Methods of Separation in Everyday Life Class 6 Question Answer Science Chapter 9

Methods of Separation in Everyday Life Class 6 Questions and Answers NCERT Solutions

Class 6 Science Chapter 9 Methods of Separation in Everyday Life Question Answer

Methods of Separation in Everyday Life Class 6 Intext Questions

Page – 165
Question 1.
A small amount of puffed rice is mixed with chana dal. Can you think of separating the mixture by any method other than hand-picking?
Answer:
Yes, We can separate a mixture of puffed rice and chana dal using methods other than hand-picking.
Since puffed rice is lighter than chana dal, you can use a fan or blow air to separate them. The puffed rice, being lighter, will get blown away, while the heavier chana dal remains.

Page – 166

Question 1.
Valli is unable to separate husk from rice in a closed room. How can you help her?
Answer:
She can use two methods to separate husk from rice in a closed room:
(i) Sieving
Sieving effectively separates husk from rice based on size, with the husk passing through the sieve and rice remaining on top.

(ii) Winnowing
Winnowing separates husk from rice based on weight and airflow, with the husk being blown away and the rice remaining in the tray.

Page-167

Question 1.
Have you ever observed sieves being used at construction sites to separate pebbles and stones from the sand?
Answer:
Yes, I have seen sieves being used at construction sites to separate pebbles and stones from sand.
Sieves are a common tool in construction and other industries. They work by using a mesh or screen with specific holes to filter out materials of different sizes. In the case of construction, sieves are used to separate larger particles like pebbles and stones from finer materials like sand.

Page – 168

Question 1.
Have you ever observed white patches on the darkcoloured clothes you wear during hot summers? How are these patches formed?
Answer:
Yes, I have noticed white patches on dark-coloured clothes during hot summers. These patches are often referred to as salt stains or efflorescence.
How they form:
During hot weather, our bodies sweat to cool down. This sweat contains salts, primarily sodium chloride.

• As the sweat evaporates, the salts are left behind on the fabric.
• Over time, the salt concentration on the fabric increases.
• When the salt concentration becomes high enough, it can crystallise, forming visible white patches.

Page-169

Question 1.
Observe the figure. Does it answer the question? Can you name the process involved?

Answer:
Yes it answers the question. The process involved is condensation.

Page-170

Question 1.
In the chapter ‘Materials Around Us’, you have studied that oil does not mix with water and forms a separate layer when left undisturbed for some time. Which method of separation would you use to separate oil and water?
Answer:
Decantation process

Methods of Separation in Everyday Life Class 6 Textbook Questions

Question 1.
What purpose does hand-picking serve in the process of separation?
(a) Filtration
(b) Sorting
(c) Evaporation
(d) Decantation
Answer:
Option (b) is correct.
Explanation: Hand-picking is used to sort or remove unwanted materials from a mixture based on visible differences, like size or cqlour.

Question 2.
Which of the following substances are commonly separated using the churning method?
(a) Oil from water
(b) Sand from water
(c) Cream from milk
(d) Oxygen from air
Answer:
Option (c) is correct.
Explanation: Churning is used to separate cream from milk by agitating it, which causes the fat in the cream to separate.

Question 3.
Which factor is usually essential for the filtration?
(a) Apparatus size
(b) Presence of air
(c) Pore size
(d) Temperature of the mixture
Answer:
Option (c) is correct.
Explanation: The pore size of the filter determines which particles will be retained and which will pass through it.

Question 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. [T]
Reason: Evaporation of water leaves the salt behind.

(ii) Hand-picking should be used only when the quantity of one component is less. [T]
Reason: Hand-picking is practical when the quantity of the material to be picked is relatively small.

(iii) A mixture of puffed rice and rice grains can be separated by threshing. [F]
Correction: Threshing is used for separating grains from stalks. Puffed rice and rice grains can be separated by sieving or winnowing.

(iv) A mixture of mustard oil and lemon water can be separated by decantation. [F]
Correction: Mustard oil and lemon water can be separated by using a separating funnel or centrifugation, not decantation.

