Class 6 Science Notes Chapter 3 (Chapter 3) – Examplar Problem Book

Alright class, let's get straight into Chapter 3, 'Fibre to Fabric'. This is a fundamental chapter, and understanding the basics here is crucial, not just for your class exams but also for various competitive government exams where general science is a component. We'll go through the key concepts based on your NCERT textbook and Exemplar problems.

Chapter 3: Fibre to Fabric - Detailed Notes

1. Introduction: What are Fibres and Fabrics?

• Fibre: The basic, thin thread-like strand from which yarns are made. Think of it as the fundamental building block. Fibres can be natural or synthetic.
• Yarn: A continuous strand made by twisting or spinning fibres together. Yarns are then used to make fabrics. (Imagine twisting cotton wool to make a long thread – that's yarn).
• Fabric: Material made by weaving or knitting yarns together. This is what your clothes, bedsheets, curtains, etc., are made of. Also called cloth.

2. Variety in Fabrics

• Fabrics differ in texture, appearance, and properties (like absorbency, warmth, strength).
• Examples: Cotton (soft, absorbent), Silk (smooth, lustrous), Wool (fluffy, warm), Jute (rough, strong), Nylon/Polyester (strong, quick-drying).

3. Types of Fibres

Fibres are broadly classified into two main types:

• A. Natural Fibres: Obtained from natural sources – plants or animals.

  • i. Plant Fibres: Obtained from plants.

    • Cotton:
      • Source: Fruit of the cotton plant, called cotton bolls.
      • Climate/Soil: Requires warm climate and black soil.
      • Process:
        • Harvesting: Cotton bolls are picked (by hand or machine).
        • Ginning: The process of separating cotton fibres from the seeds. Done using combs or machines.
      • Uses: Clothing (shirts, trousers, sarees), bedsheets, towels, bandages.
    • Jute:
      • Source: Stem of the jute plant.
      • Climate/Soil: Requires rainy season, alluvial soil. Cultivated mainly in West Bengal, Bihar, Assam.
      • Process:
        • Harvesting: Done at the flowering stage.
        • Retting: Stems are immersed in water for a few days to rot the stem tissues, making it easy to separate the fibres.
        • Fibre Separation: Done by hand.
      • Uses: Gunny bags, ropes, mats, carpets, shopping bags. Often called the 'Golden Fibre'.
    • Other Plant Fibres (Brief):
      • Coir: From the outer husk of coconut. Used for ropes, mats, mattresses.
      • Flax: From the stem of the flax plant. Used to make linen fabric.

  • ii. Animal Fibres: Obtained from animals.

    • Wool:
      • Source: Fleece (hair) of sheep, goat (Kashmiri, Angora), yak, camel, llama, alpaca.
      • Process:
        • Shearing: Removing the fleece from the animal.
        • Scouring: Washing the sheared wool to remove grease, dust, dirt.
        • Sorting: Separating wool based on texture.
        • Dyeing: Colouring the fibres.
        • Spinning: Twisting fibres into yarn.
      • Uses: Sweaters, shawls, carpets, blankets. Provides warmth.
    • Silk:
      • Source: Cocoons of silkworms (larva of the silk moth).
      • Process:
        • Sericulture: Rearing of silkworms to obtain silk.
        • Silkworms feed on mulberry leaves.
        • They secrete a protein fibre that hardens on exposure to air, forming the cocoon around themselves.
        • Cocoons are boiled or treated with steam to kill the pupa inside and loosen the silk filament.
        • Reeling: The process of unwinding the silk filament from the cocoon.
      • Uses: Sarees, dresses, scarves, ties. Known for its lustre and softness.

• B. Synthetic (Man-made) Fibres: Made by humans from chemical substances (mostly petroleum-based).

  • Examples: Nylon, Polyester, Rayon (semi-synthetic, made from wood pulp), Acrylic.
  • Properties: Generally strong, durable, dry quickly, less expensive than some natural fibres, wrinkle-resistant.
  • Caution: They melt on heating, so not suitable for kitchen or laboratory work near flames.

