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Questions:

Generic 3

7 x 3 = 21

What happens when sand and powdered leaves are being fallen at the same place?

What is the principle of threshing?

Name and describe briefly a method which can be helpful in separating a mixture of husk from grains. What is the principle of this method?

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?

How will you separate sand and water from their mixture?

What is sieving? Where is it used?

What is winnowing? Where is it used?

Fill up / 1 Marks

5 x 1 = 5

Husk from wheat flour is generally removed by ____________________

Insects can be separated from wheat by __________________

10.

Tea leaves are separated from prepared tea by_______________

11.

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____________

12.

The method of separating seeds of paddy from its stalks is called __________

True or False

5 x 1 = 5

13.

A mixture of tea leaves and milk can be separated by decantation.

(a)

False

(b)

True

14.

A mixture of wheat grains and wheat flour can be separated by sieving.

(a)

False

(b)

True

15.

A mixture of chalk and water is separated by winnowing.

(a)

True

(b)

False

16.

A mixture of milk and water can be separated by filtration.

(a)

True

(b)

False

17.

Grain and husk can be separated by the process of decantation.

(a)

False

(b)

True

Generic 2

3 x 2 = 6

18.

What is the use of strainer?

19.

Write four materials that can be used for the process of filtration.

20.

Define the term condensation.

Generic 5

2 x 5 = 10

21.

Rohit and Raman are best friends. They study in different class but in the same standard, Class VI. One day, they were playing in the school. They were throwing sand on each other. Suddenly Raman asked to Rohit if we mix salt in sand, then how will you separate the mixture of sand and salt?
Rohit was quite intelligent, his science teacher had completed the chapter separation of substances last week. So, he immediately explained the method of separation. Rohit told him that his teacher had shown this activity in the class and same method is applicable for the separation of mixture of sugar and sand.
Read the passage carefully and answer the following questions:
(a) How a mixture of sand and salt is separated?
(b) Name the method(s) which are applicable in the separation of this mixture.
(c) What values are shown by Rohit?

22.

Both Sarika and Mohan were asked to make salt solution. Sarika was given a teaspoonful of salt and half a glass of water whereas, Mohan was given twenty teaspoonful of salt and half a glass of water.
(a) How would they make salt solutions?
(b) Who would be able to prepare saturated solution?

Multiple Choice Question

5 x 1 = 5

23.

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 be 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

24.

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 back solid copper sulphate from the solution?

(a)

Decantation

(b)

Evaporation

(c)

Sedimentation

(d)

Condensation

25.

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)

26.

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

27.

Paheli bought some vegetables such as 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)

Handpicking

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Answers Key:

Generic 3

7 x 3 = 21

Since, sand is heavier while powdered leaves are lighter. When we fall these at the same place, winds separate them as sand is reached at that place vertically and leaves are blown away. This process is known as winnowing.

Threshing is the method of separation based on the fact that the stalk of the crops and the chaff are soft materials, whereas the grains themselves are very hard. Being soft, stalk and chaff can be broken into pieces on beating but the grains remain unaffected.

Winnowing is used to separate grains from impurities like husk by dropping it vertically from a height.
All light impurities are separated by a blowing air or wind and hence, husk from grains are separated easily.

We should add ice to lemonade after dissolving sugar. Without ice, sugar dissolves easily in lemon of juice because solubility depends on the temperature.
When the temperature is high, then more sugar can be dissolved. After mixing ice, it gets cool and less sugar will dissolve in it.

We will separate sand and water from their mixture by the process of sedimentation and decantation.
Sedimentation During this process, we leave mixture for some time, after that the sand which is heavier is settled down at the bottom.
Decantation After the above process, water is poured into another vessel and sand is left in first vessel. Thus, sand and water will be separated from their mixture.

Sieving is a method by which fine particles are separated from bigger particles by using a sieve. It is used in a flour mill, our homes and at construction sites.
In a flour mill, impurities like husk and stones are removed from wheat before grinding. At construction sites, pebbles and stones are removed from sand by sieving.

Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air, e.g. wheat grains and husk are different in weight, husk being lighter than wheat.
When this mixture is allowed to fall down from a height. the wind carries the lighter husk with it and the heavy grains fall vertically down on the ground. This process is used by farmers to separate lighter husk particles from grain.

Fill up / 1 Marks

5 x 1 = 5

()
sieving

()
handpicking

10.

()
filtration

11.

()
decantation

12.

()
threshing

True or False

5 x 1 = 5

13.

(a)
False

14.

(a)
False

15.

(b)
False

16.

(b)
False

17.

(a)
False

Generic 2

3 x 2 = 6

18.

From prepared tea, we separate tea leaves by using a strainer. Tea leaves are bigger in size than the hole of the mesh.

19.

The materials that can be used are a wire-mesh, a piece of cotton, a piece of fine cloth and strainer.

20.

The process of conversion of water vapour into its liquid form is called condensation.

Generic 5

2 x 5 = 10

21.

(a) This is done as follows:
(i) Some water is added to the mixture of sand and salt in a beaker and stirred. Salt dissolves in water to form salt solution, whereas sand remains undissolved. It is then filtered.
(ii) On filtering, sand is obtained as a residue on the filter paper and salt solution is obtained as a filtrate. (iii) The filtrate is evaporated and pure salt is left behind.
(b) The mixture of sand and salt has been separated into its components, i.e sand and salt by doing two methods.
(i) Filtration
(ii) Evaporation
(c) Rohit is knowledgeable and intelligent boy.

22.

(a) They will mix salt with water within a certain amount to make salt solution. Hence, Sarika will make a better salt solution.
(b) Saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amount of that substance will appear as a precipitate, Mohan's solution would be saturated because in Mohan's case, some salt would remain undissolved and settled at the bottom of the glass.

Multiple Choice Question

5 x 1 = 5

23.