(v) Sieving is used to separate a mixture of rice flour and water. [F]
Correction: Sieving is used to separate solid particles from a mixture, but rice flour and water require filtration or decantation to separate.

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

Answer:

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

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 have settled at the bottom of the container, and you can separate the liquid without disturbing the settled solids. It’s useful for separating a mixture of sand and water or oil from water.

Question 7.
Can you relate the presence of nasal hair to any separation process?
Answer:
Nasal hair acts as a filter, similar to a sieve, trapping dust and other particles from the air we breathe, thereby preventing them from entering the lungs.

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:
Masks are generally made of multiple layers of fabric or non-woven materials like polypropylene. Their role is to filter out airborne particles and droplets, reducing the spread of viruses and protecting the wearer and others.

Question 9.
A mixture containing potatoes, salt and sawdust has been given to you. Outline a stepwise procedure for separating each component from this mixture.
Answer:
(i) Hand-picking: Remove the potatoes from the mixture by hand.
(ii) Sieving: Use a sieve to separate the sawdust from the salt.
OR
(iii) Dissolving and filtration: Dissolve the mixture of salt and sawdust in water and then filter the mixture to separate the salt from the sawdust.
(iv) Evaporation: Evaporate the water from the salt solution to recover the salt.

Question 10.
Read the following story titled ‘Intelligent Leela’ and tick the most appropriate options. Provide a suitable title of your choice for the paragraph.
Answer:
Leela was working on 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/bojled 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.

Methods of Separation in Everyday Life Class 6 NCERT Exemplar Questions

Multiple Choice Questions

Question 1.
Paheli bought some vegetables such as French, French beans, lady’s finger, green chillies, brinjals and potatoes, all mixed in a bag. Which of the following methods of separation would be most appropriate for her to separate them?
(a) Winnowing
(b) Sieving
(c) Threshing
(d) Hand-picking
Answer:
(d) Hand-picking
Explanation: Hand-picking is the best method for separating the vegetables because they are big in size.

Question 2.
Boojho’s grandmother is suffering from diabetes. Her doctor advised her to take ‘lassi’ with less fat content. Which of the following methods would be most appropriate for Boojho to prepare it?
(a) Filtration
(b) Decantation
(c) Churning
(d) Winnowing
Answer:
(c) Churning
Explanation: By churning curd, the butter (fat) is separated that can be removed and the remaining lassi contains less fat content.

Question 3.
Which of the following mixtures would you be able to separate using the method of filtration?
(a) Oil in water
(b) Cornflakes in milk
(c) Salt in water
(d) Sugar in milk
Answer:
(b) Cornflakes in milk
Explanation: Cornflakes are insoluble in milk and hence can be separated by filtration.

Question 4.
Which of the following methods would be most. appropriate to separate grains from bundles of stalks?
(a) Hand-picking
(b) Winnowing
(c) Sieving
(d) Threshing
Answer:
(d) Threshing
Explanation: Threshing results in the separation of grains from stalks.

Question 5.
Four mixtures are given below:
(i) Kidney beans and chickpeas
(ii) Pulses and rice
(iii) Rice flakes and corn
(iv) Potato wafers and biscuits
Which of these can be separated by, the method of winnowing?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)
Answer:
(d) (iii) and (iv)
Explanation: Mixtures of rice flakes and corn and potato wafers and biscuits can be separated by winnowing because there is a difference in the weight of the two components one being lighter and the other being heavier.

Question 6.
While preparing chapatis, Paheli found that the flour to be used was mixed with wheat grains. Which out of the following is the most suitable method to separate the grains from the flour?
(a) Threshing
(b) Sieving
(c) Winnowing
(d) Filtration
Answer:
(b) Sieving
Explanation: Flour can be separated from wheat grains by sieving due to the difference in the size of flour and grain. Wheat grain will not pass through the sieve.

Question 7.
You might have observed the preparation of ghee from butter and cream at home. Which method(s) can be used to separate ghee from the residue?
(i) Evaporation
(ii) Decantation
(iii) Filtration
(iv) Churning
Which of the following combinations is the correct answer?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (iv) only
Answer:
(b) (ii) and (iii)
Explanation: Decantation and filtration can be used to separate ghee (which is in liquid form) from the residue (which is in solid form).

