NCERT Class 6 Science Chapter 2 ‘Sorting Materials into Groups’: Notes and Solutions (Free PDF)

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Class 6 Chapter 2 Science

NCERT Solutions and Notes for Class 6 Science Chapter 2: Sorting Materials into Groups help in understanding thoroughly the basic concepts of material qualifications. The notes on “Sorting of Materials” explain how to classify materials and types of materials. In addition, this CBSE Class 6 Science chapter notes explain buoyancy, density, toughness, and metal polishing. Also, you will learn about examples of different materials. Also, we have included all important questions in this textbook. Further, to help you prepare for your examination, we have provided answers to all questions. 

Explore all the Chapters of Class 6 Science:-

Chapter 1: Components of FoodChapter 3: Separation of SubstancesChapter 4: Getting to Know PlantsChapter 5: Body MovementsChapter 6: The Living Organisms — Characteristics and Habitats
Chapter 7: Motion and Measurement of DistancesChapter 8: Light, Shadows and ReflectionsChapter 9: Electricity and CircuitsChapter 10: Fun with MagnetsChapter 11: Air Around Us

Summary of NCERT Class 6 Science Chapter 2

Let us begin our learning or revision with a summary of NCERT Class 6 Science Chapter 2. As per this chapter we are surrounded by a huge range of things and every object in our environment is made of one or more materials. It also explains that different materials can be used to create a thing. Additionally, we also learn that the same material can be used to create numerous objects.

Also Read: NCERT Class 6 Science Chapter 1 Components of Food Notes

Sorting Materials into Groups Notes

Let us now explore the notes of sorting materials into groups and all the related topics!

How to Categorise/Group Materials?

Based on individual properties, materials can be classified into different groups. Here are some scientific ways to classify common materials around us:

  • Firstly, materials can be categorised into 3 States of Matter: Solid, Liquid, and Gas
  • Secondly, materials can be sorted on the basis of their Appearance: Colour, Texture, Toughness, and Lusture
  • Thirdly, materials can be grouped on the basis of Solubility: Soluble in Water and Insoluble in Water
  • In addition, Science classifies materials as Metals and Non-Metals
  • Finally,  materials can also be graded on the basis of Light Transmission through Objects: Transparent, Translucent, Opaque

Classification of Materials on Appearance

On the basis of appearance, materials are grouped into Lustrous and Non-Lustrous. Shiny items are known as lustrous materials and dull objects are termed non-lustrous materials. 

Here are some examples of different types of substances based on their look:

  • Lustrous Materials: Gold, Aluminium, Diamond, Iron
  • Non-Lustrous Materials: Wood, Chalk, Sand, Paper

Also Read: Who Discovered Electron?

Classification of Materials on Toughness

Based on toughness, objects can be sorted into hard and soft materials. Any substance that cannot be or is difficult to compress or bend is known as hard material. Whereas, a material that is easily deformed or compressed is called a soft substance. 

Here are some common hard and soft materials:

  • Hard Materials:  Iron, Gold, and Diamond
  • Soft Materials: Sponge, Cotton, and Wax

Classification of Materials on Solubility

Substances that dissolve in water are called Soluble materials. On the other hand, substances that do not disappear in water are known as Insoluble materials.

Here are some examples of soluble and insoluble substances:

  • Soluble Materials: Salt, Sugar, Coffee, Vinegar, and Lime Juice
  • Insoluble Materials: Sawdust, Sand, Mustard Oil, Coconut Oil, and Chalk Powder

Classification of Materials on Buoyancy

Based on buoyancy, substances either float on water or sink in water. Objects that cannot exceed buoyancy and have lighter density can float. Whereas, those exceeding buoyancy and having higher densities can sink in water.

Here are some examples of materials that float and those that sink:

  • Floating Objects: Leaf, Paper, Cork, Feather, and Piece of Thermocol
  • Sinking Objects: Wood log, Iron slab, Metal spoon, Wooden boat, and Asbestos sheet

Also Read: What is a Food Web?

Classification of Materials on Transparency

Based on their ability to transmit visible light, substances can be sorted into Transparent, Opaque, and Translucent. Any material that enables light to pass through is known as transparent. Whereas, an opaque object obstructs visible light. On the other hand, a substance that allows light to pass partially through is known as a translucent object. 

