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Chapter 9. Methods of Separation in Everyday Life

Chapter Review

Chapter 9. Methods of Separation in Everyday Life

Chapter Review

In our daily life, many substances are found mixed together. Before using these substances, we often need to separate useful materials from unwanted ones or separate two useful substances from each other. Farmers separate grains from husk, cooks remove stones from pulses, people strain tea leaves from tea, and salt is obtained from seawater. All these are examples of different methods of separation. Choosing the correct method depends on the physical properties of the substances, such as size, weight, shape, solubility, and magnetic nature.

Introduction

Separation is the process of removing one or more components from a mixture. It helps us obtain pure, useful, and safe substances for everyday use. Different separation methods are used according to the type of mixture and the properties of its components.

Why Do We Separate Substances?

Substances are separated mainly for two purposes:

• To remove unwanted or harmful impurities.
• To separate two or more useful substances.

Examples:

• Removing stones from rice.
• Separating butter from curd.
• Obtaining salt from seawater.
• Removing tea leaves from prepared tea.

What is a Mixture?

A mixture is formed when two or more substances are combined physically without any chemical change. The components of a mixture can usually be separated by suitable physical methods.

Methods of Separation

The chapter introduces several commonly used methods of separation that are used in homes, farms, laboratories, and industries.

Method	Used For
Handpicking	Removing large unwanted particles by hand.
Threshing	Separating grains from harvested stalks.
Winnowing	Separating lighter husk from heavier grains using wind.
Sieving	Separating particles of different sizes.
Evaporation	Obtaining dissolved solids from a solution.
Sedimentation	Allowing heavier insoluble particles to settle.
Decantation	Pouring off the clear liquid carefully.
Filtration	Separating insoluble solids from liquids.
Churning	Separating butter from curd.
Magnetic Separation	Separating magnetic materials using a magnet.

Selection of a Separation Method

No single method can separate every mixture. The appropriate method depends upon the properties of the substances present in the mixture.

Property	Suitable Method
Difference in size	Handpicking, Sieving
Difference in weight	Winnowing
Difference in magnetic property	Magnetic Separation
Difference in solubility	Filtration, Evaporation
Settling tendency	Sedimentation and Decantation

Applications in Everyday Life

Methods of separation are useful in many daily activities.

• Cleaning food grains before cooking.
• Preparing flour using a sieve.
• Making tea using a strainer.
• Obtaining common salt from seawater.
• Separating butter from curd.
• Cleaning muddy water using filters.
• Removing iron pieces from waste materials.

Importance of Separation

• Improves the quality of food.
• Removes harmful impurities.
• Helps in recycling useful materials.
• Supports agriculture and industries.
• Provides clean water and pure substances.
• Reduces wastage of useful materials.

Important Terms

Term	Meaning
Mixture	Combination of two or more substances.
Handpicking	Removing unwanted particles by hand.
Threshing	Separating grains from stalks.
Winnowing	Separating lighter particles using wind.
Sieving	Separating particles based on size.
Evaporation	Changing a liquid into vapour to recover dissolved solids.
Sedimentation	Settling of heavier insoluble particles.
Decantation	Carefully pouring out the clear liquid.
Filtration	Separating insoluble solids using a filter.
Filtrate	Liquid collected after filtration.
Residue	Solid left on the filter.
Churning	Separating butter from curd.
Magnetic Separation	Separating magnetic substances using a magnet.

Chapter Highlights

• Mixtures contain two or more substances mixed together.
• Different mixtures require different separation methods.
• Handpicking is suitable for removing visible impurities.
• Threshing separates grains from harvested crops.
• Winnowing uses moving air to separate lighter particles.
• Sieving separates solids of different particle sizes.
• Evaporation helps recover dissolved solids such as salt.
• Sedimentation and decantation separate insoluble solids from liquids.
• Filtration removes insoluble impurities using filter media.
• Churning separates butter from curd.
• Magnets separate magnetic substances from non-magnetic materials.
• Methods of separation play an important role in homes, farms, industries, and environmental protection.

Chapter 9. Methods of Separation in Everyday Life

NCERT TextBookn Questions With Answers

Chapter 9. Methods of Separation in Everyday Life

NCERT Textbook Exercise

The following solutions are prepared according to the latest NCERT Curiosity (Class 6 Science) textbook. The answers are written in simple English, keeping the CBSE pattern in mind to help students understand the concepts clearly and perform well in examinations.

