📘 Chapter 9: Methods of Separation in Everyday Life

• Answer: (ii) Sorting

• Answer: (iii) Cream from milk

• Answer: (iii) Pore size

• (i) Salt can be separated from salt solution by keeping it under the Sun.
  Answer: [ T ]
  Reason: The heat from the Sun causes the water to evaporate as water vapour, leaving solid salt behind.
• (ii) Handpicking should be used only when the quantity of one component is less.
  Answer: [ T ]
  Reason: Handpicking is convenient when the unwanted particles are present in small quantities and are large enough to be easily picked by hand.
• (iii) A mixture of puffed rice and rice grains can be separated by threshing.
  Answer: [ F ]
  Correct Statement: A mixture of puffed rice and rice grains can be separated by winnowing.
  Reason: Threshing is used to separate grains from harvested stalks. Puffed rice is lighter than rice grains, so wind blowing (winnowing) easily separates them.
• (iv) A mixture of mustard oil and lemon water can be separated by decantation.
  Answer: [ T ]
  Reason: Mustard oil and lemon water do not mix with each other and form two separate layers. The upper layer of oil can be poured off by decantation.
• (v) Sieving is used to separate a mixture of rice flour and water.
  Answer: [ F ]
  Correct Statement: Filtration (or sedimentation and decantation) is used to separate a mixture of rice flour and water.
  Reason: Sieving is used to separate solid-solid mixtures containing particles of different sizes.

Answer (Correct Matching):

• Situation: Decantation is used instead of filtration when the insoluble solid particles in a liquid are relatively heavy, large, and settle down quickly at the bottom of the container (sedimentation).
• Examples: Separating water after washing rice or pulses, or separating coarse sand from water.

• Relation: Yes, the presence of nasal hair is related to the process of filtration.
• Explanation: Nasal hair acts as a natural filter that traps dust particles, dirt, and foreign substances present in the air we inhale, allowing only clean air to pass into our lungs.

• Material: Masks are generally made of cotton cloth, non-woven fabric, or melt-blown polymer layers.
• Role: Masks act as filters (filtration). They filter the air we breathe by blocking virus particles, bacteria, dust, and respiratory droplets from entering our body or spreading into the surroundings.

1. Step 1 - Handpicking: Pick out the large-sized potatoes from the mixture by hand.
2. Step 2 - Adding Water: Add water to the remaining mixture of sawdust and salt and stir well. Salt dissolves in water to form a salt solution, while sawdust floats on top as it is insoluble in water.
3. Step 3 - Filtration: Filter the mixture using a filter paper or fine cloth. The sawdust remains on the filter paper as a residue.
4. Step 4 - Evaporation: Heat the clear salt solution or expose it to sunlight. The water evaporates as water vapour, leaving behind solid salt in the vessel.

• Suggested Title: Leela's Smart Water Purification (or Water Purification by Leela)
• Completed Story 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, 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 boiling, 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.

• Method: Boil tulsi leaves, ginger, and black pepper in water. After boiling, pass the liquid through a strainer.
• Separation Method Used: Filtration.

Mixture: Iron nails, sand, black pepper, stones, common salt, and water.

• Step 1: Use a magnet for magnetic separation to remove iron nails.
• Step 2: Handpick the large stones from the mixture.
• Step 3: Add water and stir well so that common salt dissolves completely.
• Step 4: Skim off floating black pepper using a fine sieve.
• Step 5: Perform filtration using filter paper to separate insoluble sand.
• Step 6: Heat the salt solution to cause evaporation of water, obtaining solid common salt.