Chapter 9: Methods of Separation in Everyday Life
Comprehensive Exercise (Made for exam preparation)
Class 6 Science
Question 1: Choose the correct option (Multiple Choice Questions):
1. Which method is used to separate heavier and lighter components of a mixture using wind or blowing air?
Answer: (B) Winnowing.
2. Which method did the carpenter use to separate iron nails from sawdust?
Answer: (C) Magnetic separation.
3. How are small stones separated from wheat or rice grains before cooking?
Answer: (A) Handpicking.
4. Which process is used to obtain butter from curd or milk?
Answer: (B) Churning.
5. Which process is used to obtain salt from a salt solution?
Answer: (C) Evaporation.
Question 2: Fill in the blanks with the appropriate words:
- 1. The method used to separate unwanted small stones from grains by hand is called handpicking.
- 2. A traditional bamboo tray called a 'soop' is used for the process of winnowing to separate husk from grains.
- 3. A magnet (or electromagnet) attached to a crane is used to separate iron scrap from a large heap of waste materials.
- 4. Heating a salt solution in a china dish leaves the salt behind through the process of evaporation.
- 5. Tea leaves are separated from liquid tea using a strainer or a tea bag, which is an example of filtration.
Question 3: State whether the following statements are True or False:
- 1. Handpicking should be used when the quantity of the mixture is very large.
Answer: False (It is used when the quantity of the mixture is small). - 2. A mixture of oil and water can be separated by the method of decantation.
Answer: True. - 3. A mixture of puffed rice and rice grains can be separated by threshing.
Answer: False (It can be separated by winnowing or handpicking). - 4. Salt can be separated from a salt solution by keeping it under the Sun.
Answer: True. - 5. Sieving is the best method to separate a mixture of rice flour and water.
Answer: False (Filtration is the correct method).
Question 4: Match the items in Column 'A' with their correct method of separation in Column 'B':
| Column 'A' | Column 'B' |
|---|---|
| 1. Gram flour mixed with black gram | (a) Handpicking |
| 2. Chalk powder mixed with water | (b) Magnetic separation |
| 3. Corn mixed with potatoes | (c) Sedimentation & Decantation |
| 4. Iron powder mixed with sawdust | (d) Sieving |
| 5. Muddy water left undisturbed | (e) Filtration |
Correct Matches:
- 1 → (d) Sieving
- 2 → (e) Filtration
- 3 → (a) Handpicking
- 4 → (b) Magnetic separation
- 5 → (c) Sedimentation & Decantation
Question 5: Classification. Classify the following 5 situations into "Can be separated by Handpicking" and "Can be separated by Winnowing":
Items: 1. Small stones in rice, 2. Husk and wheat grains, 3. Green chillies from cooked poha, 4. Peanut skin and roasted peanuts, 5. Rotten fruits from a basket of fresh fruits.
- Handpicking: 1. Small stones in rice, 3. Green chillies from cooked poha, 5. Rotten fruits from a basket of fresh fruits.
- Winnowing: 2. Husk and wheat grains, 4. Peanut skin and roasted peanuts.
Question 6: Answer the following questions in one sentence:
1. Why do we remove small stones from grains before cooking?
Answer: We remove these stones so that the grains are clean, safe, and fit for cooking.
2. What is the traditional bamboo tray used for separating grains from husk called?
Answer: It is called a 'soop'.
3. Name the method used by carpenters to separate accidentally dropped iron nails from sawdust.
Answer: The carpenter uses the method of Magnetic separation.
4. What materials can be used to make a simple water filter at home?
Answer: Materials such as cotton, charcoal, sand, and filter paper can be used to make a water filter.
5. Why are medicinal herbs dried in the shade according to Ayurveda?
Answer: This practice facilitates the evaporation of excess water, leaving behind the important part of the medicine.
Question 7: Give scientific reasons:
1. Reason: We use electromagnets in recycling industries or scrap yards.
Answer: Because waste often contains scrap iron, and a magnet easily attracts and separates the iron articles from the heap for recycling.
2. Reason: A farmer stands on a raised platform while doing winnowing.
Answer: By dropping the mixture from a height in the direction of the wind, the lighter husk is blown away to a distance, while the heavier wheat grains fall straight down, separating the two easily.
3. Reason: We blow air over roasted peanuts after rubbing them between our palms.
Answer: Because blowing air acts like winnowing, which separates and blows away the lighter peanut skin from the heavier peanuts.
4. Reason: Early tea bags were made of soft cloth like silk.
Answer: Because silk was strong, did not fall apart in hot water, and acted as a good filter that held the tea leaves but let the liquid pass through.
5. Reason: When muddy pond water is kept undisturbed in a container, the mud settles down.
Answer: Because the insoluble mud particles are heavier than water, they settle down at the bottom due to gravity. This process is called sedimentation.
Question 8: Answer the following questions in short (2-3 sentences):
1. Explain the process of 'Winnowing' with an example.
Answer: Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. For example, farmers separate the lighter husk from heavier wheat grains by dropping the mixture from a raised platform in the direction of the wind.
2. How can you separate a mixture of iron nails and sawdust?
Answer: We can separate them using the method of magnetic separation. When a magnet is moved through the mixture, the iron nails get attracted and stick to the magnet, leaving the sawdust behind.
3. What is evaporation? Give one practical application of it.
Answer: Evaporation is the process of converting a liquid into a gas (vapour) by heating. It is practically used to obtain salt from a salt solution or to dry leaves and seeds in Ayurveda.
4. Suggest a step-wise method to purify muddy water for drinking, as done by 'Leela' in the chapter.
Answer: First, keep the muddy water undisturbed so the mud settles down (Sedimentation). Then, carefully pour out the clear water (Decantation) or filter it using a muslin cloth (Filtration). Finally, boil and cool the water to make it safe for drinking.
5. Why is it important to learn different methods of separation?
Answer: Learning separation methods helps us in our daily lives to remove unwanted or harmful substances (like stones from rice), to obtain useful components (like butter from curd), and to purify things (like water).