Question 8.
In an activity, a teacher dissolved a small amount of solid copper sulphate in a tumbler half-filled with water. Which method would you use to get solid copper sulphate back from the solution?
(a) Decantation
(b) Evaporation
(c) Sedimentation
(d) Condensation
Answer:
(b) Evaporation
Explanation: When the solution of copper sulphate is evaporated, water evaporates, leaving behind the solid copper sulphate.

Question 9.
During summer, Boojho carries water in a transparent plastic bottle to his school. One day, he left his bottle in the school. The bottle still had some water left in it. The following day, he observed some water droplets on the inner surface of the empty portion of the bottle. These droplets of water were formed due to
(a) boiling and condensation.
(b) evaporation and saturation.
(c) evaporation and condensation.
(d) condensation and saturation.
Answer:
(c) evaporation and condensation.
Explanation: Due to high temperatures in the summers, the water gets heated in plastic bottles and evaporates. The vapours hit the lid of the bottle and condensed it to form water droplets, which are collected on the empty portion of the bottle.

Question 10.
Paheli asked for a glass of water from Boojho. He gave her a glass of ice-cold water. Paheli observed some water droplets on the outer surface of the glass and asked Boojho how these droplets of water were formed. Which of the following should te Boojho’s answer?
(a) Evaporation of water from the glass
(b) Water that seeped out from the glass
(c) Evaporation of atmospheric water vapour
(d) Condensation of atmospheric water vapour
Answer:
(d) Condensation of atmospheric water vapour
Explanation: When the air touches the surface of ice-cold glass, the water vapours of the atmosphere are condensed to form water droplets on the outer surface of the glass.

Very Short Answer Type Questions

Question 11.
Sheela, Saima and Ravi have to dissolve the maximum amount of sugar in the same amount of milk so as to win in a game. Ravi took hot boiling milk, while Saima took ice-cold milk. Sheela managed to get milk at room temperature. Who do you think would win the game and why?
Answer:
The solubility of solids in liquids increases with temperature. Saima will be able to dissolve a minimum amount of sugar in ice-cold milk. Sheela will be able to dissolve more sugar than Saima since the milk is at room temperature. Ravi would win the game because he would be able to dissolve the maximum amount of sugar in hot boiling milk.

Question 12.
Fill in the blanks with appropriate words.
(i) Small pieces of stone can be removed from rice by _______.
(ii) _______ are obtained from stalks by threshing.
(iii) Husk from wheat flour is generally removed by _______.
(iv) The process of settling of heavier particles is called _______.
(v) Filtration is helpful in separating an insoluble _______ from a _______.
Answer:
(i) Hand-picking
(ii) Grains
(iii) Sieving
(iv) Sedimentation
(v) Solid and liquid

Question 13.
State whether the following statements are true or false.
(a) A mixture of pil and water can be separated by filtration.
(b) Water can be separated from salt by evaporation.
(c) A mixture of wheat grains and wheat flour can be separated by sieving.
(d) A mixture of iron filings and rice flour can be separated by a magnet.
(e) A mixture of wheat grains and rice flakes can be separated by winnowing.
(f) A mixture of tea leaves and milk can be separated by decantation.
Answer:
(a) False
Explanation: A mixture of oil and water can be separated by a separating funnel.
(b) True
(e) True
(c) True
(f) True
(d) True

Short Answer Type Questions

Question 14.
Name and briefly describes a method that can be helpful in separating a mixture of husk from grains. What is the principle of this method?
Answer:
Husk can be separated from grains by the process of winnowing. When the mixture is allowed to fall down from a height, the lighter husk is carried away by air and falls on the ground. This method is based on the principle that in a mixture with components of different weights, the lighter particles are blown away by wind.

Question 15.
Match the mixtures in column I with their method of separation in column II.

