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

Introduction to Fibre to Fabric

The chapter "Fibre to Fabric" in Class 7 NCERT Science introduces students to the basic materials used to make clothes. Fibres are thin strands that come from plants, animals, or synthetic sources. These fibres are then processed to create fabric, which is used to make garments. Understanding this process helps students appreciate the origin of everyday clothing and the science behind textile production.

Key points:

• Fibre is the raw material for fabric
• Fabric is made by joining fibres
• The chapter explains natural and synthetic fibres

This knowledge is essential for Class 7 students preparing for CBSE exams.

Types of Fibres: Natural and Synthetic

Fibres are broadly classified into two types:

1. Natural Fibres: Obtained from plants and animals.

• Plant fibres include cotton, jute, flax, and coir.
• Animal fibres include wool, silk, and alpaca.

2. Synthetic Fibres: Man-made fibres produced from chemicals.

• Examples include nylon, polyester, and acrylic.

Natural fibres are eco-friendly but may wrinkle easily, while synthetic fibres are strong but less breathable. Understanding these differences helps in choosing the right fabric.

From Fibre to Yarn: The Spinning Process

Spinning is the process of converting fibres into yarn. Yarn is a continuous strand made by twisting fibres together. This step is crucial before fabric can be made.

Steps in Spinning:

• Cleaning fibres to remove impurities
• Aligning fibres parallel to each other
• Twisting fibres to form yarn

A simple example is the spinning wheel, which twists cotton fibres into yarn. The strength of yarn depends on the amount of twist; more twist means stronger yarn.

Worked Example: If 100 fibres are twisted to form a yarn, and each fibre is 10 cm long, the yarn length will be approximately 10 cm but stronger due to twisting. The formula for yarn strength depends on fibre strength and twist level.

Weaving: Turning Yarn into Fabric

Weaving is the process of interlacing two sets of yarns at right angles to make fabric.

• The longitudinal yarns are called warp.
• The transverse yarns are called weft.

The weaving machine or loom helps in this process. The pattern of weaving affects the texture and strength of the fabric.

Types of Weaves:

• Plain weave
• Twill weave
• Satin weave

Each weave has unique properties. For example, plain weave is simple and strong, while satin weave is smooth and shiny.

This process transforms yarn into usable fabric for clothes, upholstery, and more.

Special Fabrics: Knitting and Felting

Apart from weaving, fabrics can also be made by knitting and felting.

• Knitting involves looping yarns to create stretchable fabric. It is used for making sweaters, socks, and gloves.
• Felting is the process of matting fibres together using heat, moisture, and pressure. Wool is commonly felted to make thick, warm fabrics.

These methods produce fabrics with different textures and uses compared to woven fabrics.

Understanding these techniques broadens knowledge of fabric production beyond weaving.

Importance of Fibre to Fabric in Daily Life

The journey from fibre to fabric is essential for producing clothing, household textiles, and industrial materials.

• Clothes protect us and express culture.
• Different fibres suit different climates (e.g., cotton for summer, wool for winter).
• The textile industry is a major part of India's economy.

Learning this chapter helps students appreciate the science behind everyday materials and the effort involved in fabric production.

It also encourages sustainable choices by understanding fibre sources.