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

Options:

(i) Filtration

(ii) Sorting

(iii) Evaporation

(iv) Decantation

Answer: (ii) Sorting

Explanation: Handpicking is used to remove unwanted solid particles such as stones or husk from grains by picking them with the hand.

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

Options:

(i) Oil from water

(ii) Sand from water

(iii) Cream from milk

(iv) Oxygen from air

Answer: (iii) Cream from milk

Explanation: Churning is commonly used to separate butter or cream from curd or milk.

Question 3. Which factor is usually essential for filtration?

Options:

(i) Apparatus size

(ii) Presence of air

(iii) Pore size

(iv) Temperature of the mixture

Answer: (iii) Pore size

Explanation: A filter works because its pores allow the liquid to pass while trapping insoluble solid particles.

Question 4. State with reason whether the following statements are True or False. Correct the false statements.

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

Answer: True.

Reason: Water evaporates in sunlight, leaving salt behind.

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

Answer: True.

Reason: Handpicking is suitable only when the unwanted particles are present in small amounts and are easily visible.

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

Answer: False.

Correct Statement: A mixture of puffed rice and rice grains can be separated by handpicking or winnowing, not by threshing.

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

Answer: True.

Reason: Oil and water do not mix. After settling, the upper oil layer can be separated by decantation.

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

Answer: False.

Correct Statement: Sieving is used to separate solid particles of different sizes. Rice flour mixed with water cannot be separated by sieving.

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

Column I	Correct Method
Gram flour mixed with black gram	Sieving (d)
Chalk powder mixed with water	Filtration (e)
Corn mixed with potatoes	Handpicking (a)
Iron powder mixed with sawdust	Magnetic Separation (b)
Oil mixed with water	Decantation (c)

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

Answer:

Decantation is used when the solid particles are heavy and settle at the bottom after keeping the mixture undisturbed for some time. The clear liquid is then poured carefully into another container. It is commonly used for separating muddy water or washing rice and pulses.

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

Answer:

Yes. Nasal hair acts like a natural filter. It traps dust, pollen, and other harmful particles present in the air before they enter our lungs. This process is similar to filtration.

Question 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?

Answer:

Most masks are made of multiple layers of non-woven fabric or special filtering material.

The masks:

• Filter dust, germs, and tiny droplets.
• Reduce the spread of viruses and bacteria.
• Protect both the wearer and nearby people from infections.

Explanation: Like a filter paper, the mask allows air to pass while trapping harmful particles.

Chapter 9. Methods of Separation in Everyday Life

Extra Questions Examination Based

Chapter 9. Methods of Separation in Everyday Life

The following important questions are prepared according to the latest CBSE pattern and NCERT Curiosity textbook. These questions include competency-based, conceptual, and examination-oriented questions for better practice.

Important Questions with Answers

Practice these questions regularly to strengthen your understanding of different methods of separation used in everyday life.

1 Mark Questions

Answer each question in one sentence.

Question 1. What is a mixture?

Answer: A mixture is a physical combination of two or more substances.

Question 2. Which method is used to remove stones from rice?

Answer: Handpicking.

Question 3. Which method is used to separate husk from grains?

Answer: Winnowing.

Question 4. What is the purpose of sieving?

Answer: It separates particles of different sizes.

Question 5. Which method is used to separate butter from curd?

Answer: Churning.

Question 6. What is filtration?

Answer: Filtration is the process of separating insoluble solids from liquids using a filter.

Question 7. Which method is used to obtain salt from seawater?

Answer: Evaporation.

Question 8. Which instrument is used in magnetic separation?

Answer: A magnet.

Question 9. What is sedimentation?

Answer: It is the process in which heavier insoluble particles settle at the bottom of a liquid.

Question 10. Name one natural filter present in our body.

Answer: Nasal hair.

2 Marks Questions

Answer each question in about 30–40 words.

Question 1. Why is separation of substances necessary?

Answer: Separation helps remove unwanted impurities, obtain useful substances, improve quality, and make materials safe for use.

Question 2. Differentiate between handpicking and sieving.

Answer:

Handpicking	Sieving
Done manually.	Uses a sieve.
Suitable for large visible impurities.	Suitable for particles of different sizes.

Question 3. What is the difference between sedimentation and decantation?

Answer: Sedimentation allows heavy particles to settle at the bottom, while decantation is the careful pouring of the clear liquid from above the settled particles.

Question 4. Why is filtration better than decantation in some cases?

Answer: Filtration removes even very fine insoluble particles, whereas decantation cannot remove small suspended impurities completely.