Column 1	Column II
(a) Oil mixed in water	(i) Sieving
(b) Iron powder mixed with flour	(ii) Hand-picking
(c) Salt mixed with water	(iii) Decantation
(d) Lady’s finger mixed with French beans	(iv) Magnet
(e) Rice flour mixed with kid-ney beans	(v) Evaporation

Answer:

Column 1	Column II
(a) Oil mixed in water	(iii) Decantation
(b) Iron powder mixed with flour	(iv) Magnet
(c) Salt mixed with water	(v) Evaporation
(d) Lady’s finger mixed with French beans	(ii) Hand-picking
(e) Rice flour mixed with kid-ney beans	(i) Sieving

Long Answer Type Questions

Question 16.
Both Sarika and Mohan were asked to make salt solutions. Sarika was given a teaspoonful of salt and half a glass of water, whereas Mohan was given 20 teaspoons of salt and half a glass of water.
(a) How would they make salt solutions?
(b) Who would be able to prepare a saturated solution?
Answer:
(a) Sarik: Sarika can easily dissolve her teaspoonful of salt in half a glass of water to make a salt solution. Since the amount of salt is small compared to the water, it will dissolve completely, forming an unsaturated solution.
Mohan: Mohan will add 20 teaspoons of salt to half a glass of water. As he adds salt, it will dissolve until the water can no longer hold more salt. At that point, the remaining salt will not dissolve and will settle at the bottom, indicating that the solution has reached saturation.

(b) Mohan would be able to prepare a saturated solution. Because he was given a much larger quantity of salt, the water will eventually reach its saturation point where no more salt can dissolve, forming a saturated solution. Sarika’s solution will remain unsaturated since she has only a small amount of salt.

Question 17.
Paheli was feeling thirsty, but there was only a pot of water at home which was muddy and unfit for drinking. How do you think Paheli would have made this water fit for drinking if the following materials were available to her?
[Alum, tub, muslin cloth, gas stove, thread, pan and lid]
Answer:
With the materials pvailable to Paheli-alum, tub, muslin cloth, gas stove, thread, pan and lid-she could undertake the following steps to purify water:

• Filter the muddy water with the help of muslin cloth.
• Tie the piece of alum with thread, sink it in water for some time and then leave the water undisturbed.
• After some time, the impurities will settle down and the water from the top can be decanted.
• Boil the decanted water for about 10 minutes in a covered pan on a gas stove. Cool and filter the water
• The filtered water is fit for drinking.

Question 18.
Read the story titled ‘WISE FARMER’ and tick the correct option to complete the story.
A farmer was sad/happy to see his healthy wheat crop ready for harvest. He harvested the crops and left them under the sun/rain to dry the stalks. To separate the seeds from the bundles of the stalk, he hand-picked/threshed them. After gathering the seed grains, he wanted to separate the stones and husk from it. His wife winnowed/ threshed them to separate the husk and later sieved/ hand-picked to remove stones from it. She ground the wheat grains and sieved/filtered the flour. The wise farmer and his wife got a good price for the flour. Can you tell me why?
Answer:

• happy
• sun
• threshed
• winnowed
• hand-picked
• sieved

The wise farmer and his wife got a good price for the flour because they used appropriate methods of separation to get good quality of flour.

Hand-picking

• Description: Manual separation of visible impurities or unwanted materials from a mixture using hands.
• Principle: Differences in size, colour and shape.
• Example: Removing stones from rice or wheat.
• Advantages: Simple and cost-effective for small quantities.
• Limitations: Not suitable for large quantities or when particles are very similar in size.

Everyday Life Example:

• Activity: Hand-pick stones from a mixture of grains.
• Procedure: Spread out the grains and pick out stones by hand.
• Observation: Stones are distinguishable from grains.
• Advantage: It is effective for small amounts and clearly visible particles.

Threshing

• Description: Physical process to separate grains from stalks by beating or rubbing.
• Principle: Difference in texture and rigidity between grains and stalks.
• Example: Beating wheat stalks to release the grains.
• Advantages: Efficient for large-scale grain processing.
• Limitations: Labour and space-intensive.

