Chapter 2: Sorting Materials into Groups (6th Standard CBSE)

1. Objects and Materials:

Introduction to Materials:
- Everything around us is made from various materials. These materials include wood, plastic, metal, glass, cotton, paper, and many more.
- Different objects are made from these materials depending on their properties and uses. For example, chairs can be made of wood or plastic, and utensils can be made of metal or glass.
Examples of Materials:
- Common materials and their uses:
  - Wood: Used to make furniture (chairs, tables), tools (handles, spoons), and structures (doors, windows).
  - Plastic: Used to make containers (bottles, boxes), toys, and everyday household items (buckets, cups).
  - Metal: Used to make tools (hammers, screwdrivers), machinery, utensils, and structural components (beams, rods).
  - Glass: Used to make windows, containers (jars, bottles), and decorative items (vases, ornaments).
  - Cotton: Used to make clothing, bedding, and other textiles.
  - Paper: Used to make books, notebooks, newspapers, and packaging materials.

2. Grouping Objects:

Basis of Grouping:
- Objects can be grouped based on different criteria such as shape, size, color, or material. Grouping helps in organizing and studying objects systematically.
- Examples:
  - Grouping by shape: Round objects (balls, apples), rectangular objects (books, boxes).
  - Grouping by material: Plastic objects (buckets, toys), metal objects (spoons, tools).
Activity: Grouping Objects:
- Collect various objects from your surroundings and try to group them based on different properties.
- For example, you can group objects made of plastic (toys, containers), or objects that are round in shape (balls, fruits).

3. Properties of Materials:

Appearance:
- Materials have different appearances based on their texture, color, and shine.
- Some materials have a shiny (lustrous) appearance, while others are dull.
- Examples:
  - Lustrous materials: Metals like gold, silver, iron, and aluminum.
  - Non-lustrous materials: Wood, plastic, and rubber.
Hardness:
- Hardness is a property that determines how resistant a material is to scratching or being compressed.
- Hard materials are difficult to scratch or compress, while soft materials can be easily scratched or compressed.
- Examples:
  - Hard materials: Metals (iron, steel), stone.
  - Soft materials: Sponge, cotton, rubber.
Solubility:
- Solubility refers to the ability of a substance to dissolve in a liquid (usually water).
- Soluble materials dissolve completely in water, while insoluble materials do not.
- Examples:
  - Soluble materials: Sugar, salt.
  - Insoluble materials: Sand, chalk powder.
Floatation:
- Some materials float on the surface of water, while others sink.
- This property depends on the density of the material compared to the density of water.
- Examples:
  - Float on water: Wood, plastic.
  - Sink in water: Stone, metal.
Transparency:
- Transparency refers to the ability of a material to allow light to pass through it.
- Transparent materials allow light to pass through clearly, translucent materials allow partial light, and opaque materials do not allow light to pass through.
- Examples:
  - Transparent materials: Glass, clear plastic.
  - Translucent materials: Frosted glass, butter paper.
  - Opaque materials: Wood, metal, cardboard.

4. Uses of Grouping:

Organization:
- Grouping materials helps in organizing objects efficiently, making it easier to locate and use them.
- Example: In a store, similar items are kept together, like all types of biscuits in one section and all types of soaps in another.
Study and Analysis:
- Grouping helps in studying the properties of materials systematically and finding patterns or similarities among them.
- Example: Grouping materials based on their conductivity can help in studying electrical properties.
Convenience:
- Grouping similar objects together makes daily tasks easier and more efficient.
- Example: In the kitchen, grouping utensils based on their use (cooking, serving) helps in quick access and organization.

5. Examples and Activities:

Activity 1: Collecting and Grouping Objects:
- Collect various objects from your surroundings (classroom, home, outdoors).
- Try to group these objects based on different properties like shape, material, or use.
- Example: Grouping objects made of paper (books, notebooks) and objects made of metal (spoons, nails).
Activity 2: Identifying Materials:
- Make a table listing various objects and identify the materials they are made of.
- Example:
  - Object: Pen | Material: Plastic, Metal
  - Object: Chair | Material: Wood, Metal, Plastic
Activity 3: Testing Hardness:
- Test the hardness of different materials by trying to scratch them with a metal key.
- Observe which materials are easily scratched (soft) and which are not (hard).
Activity 4: Testing Solubility:
- Take different solid substances (sugar, salt, sand, chalk powder) and try to dissolve them in water.
- Observe which substances dissolve completely (soluble) and which do not (insoluble).
Activity 5: Testing Floatation:
- Collect different materials (wood, plastic, metal, stone) and place them in water.
- Observe which materials float on the surface and which sink.
Activity 6: Testing Transparency:
- Take different materials (glass, plastic, paper) and try to see through them.
- Classify them as transparent, translucent, or opaque based on your observations.