Here are examples of objects based on transparency:

  • Transparent Objects: Fish tank, Glassdoor
  • Translucent Objects: Paper cup, Plastic bottle
  • Opaque Objects: Metals, Wood

Also Read: All You Need to Know About Science Stream Subjects

Source: Magnet Brains

Important Definitions in NCERT Class 6 Chapter 2


The term “buoyancy” refers to the upward push a liquid applies to an object submerged in it. An upward force is imposed on an object when you try to submerge it in water, and this force grows as the thing is pushed deeper.


Density means “mass per volume.” Consider it as how many particles of a substance are stuffed into a given volume of space. The density would be higher if the particles were packed closely together than if they were spread out widely and loosely packed. This is regarded as the object’s mass in relation to its volume. The SI unit of density is kg/m3.

Metal Polishing

It is a technique for increasing the toughness and roughness of metal surfaces. As it prevents oxidation, metal polishing protects against metal surfaces.


Toughness is the ability of a material to withstand force without breaking. In comparison to a material with low strength and high ductility, a material with high strength and high ductility will be more tough.

Explore all the Chapters of Class 6 Science:-

Chapter 1: Components of FoodChapter 3: Separation of SubstancesChapter 4: Getting to Know PlantsChapter 5: Body MovementsChapter 6: The Living Organisms — Characteristics and Habitats
Chapter 7: Motion and Measurement of DistancesChapter 8: Light, Shadows and ReflectionsChapter 9: Electricity and CircuitsChapter 10: Fun with MagnetsChapter 11: Air Around Us

Important Questions and Answers in CBSE Class 6 Chapter 2

Here are the answers to all the questions included in NCERT Class 6 Chapter 2 Exercises.

Ques 1: Name 6 objects that can be made from wood.

Ans: Chair, table, bed, boat, and cricket bat

Ques 2: Which of the following objects shine:

  1. Plastic toy
  2. Cotton shirt
  3. Glass bowl
  4. Steel spoon

Ans: Glass bowl and Steel spoon

Ques 3: Match the following


Ans: Tumbler-Glass





Ques 4: Which of the following statements are True or False

  1. Chalk can be dissolved in water
  2. Glass is opaque, whereas stone is transparent
  3. A small piece of wood can float on water
  4. An eraser does not have lustre, whereas a notebook has lustre
  5. Sugar is insoluble in water
  6. Oil mixes with water
  7. Vinegar is soluble in water
  8. Sand settles at the bottom of the water

Ans: a.False








Ques 5: Here are some objects and materials:

             Earthen pitcher, water, globe, basketball, sugar, apple, and orange.

            Group these as:

  1. Eatables and non-eatables
  2. Round shape and other shapes


EatablesApple, Orange, Sugar, Water
Non-eatablesEarthern pitcher, basketball, globe
Round ShapeGlobe, basketball, earthen pitcher, orange
Other ShapesApple, sugar, water

Ques6: Name 5 items that float on water. 

Ans: Paper, a piece of wood, straw, feathers, and oil float on water.

Ques 7: Find the odd one out from the following:

  1. Aluminium, Sand, Copper, Iron, Silver
  2. Cupboard, Chair, Baby, Table, Bed
  3. Copper Sulphate, Salt, sand, Sugar 
  4. Boat, Rose, Lotus, Jasmine, Marigold

Ans: a. Sand

         b. Baby

         c. Sand

         d. Boat

Download NCERT Science Class 6 Science Chapter 1 Important Questions and Answers PDF

Explore Notes of All subjects of CBSE Class 6:-

CBSE NCERT Notes Class 6 EnglishCBSE NCERT Notes Class 6 History CBSE NCERT Notes Class 6 Geography
CBSE  NCERTNotes Class 6 CivicsCBSE NCERT Notes Class 6 Mathematics


Q.1. What is buoyancy?

Ans: It is the upward force that the fluid exerts on an object or body when it is placed in or submerged in the fluid.

Q.2. Name some opaque objects.

Ans: Gold, silver, wood, bone china, and bricks are examples of opaque objects.

Q.3. What is the SI unit of Density?

Ans: The SI unit of density is kg/m3.

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