Everyday Life Example:

• Activity: Observe traditional threshing.
• Procedure: Beat the stalks against a hard surface (wood log) or use a threshing machine.
• Observation: Grains fall away from the stalks.
• Advantage: Threshing is effective in large-scale grain separation.

Winnowing

• Description: Using air to separate lighter particles (like husk) from heavier particles (like grains).
• Principle: Differences in weight.
• Example: Separating husk from grains using a winnowing basket.
• Advantages: Effective for separating light impurities from heavier grains.
• Limitations: Requirement of wind or a fan.

Activity 9.1 (Page-165)

Let Us Explore

Activity 9.1 explores the concept of separating components of a mixture based on their weight using blowing air. This concept is applied traditionally in agriculture to separate grains from husks.

Question 1.
Take a handful of roasted peanuts and rub them between your palms. What happens?
Answer:
When you rub roasted peanuts between your palms, the skin of the peanuts comes off and can be separated from the peanuts themselves. This demonstrates how friction can help in removing outer layers from food items.

Question 2.
Is it possible to separate the removed skin and the peanuts?
Answer:
Yes, it is possible to separate the skins from the peanuts. The skins, being lighter, can be separated from the peanuts by blowing air or by using other methods of separation.

Question 3.
Now, try blowing it. What do you observe? Which of these components-removed peanut skins or peanuts-are blown away?
Answer:
When you blow air on the mixture of peanuts and their skins, you will observe that the lighter peanut skins are blown away, while the heavier peanuts remain in place. This shows that blowing air can help separate lighter components from heavier ones.

Question 4.
How do you think farmers separate so many grains from husk?
Answer:
Farmers traditionally use a soop (bamboo tray) to separate grains from husk. By moving the tray in the direction of the wind, the lighter husk is blown away, while the heavier grains fall directly down into the tray. This method uses the wind to help in the separation process.

Question 5.
What do you infer from Fig. 9.4? Do both the components, wheat grains and husk, fall in the same place? Which of the two components gets blown away? Can the wind separate the two components?
Answer:
From Fig. 9.4, you can infer that when the farmer moves the bamboo tray containing threshed wheat grains in the direction of the wind, the lighter husk gets blown away,*while the heavier wheat grains fall at the same place. The wind effectively separates the lighter husk from the heavier grains, demonstrating the principle of separating components based on their weight and using wind as a tool.

Sieving

• Description: Using a sieve to separate particles based on size.
• Principle: Differences in particle size.
• Example: Sifting flour to remove bran.
• Advantage: Precise separation based on size.
• Limitations: Limited to particle size differences.

Everyday Life Example:

• Activity: Sift flour to, remove bran.
• Procedure: Pass flour through a sieve or mesh.
• Observation: Fine flour passes through, while bran is left behind in the sieve.
• Advantage: It is effective for size-based separation.

Evaporation

Evaporation

• Description: Removing a liquid to obtain the dissolved solute by heating.
• Principle: Differences in boiling points.
• Example: Extracting salt from seawater.
• Advantages: Simple and effective for obtaining solid solutes.
• Limitations: Requirement of heat and time; not suitable for heat-sensitive substances.

Activity 9.2 (Page-168)

Let Us Observe and Create

This activity explores the process of crystallisation, where a dissolved substance (salt) forms solid crystals as the solvent (water) evaporates. We will observe the formation of salt crystals on a dark-coloured paper after applying a salt solution ahd allowing it to dry.

Activity Steps

1. Prepare a salt solution by dissolving salt in water.
2. Apply a few drops of the salt solution onto a darkcoloured paper.
3. Allow the solution to dry completely.
4. Observe the paper.

Question 1.
What do you observe on the paper after the salt solution dries?
Answer:
We observed white patches or crystals on the paper where the salt solution was applied.

Question 2.
What is the substance that forms the white patches?
Answer:
The white patches are composed of salt crystals that form as the water from the solution evaporates.

Question 3.
How does the salt solution change as the water evaporates?
Answer:
As the water evaporates, the concentration of the salt solution increases. This higher concentration eventually leads to the formation of salt crystals.