Question 5. Give any two examples of magnetic separation.

Answer:

• Separating iron filings from sand.
• Removing iron pieces from scrap materials.

3 Marks Questions

Answer each question in about 50–70 words.

Question 1. Explain the process of winnowing.

Answer: Winnowing is used to separate lighter husk from heavier grains. The mixture is dropped from a height, and moving air blows away the lighter husk while the heavier grains fall straight down due to gravity.

Question 2. Explain the process of filtration with a suitable example.

Answer: In filtration, the mixture is passed through a filter paper or cloth. The liquid passes through as the filtrate, while insoluble solid particles remain on the filter as residue. Separating chalk powder from water is a common example.

Question 3. Describe the process of obtaining salt from seawater.

Answer: Seawater is collected in shallow ponds. Heat from the Sun causes water to evaporate slowly. After all the water evaporates, solid salt remains behind and is collected.

Question 4. Explain the working of magnetic separation.

Answer: A magnet attracts magnetic substances such as iron while non-magnetic substances remain behind. This method is useful for separating iron filings from mixtures.

Question 5. Describe the process of churning.

Answer: Churning is used to separate butter from curd. Continuous stirring causes fat particles to come together and float on the surface, where they can be collected easily.

Long Answer Questions

Answer the following questions in detail.

Question 1. Explain different methods of separation used in everyday life.

Answer:

Different methods of separation are used depending on the properties of the substances. Handpicking removes visible impurities, threshing separates grains from stalks, winnowing separates lighter husk from grains, sieving separates particles of different sizes, sedimentation and decantation separate heavier insoluble particles from liquids, filtration removes fine insoluble particles, evaporation recovers dissolved solids, churning separates butter from curd, and magnetic separation removes magnetic substances from mixtures.

Question 2. How do physical properties help in choosing the correct method of separation?

Answer:

The method of separation depends on differences in size, weight, shape, solubility, magnetic property, and density of the substances. For example, sieving depends on particle size, winnowing depends on weight, filtration depends on insolubility, and magnetic separation depends on magnetic properties.

Question 3. Explain sedimentation, decantation, and filtration with suitable examples.

Answer:

In sedimentation, heavy insoluble particles settle at the bottom of a liquid. During decantation, the clear liquid is carefully poured into another container. Filtration removes remaining insoluble particles using filter paper or cloth. For example, muddy water can first be allowed to settle, then decanted, and finally filtered to obtain cleaner water.

Question 4. Discuss the importance of separation methods in our daily life.

Answer:

Methods of separation help us obtain clean food, safe drinking water, pure substances, and useful materials. They are widely used in homes, agriculture, laboratories, industries, recycling plants, and water treatment systems. These methods improve health, reduce waste, and make many daily activities easier.

Question 5. Explain why no single method of separation can be used for every mixture.

Answer:

Different mixtures have different physical properties. Some mixtures differ in particle size, some in weight, some in solubility, while others differ in magnetic properties. Therefore, the method of separation must be selected according to the characteristics of the substances present in the mixture.

Chapter 9. Methods of Separation in Everyday Life

40 Important MCQs with Answers

Chapter 9. Methods of Separation in Everyday Life

The following multiple-choice questions are based on the latest NCERT Curiosity textbook and the CBSE competency-based pattern. They cover important concepts, applications, and daily-life situations related to methods of separation.

40 Important MCQs with Answer Key

Choose the correct answer for each question.

1. A mixture is a combination of

(A) One substance (B) Two or more substances (C) Only liquids (D) Only solids

2. Which method is used to remove stones from rice?

(A) Filtration (B) Handpicking (C) Evaporation (D) Churning

3. Which method separates grains from harvested stalks?

(A) Sieving (B) Winnowing (C) Threshing (D) Decantation

4. Winnowing separates substances based on differences in

(A) Colour (B) Weight (C) Shape (D) Smell

5. Which method is commonly used to separate flour from bran?

(A) Sieving (B) Churning (C) Filtration (D) Sedimentation

6. Filtration is mainly used to separate

(A) Two liquids (B) Insoluble solids from liquids (C) Salt from water (D) Husk from grain

7. Which method is used to obtain salt from seawater?

(A) Decantation (B) Evaporation (C) Churning (D) Winnowing

8. Which method is used to separate butter from curd?

(A) Filtration (B) Churning (C) Sieving (D) Handpicking

9. A magnet is used to separate

(A) Sand from water (B) Iron filings from sand (C) Rice from pulses (D) Salt from water

