustard oil floats on top of lemon water and hence can be separated by decantation.

(v) Sieving is used to separate a mixture of rice flour and water. [  ]

False [F]. Correct Statement: Sieving is used to separate a mixture of solids of different sizes and not a mixture of solid and liquid.

5. Match the mixtures in Column I with their method of separation in Column II.

Column I	Column II
(i) Gram flour mixed with black gram	(a) Handpicking
(ii) Chalk powder mixed with water	(b) Magnetic separation
(iii) Corn mixed with potatoes	(c) Decantation
(iv) Iron powder mixed with sawdust	(d) Sieving
(v) Oil mixed with water	(e) Filtration

Solution:

Column I	Column II
(i) Gram flour mixed with black gram	(d) Sieving
(ii) Chalk powder mixed with water	(e) Filtration
(iii) Corn mixed with potatoes	(a) Handpicking
(iv) Iron powder mixed with sawdust	(b) Magnetic separation
(v) Oil mixed with water	(c) Decantation

6. In what situations would you use decantation instead of filtration to separate solids from liquids?

Solution:

You would use decantation instead of filtration to separate solids from liquids when the solid particles are heavy enough to settle at the bottom of the beaker, allowing the clear liquid to be poured off. Examples, stone chips mixed with water.

7. Can you relate the presence of nasal hair to any separation process?

Solution:

Yes, the presence of nasal hair causes separation of solid dust particles from the air we breathe. This is similar to the process of separation by filtration.

8. During the COVID-19 pandemic, all of us wore masks. Generally, what material are they made of? What is the role of these masks?

Solution:

During the COVID-19 pandemic, masks were generally made of materials such as cotton, and plastics like polyester and polypropylene, or a combination of these. The role of these masks was to prevent inhaling virus-containing particles and also to trap droplets from the wearer’s mouth and nose, reducing the spread of the virus to others.

9. A mixture containing potatoes, salt and sawdust has been given to you. Outline a stepwise procedure for separating each component from this mixture.

Solution:

The stepwise procedure for separating each component from the given mixture is given below:

Step 1 (Handpicking): The large-sizes potatoes are easily handpicked from the mixture.

Step 2: Add water to the remaining mixture of salt and sawdust. The salt will dissolve in water.

Step 3 (Filtration): Filter the mixture using filtration apparatus. This separates the sawdust, which remains on the filter paper.

Step 4 (Evaporation): Evaporate the water from the remaining salt-water solution to obtain salt.

10. Read the following story titled ‘Intelligent Leela’ and tick the most appropriate options. Provide a suitable title of your choice for the paragraph.

Leela was working in the farm with her father when she realised that they left their drinking water at home. Before her father felt thirsty/hungry, she went to the nearby pond to fetch some water/grains. After obtaining some water in the container, she noticed that the water was muddy and fit/unfit for drinking. To purify the water, she kept it for some time and then she filtered/ churned the muddy water using a piece of paper/muslin cloth. Leela, then, cooled/boiled the water for about 10 minutes in a covered pan. After cooling/boiling, she filtered/churned it again and made it fit/unfit for drinking. She served this water to her father while having food, who blessed her and appreciated her efforts.

Solution:

Leela was working in the farm with her father when she realised that they left their drinking water at home. Before her father felt thirsty, she went to the nearby pond to fetch some water. After obtaining some water in the container, she noticed that the water was muddy and unfit for drinking. To purify the water, she kept it for some time and then she filtered the muddy water using a piece of muslin cloth. Leela, then, boiled the water for about 10 minutes in a covered pan. After cooling, she filtered it again and made it fit for drinking. She served this water to her father while having food, who blessed her and appreciated her efforts.

A suitable title of my choice for the paragraph would be: “Leela’s Mini Water Purification Plant”.

Solutions to In Text Questions of NCERT Class 6 Science Curiosity Chapter 9 Methods of Separation in Everyday Life

1. (Page 165) A small amount of puffed rice is mixed with chana dal. Can you think of separating the mixture by any method other than handpicking?

Solution:

Puffed rice can be separated from chana dal using the winnowing method. Since puffed rice is lighter than chana dal, the wind will carry the lighter puffed rice further away, while the heavier chana dal will fall straight down, effectively separating the two.

2. (Page 166) Valli is unable to separate husk from rice in a closed room. How can you help her?

Solution:

You can take a mixture of husk and rice on a bamboo tray and blow air over it using a fan, while Valli moves the tray in the direction of the wind. By this process of winnowing, the lighter husk will blow far away, leaving the heavier rice behind. Thus, husk can be separated from rice.

3. (Page 167) Have you ever observed sieves being used at construction sites to separate pebbles and stones from the sand?

Solution:

Yes, sieves are used at construction sites to separate pebbles and stones from the sand. The smaller sand particles pass through the holes, while the larger pebbles and stones are retained on top.

4. (Page 168) Have you ever observed white patches on the dark coloured clothes you wear during hot summers? How are these patches formed?

Solution:

White patches on dark-coloured clothes worn during hot summers are often formed due to salt and minerals excreted from the body along with sweat. As the sweat evaporates, the salt and mineral residues are left behind, which appear as white patches on the fabric.

5. (Page 171) How many layers of cloth do I need to use to get clear water?

Solution:

To get clear water, you should use 3 to 4 layers of cloth. Using multiple layers ensures better filtration by successively trapping finer impurities, resulting in clearer water.

6. (Page 174) Can you name one kitchen appliance which runs on electricity that is used to prepare buttermilk?

