CHAPTER- 9 METHODS OF SEPARATION IN EVERYDAY LIFE
NOTES
1. Mixture– A substance in which two or more substances are mixed together is called a mixture. Example: wheat and rice.- The process of separating small stones and husk from a solid mixture by hand is called handpicking.
2. Threshing– The process of separating grains is called threshing. Example, separating wheat grains.
3. Traditionally, a soop (a container made of bamboo) is used to separate the heavy and light components of a mixture.
4. Winnowing– The method of separating the heavy and light components of a mixture by using air or blowing is called winnowing.
5. When the components of a mixture of two or more solids have different particle sizes, the sieving method is used.
6. Salt-
- To obtain salt, seawater is kept in shallow pits where it is exposed to sunlight and air.
- In a few days, the water completely evaporates and solid salt remains.
- Then this mixture of salts is purified to obtain common salt.
7. Sedimentation– In a mixture of a solid and a liquid, the heavier component settles down at the bottom. This process is called sedimentation.
8. Decantation– When the vessel is tilted to remove the water, this process is called decantation.
9. Filtration– The process of separating tea leaves from tea is called filtration (filtering).
- If water is still dirty even after filtering once, the impurities can be separated using filter paper, which has even smaller pores or holes. Filter paper is a type of filter that has extremely fine pores.
10. Churning– The process of obtaining butter by churning curd is called churning. In this process, because butter is lighter, it floats on the top while buttermilk remains below.
11. Magnetic separation– Substances that are attracted towards a magnet are called magnetic substances.
- The process of separating magnetic and non-magnetic substances using a magnet is called magnetic separation.
LET US ENHANCE OUR LEARNING
Question- 1. What purpose does handpicking serve in the process of separation?
(1) Filtration, (2) Sorting, (3) Evaporation, (4) Decantation
Answer- (2) Sorting
Question- 2. Which of the following substances are commonly separated using the churning method?
(1) Oil from water, (2) Sand from water, (3) Cream for milk, (4) Oxygen from air
Answer- (3) Cream for milk
Question- 3. Which factors is usually essential for the filtration?
(1) Apparatus size, (2) Presence of air, (3) Pore size, (4) Temperature of the mixture
Answer- (3) Pore size
Question- 4. State with reason(s) whether the following statements are True (T) or False (F). Also, correct the false statement (s).
(1) Salt can be separated from salt solution by keeping it under the sun. ( )
(2) Handpicking should be used only when the quantity of one component is less. ( )
(3) A mixture of puffed rice and rice grains can be separated by threshing. ( )
(4) A mixture of mustard oil and lemon water can be separated by decantation. ( )
(5) Sieving is used to separate a mixture of rice flour and water. ( )
Answer- (a) Salt can be separated from its solution by keeping it in sunlight or under the sun. (✓)
Because when kept in sunlight, the water evaporates, leaving the salt behind.
(b) Handpicking is used only when one component is in a small quantity. (×)
Because the handpicking method is used for mixtures where the particles differ in size, color, or shape, and can be easily separated by hand.
(c) A mixture of puffed rice and rice grains can be separated by threshing. (×)
Because a mixture of puffed rice and rice grains cannot be separated by threshing; the winnowing method is used for this.
(d) A mixture of mustard oil and lemon juice can be separated by decantation. (×)
Because a mixture of mustard oil and lemon juice cannot be separated by decantation; it can be separated using a funnel or some other method since they are of different types.
(e) Filtration is used to separate rice flour from water. (✓)
Because the filtration method is used to separate a solid from a liquid.
Question- 5. Match the mixtures in Column 1 with their method of separation in Column 2.
Question- 6. In what situations would you use decantation instead of filtration to separate solids from liquids?
Answer- The decantation method is used when a solid substance is not dissolved in a liquid and settles at the bottom of the liquid. For example, if there is a mixture of soil and water, the soil settles at the bottom of the water, which can be separated by decantation. If the solid is light and floats in the liquid, the filtration method is used.
Question- 7. Can you relate the presence of nasal hair to any separation process?
Answer- The presence of hairs in the nose can be compared to the filtration process. The hairs in the nose prevent dust particles and other impurities present in the air from entering the nasal cavity, just as in the filtration process, solid particles are separated from a liquid through pores.
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- During COVID-19, the masks we all wore were generally made of cotton or polyester. The role of the mask is to prevent viruses, bacteria, dust, and other harmful particles present in the air from entering the body through the nose and mouth. This mask works like the filtration process, stopping external harmful substances from entering the body.
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- First step – Handpicking: First, separate the potatoes from the mixture using the handpicking method. The large size of the potatoes makes them easy to pick out.
Second step – Decantation: After handpicking, put the remaining mixture into water. Sawdust is light and will float on the surface of the water, while salt will dissolve in the water. Remove the sawdust from the surface of the water.
Third step – Evaporation: After using the decantation method, separate the salt from the salt solution by using the evaporation method. Boil the water to evaporate it, so that the salt remains at the bottom of the container. In this way, you can also separate 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.
Leela was working in the form 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/boiled 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.
Answer- 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.
Another suitable title: “Wise Leela”