10. Which property is used in magnetic separation?

(A) Colour (B) Solubility (C) Magnetism (D) Density

11. Sedimentation is useful when

(A) Solids dissolve in water (B) Heavy insoluble particles settle down (C) Liquids mix completely (D) Grains are harvested

12. Decantation is done after

(A) Evaporation (B) Sedimentation (C) Sieving (D) Churning

13. Which material is commonly used as a filter?

(A) Plastic sheet (B) Filter paper (C) Glass plate (D) Aluminium foil

14. The liquid collected after filtration is called

(A) Residue (B) Sediment (C) Filtrate (D) Vapour

15. The solid left on the filter paper is called

(A) Filtrate (B) Residue (C) Solution (D) Mixture

16. Which of the following is a soluble substance?

(A) Sand (B) Chalk powder (C) Salt (D) Sawdust

17. Which method is suitable for separating sand from water?

(A) Filtration (B) Churning (C) Winnowing (D) Handpicking

18. Which method is used to separate tea leaves from tea?

(A) Evaporation (B) Filtration (C) Churning (D) Winnowing

19. Which process depends on the difference in particle size?

(A) Sieving (B) Churning (C) Evaporation (D) Magnetic separation

20. Which method is commonly used in flour mills?

(A) Sieving (B) Decantation (C) Churning (D) Sedimentation

21. Which mixture can be separated by handpicking?

(A) Rice and stones (B) Salt and water (C) Oil and water (D) Sugar solution

22. Which method requires moving air?

(A) Sieving (B) Winnowing (C) Churning (D) Filtration

23. Which of the following is an example of filtration?

(A) Making butter (B) Straining tea (C) Drying clothes (D) Harvesting crops

24. Which method removes dissolved water from salt solution?

(A) Evaporation (B) Sedimentation (C) Sieving (D) Churning

25. Which separation method is used in water purification plants?

(A) Filtration (B) Churning (C) Handpicking (D) Winnowing

26. Which mixture is best separated by magnetic separation?

(A) Sand and sugar (B) Iron filings and sand (C) Salt and sugar (D) Rice and wheat

27. Which process occurs before decantation?

(A) Condensation (B) Sedimentation (C) Churning (D) Sieving

28. Nasal hair works like

(A) A magnet (B) A filter (C) A sieve (D) A fan

29. Face masks mainly work on the principle of

(A) Filtration (B) Evaporation (C) Churning (D) Winnowing

30. Which method is NOT suitable for separating salt from water?

(A) Evaporation (B) Filtration (C) Crystallisation (D) Heating

31. Which method is used when one component is present in a very small quantity and is easily visible?

(A) Handpicking (B) Churning (C) Evaporation (D) Sedimentation

32. Which property helps in sieving?

(A) Difference in size (B) Difference in colour (C) Difference in smell (D) Difference in taste

33. Which method is commonly used by farmers after harvesting wheat?

(A) Threshing (B) Filtration (C) Churning (D) Evaporation

34. Which of the following is an insoluble substance?

(A) Sugar (B) Salt (C) Chalk powder (D) Jaggery

35. Which method is used to separate oil from water?

(A) Decantation (B) Sieving (C) Handpicking (D) Magnetic separation

36. Which separation method is based on density difference?

(A) Decantation (B) Handpicking (C) Sieving (D) Churning

37. Which of the following is NOT a method of separation?

(A) Winnowing (B) Photosynthesis (C) Filtration (D) Sieving

38. Which method is most suitable for separating muddy water?

(A) Sedimentation and filtration (B) Churning (C) Handpicking (D) Winnowing

39. Separation methods mainly depend upon the ________ of substances.

(A) Physical properties (B) Colour only (C) Smell only (D) Shape only

40. Which statement is correct?

(A) Every mixture can be separated by one method only.
(B) Different mixtures require different methods of separation.
(C) Filtration separates dissolved salt from water.
(D) Churning separates sand from water.

Answer Key

1-B, 2-B, 3-C, 4-B, 5-A, 6-B, 7-B, 8-B, 9-B, 10-C,
11-B, 12-B, 13-B, 14-C, 15-B, 16-C, 17-A, 18-B, 19-A, 20-A,
21-A, 22-B, 23-B, 24-A, 25-A, 26-B, 27-B, 28-B, 29-A, 30-B,
31-A, 32-A, 33-A, 34-C, 35-A, 36-A, 37-B, 38-A, 39-A, 40-B.