Solution:

A blender is a kitchen appliance that runs on electricity and is commonly used to prepare buttermilk. During the churning process, the butter rises to the top and is separated from the liquid i.e. buttermilk.

Extra Questions to Complement Solutions to NCERT Class 6 Science Curiosity Chapter 9 Methods of Separation in Everyday Life

Very Short Answer Type Questions:

1. How are tea leaves separated from the liquid?
Answer:
Tea leaves separated from the liquid with a strainer. The process is called filtration.

2. How is butter separated from milk or curd?
Answer:
Butter is separated from milk or curd by churning.

3. How do you separate mangoes from guavas?
Answer:
Mangoes are separated from guavas by handpicking.

4. What is the process of separating grains from stalks?
Answer:
The process of separating grains from stalks is called threshing.

5. What is a mixture?
Answer:
A mixture is a combination of two or more substances.

6. How is a solution prepared?
Answer:
Solution is prepared by dissolving a certain amount of substance in a liquid.

7. Name a place where you can perform separation experiments?
Answer:
You can perform separation experiments in a science laboratory.

8. What is the separating agent in winnowing?
Answer:
The substances are separated by wind or blowing air in winnowing.

9. Does one separation process work for separating mixtures?
Answer:
Sometimes multiple processes are needed for separating mixtures.

10. Is air a mixture?
Answer:
Air is a mixture of gases, namely nitrogen, carbon dioxide, oxygen etc.

Short Answer Type Questions:

1. Name the processes to separate solids from other solids.
Answer:
Handpicking, threshing, winnowing, sieving are processes to separate solids from other solids.

2. What is the process of separating oil from water?
Answer:
Oil is separated from water by the following process:

(i) The mixture of oil and water is allowed to stand for some time. Oil and water do not mix, so they form two separate layers.

(ii) Oil, being lighter, will form the top layer. It can be separated by decantation.

3. Can you separate a mixture of sugar dissolved in water using filtration?
Answer:
No. Sugar is dissolved in the water, so there are no solid particles to separate using filtration. The whole mixture will pass through the filter paper.

4. List the processes for separating solid from liquid.
Answer:
Sedimentation and decantation, filtration, churning, evaporation and condensation.

5. How can you dissolve more sugar in a saturated solution of sugar and water?
Answer:
To dissolve more sugar in a saturated solution of sugar and water:

(i) You can add more water to the mixture.

(ii) You can heat the solution up.

6. What is the criteria for making a good filter paper?
Answer:
A good filter paper should have very small pores in order to separate even the smallest impurities.

7. What factor decides which substance will settle in sedimentation?
Answer:
The weight of the substance. The heavier substance will sink and settle.

8. How is common salt separated from sea water?
Answer:
Salt is separated from sea water using the following steps:

(i) Sea water is allowed to stand in shallow pits.

(ii) Sea water gets heated by sunlight and slowly evaporates to become water vapour. The salt is left behind.

(iii) Common salt in then separated by further purification from the other salts.

9. How are impurities separated from flour?
Answer:
Impurities are separated from flour by the process of sieving. You pour the flour into the sieve. This results in the smaller flour particles to pass through the holes of the sieve while the bigger impurities remain on the sieve.

10. Can a soft drink be called a mixture?
Answer:
Yes, a soft drink can be called a mixture because it involves a gas and other substances dissolved in a liquid.

Long Answer Type Questions:

1. A mixture of iron nails, salt, oil and water is provided to you. Give stepwise methods to separate each component from this mixture?

Answer:

Here are the steps to follow:

(i) The iron nails can be separated using a magnet by the process of magnetic separation. We are now left with salt, oil and water.

(ii) The oil will rise to the top of the water and can be separated using decantation. Now, we are left with a solution of salt dissolved in water.

(iii) This solution can be put in a kettle and boiled. A cold pan with ice on the backside is held against the spout of the kettle and a beaker is kept below the pan. The water evaporates and then condenses on the cold surface of the pan. The droplets falling off the surface of the pan are then collected in the beaker. The salt is left behind in the kettle.

Thus, the mixture can be separated by successive methods of magnetic separation, decantation, evaporation and condensation.

Match and pair:

Column A	Column B
(i) Winnowing	(a) Bunsen burner
(ii) Stir the mixture	(b) Wind
(iii) Separate bran from flour	(c) Multiple processes
(iv) Separating a mixture of sand and salt	(d) Glass rod
(v) Heat a solution	(e) Sieving

Answer:

The correct table is shown below:

Column A	Column B
(i) Winnowing	(b) Wind
(ii) Stir the mixture	(d) Glass rod
(iii) Separate bran from flour	(e) Sieving
(iv) Separating a mixture of sand and salt	(c) Multiple processes
(v) Heat a solution	(a) Bunsen burner

Fill in the blanks:

evaporation, sizes, gravity, ice, filtration

(a) In sedimentation the heavier particles sink to the bottom by force of _________.

(b) To condense steam into water we must use _________.

(c) The method of _________ is used for preparing paneer.

(d) _________ is the process by which a liquid changes into vapour when it is heated.

(e) Sieving is used for mixtures which have components of different _________.

Answer:

(a) In sedimentation the heavier particles sink to the bottom by force of gravity.

(b) To condense steam into waterwe must use ice.

(c) The method of filtration is used for preparing paneer.

(d) Evaporation is the process by which a liquid changes into vapour when it is heated.

(e) Sieving is used for mixtures which have components of different sizes.

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