What is Fibre to Fabric Class 7: Complete Science Guide

Introduction to Fibre to Fabric in Class 7 Science

In Class 7 Science, the chapter "Fibre to Fabric" introduces students to the basic concept of how fibres are transformed into fabric. Fibres are thin, thread-like structures that can be spun into yarn and then woven or knitted to make fabric. This process is important because fabric is used to make clothes and other textiles. The chapter covers both natural fibres like cotton and wool, and synthetic fibres such as nylon and polyester.

Understanding this process helps students appreciate the origin of the clothes they wear and the science behind textile production.

Types of Fibres: Natural and Synthetic

Fibres are mainly classified into two types:

• Natural Fibres: These come from plants and animals.
• Plant-based fibres include cotton, jute, and flax.
• Animal-based fibres include wool and silk.

• Synthetic Fibres: These are man-made fibres produced from chemicals.
• Examples include nylon, polyester, and acrylic.

Natural fibres are biodegradable and breathable, making them comfortable to wear. Synthetic fibres are strong and durable but may not be as breathable. Knowing the difference helps in choosing the right fabric for different uses.

The Process of Turning Fibre into Fabric

The journey from fibre to fabric involves several steps:

1. Obtaining the Fibre: Fibres are collected from plants (like cotton bolls) or animals (like sheep for wool). 2. Cleaning: The fibres are cleaned to remove dirt and impurities. 3. Spinning: Fibres are twisted together to form yarn or thread. 4. Weaving or Knitting: Yarn is woven on looms or knitted to create fabric. 5. Finishing: The fabric is treated to improve texture, colour, and durability.

Each step is crucial to ensure the fabric is strong, smooth, and suitable for making clothes.

Spinning: How Fibres Become Yarn

Spinning is the process of twisting fibres to make yarn. It increases the strength of the fibres by binding them together. There are two main types of spinning:

• Hand Spinning: Using a spinning wheel or spindle.
• Machine Spinning: Using modern machines for faster production.

For example, cotton fibres are cleaned and then spun into yarn. The formula for yarn strength depends on the twist per inch (TPI):

$$ \text{Yarn Strength} \propto \text{TPI} $$

More twists generally mean stronger yarn, but too many twists can make it stiff.

Weaving and Knitting: Making Fabric from Yarn

Once yarn is ready, it is converted into fabric by weaving or knitting:

• Weaving: Interlacing two sets of yarns at right angles using a loom.
• Knitting: Looping yarns together using needles.

Both methods produce different fabric textures and uses.

Common Fabrics and Their Fibre Sources

Different fabrics come from different fibres:

• Cotton fabric: Made from cotton fibres; soft and breathable.
• Silk fabric: Made from silk fibres; smooth and shiny.
• Woollen fabric: Made from wool; warm and insulating.
• Synthetic fabrics: Made from nylon, polyester; durable and water-resistant.

Understanding fabric types helps in selecting the right material for clothes, upholstery, and other uses.