Summary:

Objects and Materials: Objects around us are made from various materials like wood, plastic, metal, and glass.
Grouping Objects: Objects can be grouped based on properties like shape, material, and use.
Properties of Materials: Key properties include appearance, hardness, solubility, floatation, and transparency.
Uses of Grouping: Grouping helps in organizing, studying, and using objects efficiently.
Examples and Activities: Various activities help in understanding and testing the properties of materials.

By understanding these concepts, students can better appreciate the variety of materials around them and their properties, leading to more informed choices in everyday life.

Exam Preparation: 50 Questions and Answers

Multiple Choice Questions (MCQs)

Which of the following is a shiny material?
- A. Wood
- B. Iron
- C. Plastic
- D. Chalk
- Answer: B. Iron
Which material is used to make a tumbler for holding water?
- A. Cloth
- B. Glass
- C. Paper
- D. Cardboard
- Answer: B. Glass
Which of the following substances is soluble in water?
- A. Sand
- B. Sugar
- C. Sawdust
- D. Chalk powder
- Answer: B. Sugar
Which material is an example of a hard material?
- A. Sponge
- B. Cotton
- C. Stone
- D. Rubber
- Answer: C. Stone
Which of the following is a transparent material?
- A. Wood
- B. Glass
- C. Metal
- D. Cardboard
- Answer: B. Glass

Fill in the Blanks

A ______________ is used to hold liquids.
- Answer: Tumbler
Materials that have a shiny appearance are called ______________.
- Answer: Lustrous
Materials that can be easily compressed are called ______________.
- Answer: Soft
Wood is an example of a ______________ material.
- Answer: Hard
Oil is ______________ in water.
- Answer: Insoluble

Name the Following

Name two materials that are soluble in water.
- Answer: Salt, Sugar
Name two materials that are opaque.
- Answer: Wood, Metal
Name two materials that can float on water.
- Answer: Wood, Plastic
Name two materials that are transparent.
- Answer: Glass, Water

One Mark Questions

What is a material?
- Answer: A material is a substance from which objects are made.
Give one example of a translucent material.
- Answer: Frosted glass
What property of a material makes it suitable for making a tumbler?
- Answer: The ability to hold liquids without leaking.
Which material is used to make electrical wires?
- Answer: Copper
Is cotton a hard or soft material?
- Answer: Soft

Two Mark Questions

What is the difference between transparent and opaque materials?
- Answer: Transparent materials allow light to pass through them clearly, while opaque materials do not allow light to pass through.
Why is it important to group materials?
- Answer: Grouping materials helps in studying their properties systematically and makes it easier to locate and organize objects.
Explain with an example how one material can be used to make different objects.
- Answer: Wood can be used to make various objects such as tables, chairs, and doors.
What happens when a piece of chalk is added to water?
- Answer: The chalk does not dissolve and settles down, showing that it is insoluble in water.
What is meant by the hardness of a material?
- Answer: Hardness is the property of a material that determines its resistance to scratching or being compressed.

Three Mark Questions

Describe an activity to test the solubility of different substances in water.
- Answer: Collect samples of sugar, salt, sand, and sawdust. Add each sample to separate glasses of water and stir. Observe which substances dissolve completely (sugar, salt) and which do not (sand, sawdust).
Explain why materials like glass and plastic are used to store food items in shops.
- Answer: Glass and plastic are transparent, allowing customers to see the contents inside, and they also protect the food from contamination.
What are the properties of materials that determine their use in making objects?
- Answer: The properties include appearance, hardness, solubility, floatation, and transparency. These properties determine the suitability of materials for different purposes.
How can you test whether a given material is hard or soft?
- Answer: You can test by trying to scratch the material with a metal key. Materials that can be easily scratched are soft, while those that cannot be scratched easily are hard.
Why do some materials float on water while others sink?
- Answer: Materials that are less dense than water float, while those that are more dense sink. The density and the ability to displace water determine whether an object will float or sink.
Give three examples of materials that are used to make multiple types of objects and explain their uses.
- Answer:
  - Wood: Used to make furniture (tables, chairs), construction (doors, windows), and utensils (spoons, bowls).
  - Plastic: Used to make containers (bottles, boxes), household items (toys, utensils), and industrial products (pipes, fittings).
  - Metal: Used to make tools (hammers, screwdrivers), household items (utensils, cutlery), and structures (bridges, buildings).

