CBSE Class 6 Science Exemplar Chapter 4: Sorting Materials and Groups NCERT Solutions

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CBSE Class 6 Science Exemplar Chapter 4, 'Sorting Materials into Groups,' introduces students to the fascinating world of materials and their properties. This chapter helps us understand how different substances can be categorized based on characteristics like transparency, translucency, and opacity, which describe how light passes through them. We also explore solubility, learning which materials dissolve in water and which do not. The solutions guide us through identifying materials that float or sink, a concept often illustrated with everyday examples like safety pins. By breaking down these concepts with clear explanations and step-by-step problem-solving, these NCERT Solutions aim to build a strong foundation in material science and prepare students effectively for their exams. This approach makes learning about the properties and classification of materials an engaging and accessible experience.

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Quick info

BoardCBSE
ClassClass 6
SubjectScience Exemplar
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 4

Chapter summary

Chapter 4 of the CBSE Class 6 Science Exemplar, 'Sorting Materials and Groups,' introduces fundamental concepts of material science. The NCERT Solutions cover exercises on classifying materials based on their properties like transparency (transparent, translucent, opaque), solubility in water, and whether they float or sink. It also touches upon the uses of materials in everyday objects. These solutions aim to build a strong foundation for understanding the physical characteristics of matter.

Learning outcomes

  • Understand the concepts of transparent, translucent, and opaque materials.
  • Identify materials based on their solubility in water.
  • Determine whether a material will float or sink in water.
  • Classify materials based on their physical properties.
  • Relate material properties to their common uses.

Topics covered

Paper topics

  • Sorting Materials
  • Properties of Materials
  • Transparency
  • Translucency
  • Opacity
  • Solubility in Water
  • Buoyancy (Floating and Sinking)
  • Classification of Materials
  • Material Properties and Uses

Important topics

  • Transparent, Translucent, and Opaque Materials
  • Solubility of Substances in Water
  • Objects that Float and Sink
  • Classifying Materials based on Properties

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Questions and Solutions

Multiple Choice Questions: 1

An iron nail is kept in each of the following liquids. In which case would it lose its shine and appear dull?
  1. Mustard oil
  2. Soft drink
  3. Coconut oil
  4. Kerosene
Solution: (b): Soft drink

When an iron nail is placed in a soft drink, it loses its shine and appears dull. This happens because soft drinks contain water, carbon dioxide, and acids. These substances react with the iron, causing it to corrode. This process is known as rusting or corrosion, which makes the iron surface appear dull and discolored.

Multiple Choice Questions: 2

Pick one material from the following which is completely soluble in water.
  1. Chalk powder
  2. Tea leaves
  3. Glucose
  4. Sawdust
Solution: (c): Glucose

Glucose is a substance that dissolves completely in water. When glucose is added to water and stirred, it forms a clear solution because the glucose particles disperse evenly throughout the water. Chalk powder, tea leaves, and sawdust do not dissolve completely in water; they either remain suspended or settle down at the bottom.

Multiple Choice Questions: 3

You are provided with the following materials:
  1. Magnifying glass
  2. Mirror
  3. Stainless steel plate
  4. Glass tumbler
Which of the above materials will you identify as transparent?
  1. (i) and (ii)
  2. (i) and (iii)
  3. (i) and (iv)
  4. (iii) and (iv)
Solution: (c): Magnifying glass and glass tumbler

Transparent materials are those through which light can pass easily, allowing us to see objects clearly on the other side. Both a magnifying glass and a glass tumbler are made of materials (like glass) that are transparent. A mirror is opaque, and a stainless steel plate is also opaque, as they do not allow light to pass through them.

Multiple Choice Questions: 4

Boojho found a bag containing the following materials:
  1. Mirror
  2. Paper stained with oil
  3. Magnet
  4. Glass spectacles
Help Boojho in finding out the material(s) which is/are opaque.
  1. (i) only
  2. (iv) only
  3. (i) and (iii)
  4. (ii) and (iv)
Solution: (c): Mirror and Magnet

Opaque materials are those that do not allow light to pass through them. A mirror is opaque because it reflects light. A magnet, typically made of metal, is also opaque. Paper stained with oil is translucent, meaning some light can pass through, but not clearly. Glass spectacles are transparent, allowing clear passage of light.

