Fibre to Fabric Class 7 PDF: Complete Science Guide for NCERT

Introduction to Fibre and Fabric

Fibres are thin, thread-like structures that are the building blocks of fabric. Fabric is made by joining these fibres through processes like spinning and weaving. In Class 7 Science, the chapter 'Fibre to Fabric' explains how natural fibres such as cotton and wool are obtained and converted into usable cloth.

Fibres can be broadly classified into:

• Natural fibres: Obtained from plants (cotton) or animals (wool, silk).
• Synthetic fibres: Man-made fibres like nylon and polyester (covered in higher classes).

Understanding these basics helps students grasp how everyday clothes are made from raw materials.

Types of Natural Fibres: Plant and Animal Origin

Natural fibres come from two main sources:

1. Plant fibres (Cellulose fibres):

• Example: Cotton, jute, flax
• Obtained from seeds, stems, or leaves of plants
• Cotton is the most common plant fibre used in textiles

2. Animal fibres (Protein fibres):

• Example: Wool from sheep, silk from silkworms
• These fibres are made of proteins like keratin (wool) and fibroin (silk)

Knowing these types helps Class 7 students identify fibres in their daily life.

From Fibre to Yarn: The Spinning Process

Spinning is the process of converting fibres into yarn, which is a continuous thread used for making fabric. The steps involved are:

• Cleaning: Removing dirt and impurities from fibres
• Carding: Aligning fibres parallel to each other
• Drawing: Stretching and thinning the fibres
• Spinning: Twisting fibres to form yarn

Example: Cotton fibres are cleaned and carded before spinning into soft yarn. The yarn’s strength depends on the tightness of the twist.

Formula for yarn twist (simplified):

$$ \text{Twist} = \frac{\text{Number of turns}}{\text{Length of yarn}} $$

This process is essential to produce strong and smooth yarn suitable for weaving.

Weaving: Making Fabric from Yarn

Weaving is the method of interlacing two sets of yarns at right angles to make fabric. The two yarn sets are:

• Warp: Longitudinal yarns held tight on a loom
• Weft: Horizontal yarns woven over and under the warp

The weaving process involves:

• Setting up the warp yarns on the loom
• Passing the weft yarns through the warp
• Interlacing them to form fabric

This is how cotton yarn is turned into cotton cloth used for clothes.

Comparison table of fibre to fabric stages:

Silk Production: From Silkworm to Fabric

Silk is a natural animal fibre obtained from silkworms. The process of silk production is called sericulture.

Steps involved:

• Silkworms spin cocoons made of silk fibre
• Cocoons are carefully unwound to extract silk threads
• Threads are spun into yarn
• Yarn is woven into silk fabric

Silk fabric is smooth, shiny, and highly valued for clothing. Class 7 students learn about this unique fibre and how it differs from wool and cotton.

Importance of Fibre to Fabric in Daily Life and Exams

Understanding the journey from fibre to fabric helps students appreciate the clothes they wear and the work involved in making textiles.

For Class 7 NCERT Science exams:

• Focus on definitions and key terms
• Learn the steps of spinning and weaving
• Identify natural fibres and their sources
• Practice diagrams like the cotton plant, silkworm, and weaving loom

Regular revision with the Fibre to Fabric Class 7 PDF can boost exam confidence and improve conceptual clarity.