4. From Fibre to Fabric: Key Processes

• A. Spinning:

  • Definition: The process of making yarn from fibres.
  • How it works: Fibres from a mass (like cotton wool) are drawn out and twisted simultaneously. This brings the fibres together to form a strong yarn.
  • Devices:
    • Hand spindle (Takli)
    • Spinning wheel (Charkha - popularised by Mahatma Gandhi during the independence movement as a symbol of self-reliance)
    • Spinning machines (used on a large scale).

• B. Weaving:

  • Definition: The process of arranging two sets of yarns together perpendicularly to make a fabric.
  • How it works: One set of yarn runs lengthwise (warp) and the other runs crosswise (weft).
  • Devices:
    • Looms: Machines used for weaving. Can be hand-operated (Handlooms) or power-operated (Powerlooms). (Think of how a mat is made by interlacing strips).

• C. Knitting:

  • Definition: The process of making fabric by using a single yarn to form interlocking loops.
  • How it works: A single continuous yarn is looped together. (Think of how sweaters or socks are made). Can pull a thread and the whole fabric might unravel.
  • Methods: Can be done by hand (using knitting needles) or by machines.

5. History of Clothing Material

• Ancient Times: People used bark, big leaves, animal skins, and fur for covering themselves.
• Agricultural Communities: Learned to weave twigs and grass into mats and baskets. Vines, animal fleece, or hair were twisted into long strands, which were then woven into fabrics.
• Early Indians: Wore fabrics made of cotton grown near the River Ganga. Flax was also cultivated in ancient Egypt.
• Stitching: Invention of the sewing needle allowed people to stitch fabrics to make fitted clothes. Even today, unstitched fabrics like sarees, dhotis, lungis, and turbans are widely used.

Key Takeaways for Exams:

• Know the definitions of fibre, yarn, fabric, ginning, spinning, weaving, knitting, retting, shearing, sericulture, reeling.
• Be able to classify fibres (Natural/Synthetic, Plant/Animal).
• Know the specific sources of common fibres (e.g., Cotton from bolls, Jute from stem, Wool from fleece, Silk from cocoon).
• Understand the basic processes involved in converting fibre to fabric.
• Remember key examples of each type of fibre and their common uses.
• Note the difference between weaving (two sets of yarn) and knitting (single yarn).

Multiple Choice Questions (MCQs)

Here are 10 MCQs based on Chapter 3 to test your understanding:

1. Which part of the cotton plant yields cotton fibre?
   (a) Stem
   (b) Leaf
   (c) Root
   (d) Fruit (Cotton boll)

2. The process of separating cotton fibres from their seeds is called:
   (a) Spinning
   (b) Ginning
   (c) Weaving
   (d) Retting

3. Jute fibre is obtained from which part of the jute plant?
   (a) Flower
   (b) Stem
   (c) Root
   (d) Seed

4. Which of the following is an animal fibre?
   (a) Cotton
   (b) Jute
   (c) Silk
   (d) Flax

5. The process of making yarn from fibres is known as:
   (a) Weaving
   (b) Knitting
   (c) Ginning
   (d) Spinning

6. Which process uses two sets of yarns arranged together to make a fabric?
   (a) Knitting
   (b) Spinning
   (c) Weaving
   (d) Reeling

7. Sweaters and socks are commonly made using which process?
   (a) Weaving
   (b) Ginning
   (c) Knitting
   (d) Retting

8. Which of the following is a synthetic fibre?
   (a) Wool
   (b) Cotton
   (c) Nylon
   (d) Silk

9. Sericulture is the practice of rearing:
   (a) Sheep for wool
   (b) Cotton plants for fibre
   (c) Silkworms for silk
   (d) Jute plants for fibre

10. Which of these fibres is obtained from the fleece of sheep or goat?
    (a) Jute
    (b) Wool
    (c) Cotton
    (d) Coir

Answer Key:

1. (d)
2. (b)
3. (b)
4. (c)
5. (d)
6. (c)
7. (c)
8. (c)
9. (c)
10. (b)

Study these notes carefully. Focus on the terms, sources, and processes. Let me know if any part needs further clarification! Good luck with your preparation.