Question 4.
Whalf factors might influence the appearance and size of the salt crystals?
Answer:
Factors that might influence the appearance and size of the salt crystals include the following:

• Concentration of the salt solution: A higher concentration of salt can lead to larger and more numerous crystals.
• Type of paper: The texture and absorbency of the paper can affect the formation and appearance of the crystals.
• Drying conditions: The temperature, humidity and airflow can influence the evaporation rate and the crystal formation.

Activity 9.3 (Page-169)

Let Us Investigate

Introduction: This activity demonstrates how to retrieve salt from a salt solution by evaporating the water. It helps understand the separation of solutes from solvents through the process of evaporation.

Question 1.
What do you observe after the salt solution is boiled and the china dish is allowed to cool? What is left in the china dish? Did you get the salt back?
Answer:

• Observation: After boiling the salt solution and allowing the china dish to cool, salt crystals will be left in the dish.
• What is left? The salt is left in the china dish after the water evaporates.
• Retrieve the salt: Yes, you can get the salt back and feel its presence by touching the residue in the dish.

Question 2.
Is there any method through which I can retrieve both salt and water?
Answer:
Yes, you can retrieve both salt and water using a method called distillation. Here’s how it works:
Distillation Process

• Set-up: Use a distillation apparatus, which typically includes a boiling flask, a condenser and a receiving flask.
• Boiling: Heat the salt solution in the boiling flask. The water will evapobate, leaving the salt behind.
• Condensation: The water vapour rises through a tube to the condenser, where it cools down and condenses back into liquid water.
• Collection: Collect the condensed water in the receiving flask. The salt remains in the boiling flask, while the water is recovered in its pure form.

Summary

• Salt: Remains in the boiling flask after the evaporation.
• Water: Gets collected as condensed vapour in the receiving flask.

Sedimentation and Decantation

• Description: Allow solids to settle at the bottom and then pour off the clear liquid.
• Principle: Differences in density.
• Example: Separating tea leaves from brewed tea.
• Advantages: Simple for separating large solids from liquids.
• Limitations: Not effective for very fine particles.

Everyday Life Example:

• Activity: Allow tea to settle and decant.
• Procedure: Let tea leaves settle and then pour off the clear tea.
• Observation: Leaves settle at the bottom; clear tea is decanted.
• Advantage: It is useful for separating larger solids from liquids.

Filtration

• Description: Using a filter to separate solids from liquids.
• Principle: Differences in particle size.
• Example: Filtering muddy water using filter paper.
• Advantages: Precise separation of particles based on size.
• Limitations: Filter paper getting clogged with large amounts of solid.

Activity 9.4 (Page-171)

Let us Experiment

Try to fold the filter paper yourself and make a cone as shown in Fig. 9.10.

Place it inside a funnel kept on a conical flask and pour muddy water into it (see Fig. 9.11).

Question 1.
What do you observe? Do the mud particles pass through the filter paper?
Answer:
The water coming from the funnel will be collected in the conical flask. You will get mud as a residue on the filter paper and clear water as a filtrate in the conical flask.

Activity 9.5 (Page-172)

Let Us Design and Create

Objective: To create a simple water filter to remove unwanted substances from pond water using low-cost materials.
Materials Needed:

• Plastic bottle
• Scissors
• Coffee filter or cheesecloth
• Sand
• Activated charcoal
• Gravel
• Cotton balls
• Rubber band
• Container for filtered water

Steps:
Prepare the bottle:

• Cut the bottom off the plastic bottle.
• Place the coffee filter or cheesecloth at the neck of the bottle and secure it with a rubber band.

Add filtering layers:

• Add a layer of cotton balls on top of the coffee filter.
• Add a layer of activated charcoal on top of the cotton balls.
• Add a layer of sand on top of the charcoal.
• Finally, add a layer of gravel on top of the sand.

Filter the water:

• Pour the pond water through the filter.
• Collect the filtered water in a container.

Observation:

• Observe the clarity of the filtered water compared to the pond water.

