CHAPTER 3
Practice Set 4
Let’s Separate the Components
Grade 6 Science • Maharashtra State Board • 30 Marks
Q.1 (A) Choose the correct option.
4 Marks
(1) Which method is used when two solid substances have particles of different sizes?
(2) Which liquid forms the lower layer in a mixture of oil and water?
(3) What is left behind after the evaporation of a salt solution?
(4) The filtering curtain made from crop-straw ash is used to clean __________.
Q.1 (B) Identify me.
4 Marks
(1) I am a method in which the liquid above settled particles is slowly poured into another vessel. Who am I?
(2) I contain extremely microscopic pores and am used in a laboratory. Who am I?
(3) I am light, fatty and float on buttermilk after curd is churned. Who am I?
(4) I attract substances such as iron, cobalt and nickel. Who am I?
Q.2 Rewrite the incorrect scientific term.
3 Marks
(1) The process of slowly pouring the clear water above settled soil is called sedimentation.
(2) Separating heavy grains from light chaff with the help of wind is called filtration.
(3) The conversion of a liquid into a gaseous state due to heat is called churning.
Q.3 Arrange the steps in the correct sequence.
4 Marks
(1) Write the correct sequence for obtaining clear water from muddy water:
Pour the clear water into another vessel
•
Leave the muddy water undisturbed
•
Soil settles at the bottom
(2) Write the correct sequence for obtaining salt from seawater:
Salt remains behind
•
Collect seawater in salt pans
•
Water evaporates in sunlight
Q.4 Complete the table.
4 Marks
| Method | Property or Condition Used | One Example |
|---|---|---|
| Handpicking | ________________ | Removing chillies from vegetables |
| Winnowing | Difference in weight | ________________ |
| Filtration | Insoluble solid mixed with a liquid | ________________ |
| Magnetic separation | ________________ | Removing magnetic materials from city waste |
Q.5 Answer the following.
5 Marks
(1) Why are different sieves required for cleaning grains and separating bran from flour?
(2) Why is handpicking unsuitable when unwanted components are present in a large quantity?
(3) How are modern rapidly rotating machines useful in dairies and blood banks?
Q.6 Read the passage and answer.
4 Marks
During an epidemic, people travelling in crowded vehicles and visiting hospitals are advised to cover their nose and mouth with a mask.
(1) Which separation method works on a similar principle?
(2) What does the mask prevent from entering the nose and mouth?
After harvesting, leftover crop straw is sometimes burnt. Scientists used its ash to create a curtain containing very tiny pores.
(3) What is this curtain used for?
(4) Why can this curtain work like a filter?
Q.7 Give scientific reasons.
3 Marks
(1) A strainer with a very fine mesh is needed to separate an insoluble solid from a liquid.
(2) A strong airflow created by a large fan reduces the time needed for winnowing.
(3) Magnetic materials should be separated from garbage collected in large quantities.
Q.8 Answer in one sentence.
3 Marks
(1) What is separation?
(2) What are methods of separation?
(3) Name the source of energy used for obtaining salt from seawater.
CHAPTER 3
Practice Set 4 – Solutions
Let’s Separate the Components
Q.1 (A) Choose the correct option.
(1) Method for solids having particles of different sizes
Answer: (b) Sieving
(2) Lower layer in an oil-and-water mixture
Answer: (b) Water
(3) Substance left after evaporating salt solution
Answer: (a) Solid salt
(4) Use of the filtering curtain
Answer: (c) Industrial wastewater
Q.1 (B) Identify me.
(1) Slowly pouring liquid above settled particles
Answer: Decantation
(2) Laboratory material with microscopic pores
Answer: Filter paper
(3) Fatty and light substance floating on buttermilk
Answer: Butter
(4) Object that attracts iron, cobalt and nickel
Answer: Magnet
Q.2 Rewrite the incorrect scientific term.
(1) Slowly pouring clear water above settled soil
Correct term: Decantation
(2) Separating heavy grains from light chaff with wind
Correct term: Winnowing
(3) Conversion of a liquid into gas due to heat
Correct term: Evaporation
Q.3 Arrange the steps in the correct sequence.
(1) Obtaining clear water from muddy water
Leave muddy water undisturbed
→
Soil settles at the bottom
→
Pour clear water into another vessel
(2) Obtaining salt from seawater
Collect seawater in salt pans
→
Water evaporates in sunlight
→
Salt remains behind
Q.4 Complete the table.
| Method | Property or Condition Used | One Example |
|---|---|---|
| Handpicking | Difference in shape and colour | Removing chillies from vegetables |
| Winnowing | Difference in weight with the help of wind | Separating chaff from grains |
| Filtration | Insoluble solid mixed with a liquid | Separating tea powder from tea |
| Magnetic separation | Magnetic property | Removing magnetic materials from city waste |
Q.5 Answer the following.
(1) Why are different sieves required for grains and flour?
Answer: The particles to be separated are of different sizes. A suitable sieve is used to remove stones from grains, while a sieve with a finer mesh is required to separate coarse bran from fine flour.
(2) Why is handpicking unsuitable for a large quantity of unwanted components?
Answer: Handpicking requires every unwanted component to be observed and removed by hand. Therefore, it is convenient only when the unwanted components are few in number.
(3) How are rapidly rotating machines useful in dairies and blood banks?
Answer: In large dairies, rapidly rotating machines separate cream from milk. In blood banks, such machines are used to separate the different components of blood.
Q.6 Read the passage and answer.
(1) Which method works on a principle similar to a mask?
Answer: Filtration.
(2) What does a mask prevent from entering the nose and mouth?
Answer: Its fine pores help block tiny harmful particles and droplets present in the air.
(3) What is the curtain made from crop-straw ash used for?
Answer: It is used to clean industrial wastewater.
(4) Why can this curtain work like a filter?
Answer: The curtain contains very tiny pores that allow liquid to pass while holding back unwanted particles.
Q.7 Give scientific reasons.
(1) A fine mesh is needed to separate an insoluble solid from a liquid.
Answer: A fine mesh has very small holes. The liquid passes through them, while the larger insoluble solid particles remain on the mesh.
(2) A large fan reduces the time required for winnowing.
Answer: A large fan creates a strong flow of air. It carries away the lighter chaff quickly while the heavier grains fall straight down.
(3) Magnetic materials should be separated from garbage.
Answer: Magnetic materials such as iron, cobalt and nickel are used to manufacture many items. Separating them from garbage makes their collection and reuse possible.
Q.8 Answer in one sentence.
(1) What is separation?
Answer: Separating mixed substances from a mixture is called separation.
(2) What are methods of separation?
Answer: Methods that use differences in the properties of mixed substances to separate them are called methods of separation.
(3) Name the source of energy used for obtaining salt from seawater.
Answer: Solar energy.