Class 6 Science – Chapter 5

Separation of Substances | NCERT Complete Notes

STAGE 0: Foundation / Basics

What is this Chapter About?

This chapter explains why and how we separate substances in daily life. It introduces simple methods like handpicking, winnowing, sieving, sedimentation, filtration, and evaporation.

Why Should We Learn This Chapter?

• To remove unwanted substances from useful materials
• To make food clean and usable
• To understand basic separation methods used at home

Basic Meaning

Separation: The process of removing unwanted substances from useful ones.

STAGE 1: Complete Chapter Explanation

Why Do We Separate Substances?

• To remove impurities
• To get pure substances
• To separate useful components

Methods of Separation

1. Handpicking

Large impurities like stones are removed by hand.
Example: Removing stones from rice.

2. Winnowing

Lighter particles are separated from heavier ones using wind.
Example: Separating husk from grains.

3. Sieving

Fine particles are separated from coarse particles using a sieve.
Example: Sieving flour.

4. Sedimentation and Decantation

Heavy insoluble substances settle at the bottom (sedimentation). The clear liquid is then poured out (decantation).
Example: Muddy water.

5. Filtration

Insoluble solids are separated using a filter.
Example: Filtering tea leaves.

6. Evaporation

Water is removed by heating, leaving the solid behind.
Example: Getting salt from seawater.

Soluble and Insoluble Substances

• Soluble: Substances that dissolve in water (salt, sugar)
• Insoluble: Substances that do not dissolve (sand, chalk)

STAGE 2: NCERT Textbook Questions & Answers

Q1. Why do we need to separate substances?
Answer: To remove impurities and obtain useful substances.

Q2. What is winnowing?
Answer: Winnowing is a method used to separate lighter impurities from heavier grains using wind.

Q3. Name the method used to separate sand and water.
Answer: Sedimentation and decantation or filtration.

Q4. How is salt obtained from seawater?
Answer: Salt is obtained by evaporation of seawater.

STAGE 3: Previous Exam Questions & Answers

Previous Exam Question:
Explain any two methods of separation with examples.

Answer:
Handpicking: Stones are removed from rice by hand.
Filtration: Tea leaves are separated from tea using a strainer.

Exam Insight:
Questions on daily life separation methods are very common in Class 6 exams.

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📘 Class 6 Science – Chapter Series
1. Food – Where Does It Come From?
2. Components of Food
3. Fibre to Fabric
4. Sorting Materials into Groups
5. Separation of Substances
6. Changes Around Us (Next)