Multiple Choice Questions: 5

While doing an activity in class, the teacher asked Paheli to handover a translucent material. Which among the following materials will Paheli pick and give her teacher?
  1. Glass tumbler
  2. Mirror
  3. Muslin cloth
  4. Aluminium foil
Solution: (c): Muslin cloth

A translucent material allows some light to pass through it, but it scatters the light, so objects behind it cannot be seen clearly. Muslin cloth fits this description. A glass tumbler is transparent. A mirror and an aluminium foil are opaque, blocking light completely.

Multiple Choice Questions: 6

Which pair of substances among the following would float in a tumbler half filled with water?
  1. Cotton thread, thermocol
  2. Feather, plastic ball
  3. Pin, oil drops
  4. Rubber band, coin
Solution: (b): Feather, plastic ball

Objects float in water if their density is less than the density of water. Feathers and plastic balls are generally very light for their size, meaning they are less dense than water. Therefore, they will float. Cotton thread might float or sink depending on its density and how it absorbs water. Pins, oil drops (initially), rubber bands, and coins are denser than water and will sink.

Multiple Choice Questions: 7

Which among the following are commonly used for making a safety pin?
  1. Wood and glass
  2. Plastic and glass
  3. Leather and plastic
  4. Plastic and metal
Solution: (d): Plastic and metal

Safety pins are typically made from metal, such as steel, because metal is strong, durable, and can be shaped into the required form. Sometimes, plastic components might be used for decorative or functional purposes, but the primary material for the pin itself is metal. Wood, glass, and leather are not suitable materials for making functional safety pins due to their properties (brittleness, lack of strength, or flexibility).

Common mistakes

  • Confusing translucent and transparent materials.
  • Incorrectly identifying materials that are soluble or insoluble in water.
  • Assuming all materials of a certain type (e.g., plastic) have the same buoyancy.
  • Not considering all properties when classifying materials.

Revision tips

  • Review the definitions of transparent, translucent, and opaque with examples.
  • Create a table to list materials and their solubility in water.
  • Practice predicting whether objects will float or sink based on their material.
  • Use the provided solutions to understand the reasoning behind each classification.

Practice MCQs

Q1. Which of the following liquids is most likely to cause an iron nail to lose its shine and appear dull due to corrosion?

Q2. Which of these materials is completely soluble in water?

Q3. Which of the following pairs of materials are transparent?

Q4. Identify the opaque materials from the given list: Mirror, Paper stained with oil, Magnet, Glass spectacles.

Q5. Which material is translucent, allowing light to pass through but not clearly?

Q6. Which pair of objects is most likely to float in water?

Frequently asked questions

What is the main topic of Chapter 4 for Class 6 Science Exemplar?

Chapter 4 focuses on 'Sorting Materials and Groups,' teaching students how to classify different materials based on their observable properties like appearance, hardness, solubility, and transparency.

What does it mean for a material to be transparent?

A transparent material allows light to pass through it completely, so you can see objects clearly on the other side. Examples include glass tumblers and magnifying glasses.

How can I determine if a material is opaque?

An opaque material does not allow any light to pass through it. You cannot see through an opaque object. Examples include mirrors and magnets.

What is the difference between soluble and insoluble materials in water?

Soluble materials dissolve completely in water, like glucose. Insoluble materials do not dissolve, such as chalk powder or sawdust.

Why do some objects float in water while others sink?

Objects float if they are less dense than water (lighter for their size), like feathers and plastic balls. Objects sink if they are denser than water (heavier for their size), like pins and coins.

How do these NCERT Solutions help with exam preparation?

These solutions provide clear, step-by-step explanations for each question, reinforcing understanding of material properties and classification, which is crucial for answering exam questions accurately.

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