NCERT Class 6 Science Chapter 5 separation methods notes.

Chapter 5: Separation of substances

These NCERT Class 6 Science Chapter 5 notes explain why separation of substances is needed in daily life. The chapter introduces students to the concept of mixtures and shows how different components of a mixture can be separated using simple methods.

NCERT Class 6 Science Chapter 5 – Separation of Substances helps students understand common household and agricultural practices such as handpicking, threshing, winnowing, sieving, filtration, and evaporation. These methods are widely used in India in homes and farms.

This chapter develops basic understanding of cleaning food, obtaining useful substances, and purifying water, which are essential life skills.

1. Why is separation needed?

  • In daily life, many substances are mixed together
  • Separation helps to remove impurities from substances
  • Separation helps to obtain useful substances
  • Separation makes food safe and clean
  • Separation helps in proper use of materials

2. Types of mixtures

  • A mixture is a combination of two or more substances
  • The substances in a mixture are not chemically combined
  • Sand and water form a mixture
  • Rice and stones form a mixture
  • Salt in water is also a mixture

3. Methods of separation

  • Different mixtures need different separation methods
  • The method depends on the nature of substances
  • Size, weight, and solubility decide the method
  • Separation methods are used in homes and farms
  • These methods make work easy and efficient

4. Handpicking

  • Handpicking is used when impurities are large and visible
  • It is done by hand
  • Stones are removed from pulses and rice
  • Rotten fruits are separated from good fruits
  • It is a simple and common method

5. Threshing

  • Threshing is used to separate grain from stalk
  • It is done by beating the harvested crop
  • Threshing can also be done using machines
  • It is commonly used in Indian agriculture
  • It helps farmers collect grains

6. Winnowing

  • Winnowing is used to separate husk from grain
  • It is based on wind or air flow
  • Lighter husk is blown away by wind
  • Heavier grains fall down
  • Farmers commonly use this method

7. Sieving

  • Sieving is used to separate particles of different sizes
  • A sieve has small holes
  • Fine particles pass through the sieve
  • Bigger particles remain on the sieve
  • Bran is removed from flour using sieving

8. Sedimentation and decantation

  • This method is used when insoluble solid is mixed with liquid
  • In sedimentation, heavy particles settle at the bottom
  • The solid settles due to gravity
  • In decantation, clear liquid is carefully poured out
  • Used in cleaning muddy water

9. Filtration

  • Filtration separates insoluble solids from liquids
  • A filter allows liquid to pass through
  • Solid particles remain on the filter
  • Filtering tea is a common example
  • Used in water purification

10. Evaporation and condensation

  • Evaporation is used to obtain dissolved solids
  • Water changes into vapour during evaporation
  • Salt is obtained from seawater by evaporation
  • Condensation is cooling vapour to get liquid
  • Condensation is the opposite of evaporation

11. Solution

  • A solution is formed when a substance dissolves completely
  • The dissolved substance is called solute
  • The liquid in which it dissolves is called solvent
  • Salt in water is a solution
  • Solutions look uniform

12. Saturated and unsaturated solutions

  • A saturated solution cannot dissolve more solute
  • It already contains the maximum amount of solute
  • An unsaturated solution can dissolve more solute
  • Temperature affects solubility
  • These terms help in understanding solutions

13. Loading

  • Loading is used to speed up sedimentation
  • A chemical like alum is added to muddy water
  • Alum makes small particles heavier
  • Heavy particles settle faster
  • Used in water purification

14. Importance of this chapter

  • Explains household practices clearly
  • Helps understand agricultural methods
  • Builds foundation for chemistry
  • Important for understanding water purification
  • Very useful for daily life science

15. Important keywords and definitions

  • Mixture: Combination of two or more substances
  • Handpicking: Separation of large impurities by hand
  • Threshing: Separation of grain from stalk
  • Winnowing: Separation of husk from grain using wind
  • Sieving: Separation based on particle size
  • Filtration: Separation of insoluble solid from liquid
  • Evaporation: Change of liquid into vapour
  • Sedimentation: Settling of heavy particles at the bottom
  • Decantation: Pouring out clear liquid after sedimentation
  • Solution: A mixture in which a substance dissolves completely

Understanding NCERT Class 6 Science Chapter 5 is important to learn how impurities are removed and useful materials are obtained from mixtures. The chapter connects science concepts with daily life activities like cooking and farming.

The ideas discussed in Separation of Substances form the foundation for future topics in chemistry and water purification.
Continue reading NCERT Class 6 Science Chapter 6 – Changes Around Us to understand different types of changes in materials.

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FAQs

Q1. What is a mixture according to NCERT Class 6 Science Chapter 5?
A mixture is a combination of two or more substances mixed together.

Q2. Why is separation of substances needed?
Separation helps remove impurities and obtain useful substances.

Q3. What is winnowing?
Winnowing is the method of separating husk from grain using wind.

Q4. What is evaporation used for?
Evaporation is used to obtain dissolved solids like salt from seawater.

Q5. Why is this chapter important for exams?
It explains basic separation techniques used in daily life, useful for school exams and BPSC foundation.

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