Practice Questions

Name five objects which can be made from wood.
- Answer: Table, chair, door, window frame, spoon
Select those objects from the following which shine: Glass bowl, plastic toy, steel spoon, cotton shirt.
- Answer: Glass bowl, steel spoon
Match the objects with the materials they are made of.
- Answer:
  - Book: Paper
  - Tumbler: Glass
  - Chair: Wood
  - Toy: Plastic
  - Shoes: Leather
State whether the following statements are True or False:
- Answer:
  - Stone is transparent, while glass is opaque. (False)
  - A notebook has lustre while an eraser does not. (False)
  - Chalk dissolves in water. (False)
  - A piece of wood floats on water. (True)
  - Sugar does not dissolve in water. (False)
  - Oil mixes with water. (False)
  - Sand settles down in water. (True)
  - Vinegar dissolves in water. (True)
Group the following objects as round shaped and other shapes: Water, basketball, orange, sugar, globe, apple, earthen pitcher.
- Answer:
  - Round shaped: Basketball, orange, globe, apple
  - Other shapes: Water, sugar, earthen pitcher
List all items known to you that float on water.
- Answer: Wood, plastic bottle, cork, foam, leaf
Find the odd one out from the following:
- Answer:
  - Chair, Bed, Table, Baby, Cupboard (Odd: Baby)
  - Rose, Jasmine, Boat, Marigold, Lotus (Odd: Boat)
  - Aluminium, Iron, Copper, Silver, Sand (Odd: Sand)
  - Sugar, Salt, Sand, Copper sulphate (Odd: Sand)
Give an example of an object that is made of more than one material.
- Answer: A pencil (wood, graphite, rubber)
Why are metals used to make utensils?
- Answer: Metals are durable, conduct heat well, and are hard, making them suitable for cooking utensils.
What are the uses of grouping materials in our daily life?
- Answer: Grouping materials helps in organizing, locating objects easily, and studying their properties systematically.
Explain the term ‘solubility’.
- Answer: Solubility is the property of a substance to dissolve in a solvent, forming a homogeneous mixture.
How do you test the transparency of a material?
- Answer: Hold the material up to light and observe if you can see through it clearly (transparent), partially (translucent), or not at all (opaque).
Give two examples each of transparent, translucent, and opaque materials.
- Answer:
  - Transparent: Glass, clear plastic
  - Translucent: Frosted glass, oiled paper
  - Opaque: Wood, metal
What property makes plastic suitable for making containers?
- Answer: Plastic is durable, lightweight, and can be molded into various shapes, making it ideal for containers.
Explain why wood is used to make furniture.
- Answer: Wood is strong, durable, and aesthetically pleasing, making it a good material for furniture.
Describe an activity to check the hardness of different materials.
- Answer: Try to scratch different materials with a metal key. Materials that can be scratched easily are soft, while those that resist scratching are hard.
Why is water considered a universal solvent?
- Answer: Water can dissolve a wide variety of substances, making it essential for many biological and chemical processes.
What are the factors that affect whether a material will float or sink in water?
- Answer: The density of the material compared to water and its ability to displace water determine whether it will float or sink.
How can you test the solubility of a liquid in water?
- Answer: Mix the liquid with water and observe if it forms a homogeneous mixture (soluble) or separates into layers (insoluble).
Why is it important to understand the properties of materials?
- Answer: Understanding the properties of materials helps us choose the right material for specific purposes and use them effectively in daily life.

These questions and detailed notes cover various aspects of the chapter “Sorting Materials into Groups” and will help students prepare comprehensively for their exams.

Here is the collection of images depicting different aspects of sorting materials into groups, including various objects made from different materials, a child grouping objects based on shape and material, an activity testing the solubility of different substances in water, an experiment showing which materials float or sink in water, and transparent, translucent, and opaque materials being tested for their transparency properties. These images can help visualize the concepts discussed in the chapter.

Here is the educational illustration showing the difference between transparent and opaque materials. The image depicts transparent materials like glass allowing light to pass through clearly and opaque materials like wood not allowing light to pass through. This visual aid should help students understand the concept more effectively.

Here is the educational illustration showing what happens when a piece of chalk is added to water. The image depicts a piece of chalk in a glass of water with the chalk settling at the bottom, indicating that it does not dissolve and is insoluble in water. This should help 6th standard students easily understand the concept.

Here is the educational illustration showing an activity to test the solubility of different substances in water. The image depicts four glasses of water labeled ‘sugar’, ‘salt’, ‘sand’, and ‘sawdust’, with each substance being stirred with a spoon. It shows sugar and salt dissolving completely while sand and sawdust remain undissolved at the bottom. This clear and simple illustration should help students easily understand the activity.

Here is the realistic photo showing examples of transparent, translucent, and opaque materials. The image includes a piece of glass and clear plastic for transparent materials, frosted glass and oiled paper for translucent materials, and wood and metal for opaque materials. Each type of material is clearly visible and identifiable, helping students understand the differences.

Here is the realistic photo showing various plastic containers, such as bottles, boxes, and tubs. This image highlights the properties that make plastic suitable for containers: its durability, lightweight nature, and ability to be molded into various shapes. This should help students understand why plastic is ideal for making containers.