Questions:

Question 1.
What do you observe after filtering the water?
Answer:
The filtered water is clearer and has fewer visible particles compared to the pond water.

Question 2.
How does the filter work?
Answer:
The cotton balls trap large particles, the charcoal adsorbs impurities and odours, the sand filters out smaller particles and the gravel helps prevent clogging of the sand.

Question 3.
What are the components of the filter?
Answer:
Coffee filter, cotton balls, activated charcoal, sand and gravel.

Churning

Churning is the process of stirring or agitating a liquid, such as a curd (yoghurt), to separate its components. In the process of making butter, churning involves vigorously mixing curd to separate butterfat from buttermilk. The mechanical agitation causes the fat molecules to clump together, forming butter, while the remaining liquid becomes buttermilk. Churning can be done manually with a churner or mechanically with an electric churner.

Question 1.
Can you name one kitchen appliance which runs on electricity that is used to prepare buttermilk?
Answer:
One kitchen appliance that runs on electricity and can be used to prepare buttermilk is an electric blender or mixer grinder. It helps in churning curd to separate the butter and make buttermilk.

Magnetic Separation

Magnetic Separation

• Description: Using a magnet to attract magnetic materials away from non-magnetic materials.
• Principle: Magnetic properties of substances.
• Example: Separating iron nails from sawdust.
• Advantages: Quick and efficient for magnetic materials.
• Limitations: Only applicable to magnetic substances.

Everyday Life Example:

• Activity: Use a magnet to separate iron nails from sawdust.
• Procedure: Move the magnet through the sawdust to attract iron nails.
• Observation: Iron nails are attracted to the magnet.
• Change it into Advantage: It is effective for separating magnetic substances.

Question 1.
What method of separation did the carpenter use to pick up iron nails from sawdust?
Answer:
The carpenter used magnetic separation. Magnetic separation involves using a magnet to attract magnetic substances, like iron, from a mixture.

Activity 9.6 (Page-175)

Let Us Play

Objective: To identify and classify different methods of separating substances based on their purpose.
Materials Needed:
Small slips of paper with the following phrases written on them:

1. Separating small stones from pulses.
2. Churning curd to obtain butter.
3. Taking out green chillies from cooked dalia or poha.
4. Taking out seeds from watermelon.
5. Sorting piles of sawdust and iron nails from a mixed heap of building material.
6. Picking marigold flowers from a heap of other flowers to make a garland.
7. Separating pebbles from sand.
8. Separating coconut pieces from rice flour.
9. Separating oil from water.
10. Separating salt from salt solution.

Two baskets (or containers) labelled with two different purposes: ‘Physical Separation’ and ‘Chemical Separation’.

Instructions:

1. Divide into teams:

• Split into two teams.

2. Sort the slips:

• Each team takes turns picking a slip from the pile and decides into which basket (Physical Separation or Chemical Separation) the method should go.
• Physical separation includes methods that use physical processes (e.g, sieving, hand-picking).
• Chemical separation includes methods that involve chemical changes or processes (e.g., evaporation, distillation).

3. Discuss and explain:

• Each team explains why they classified the method under the chosen category.

Examples:

• Physical separation: Separating small stones from pulses (sieving) and picking marigold flowers (handpicking)
• Chemical separation: Separating salt from salt solution (evaporation)

4. Compare results:

• After sorting, compare the baskets to see which team has the most accurate classifications.

Keywords

• Hand-picking: A method of separation where particles are manually selected from a mixture based on size, shape or colour, often used for removing small impurities from food grains
• Threshing: The process of separating grains from the stalks of crops by beating or striking. commonly used in agriculture to harvest cereals
• Winnowing: A technique that uses wind or air to separate lighter components, such as husk, from heavier components, such as grains, typically using a bamboo tray or similar tool
• Sieving: A method where a sieve with varying hole sizes is used to separate particles of different sizes, allowing fine particles to pass through while retaining larger ones
• Filtration: A separation process where a filter paper or other porous material is used to separate solid particles from a liquid, allowing the liquid to pass through while trapping the solids.

Curiosity Class 6 Science Book Solutions