Fibre to Fabric Class 7 Notes | YoLearn.ai

Key Points: Must Remember for Fibre to Fabric

• Fibre is the basic unit from which yarn is made, and yarn is then made into fabric.
• Natural fibres are obtained from plants (e.g., cotton, jute) or animals (e.g., wool, silk).
• Synthetic fibres are man-made, such as nylon, polyester, and acrylic.
• Wool is obtained primarily from sheep, but also from yak, goat, camel, alpaca, and llama.
• The process of obtaining wool involves shearing, scouring, sorting, dyeing, and spinning.
• Silk is an animal fibre obtained from the cocoons of silkworms (Bombyx mori).
• The rearing of silkworms for silk production is called sericulture.
• The process of obtaining silk from cocoons involves reeling, where silk threads are separated.
• Fibres are converted into yarn by spinning and then into fabric by weaving or knitting.

Essential Definitions for Fibre to Fabric

Fibre

A thin, thread-like strand from which cloth or paper is made.

Yarn

A continuous strand of fibres suitable for weaving, knitting, or otherwise intertwining to form textile fabrics.

Fabric

A material made by weaving or knitting fibres together; also known as cloth or textile.

Shearing

The process of removing the fleece of a sheep along with a thin layer of skin.

Scouring

The process of washing the sheared wool in tanks to remove grease, dust, and dirt.

Sorting

Separating wool of different textures after scouring.

Sericulture

The rearing of silkworms for the production of silk.

Cocoon

The silky case spun by the larvae of many insects (especially moths) for protection as pupae; the source of silk fibre.

Reeling

The process of unwinding the silk threads from the cocoons.

Weaving

The process of interlacing two sets of yarn at right angles to make fabric.

The Journey of Wool: From Sheep to Soft Garment

Wool, a prominent natural animal fibre, has been cherished for centuries due to its warmth and durability. The production of wool involves several key steps, starting right from the farm. First, the sheep are reared, meaning they are bred and cared for, typically in regions with temperate climates like hills and mountains. These sheep develop a thick coat of hair, known as fleece, which traps air and keeps them warm. This fleece is the raw material for wool production. The first crucial step in processing this fleece is shearing, where the fleece, along with a very thin layer of dead skin, is carefully removed from the sheep's body. This process is usually done in warm weather to prevent the sheep from feeling cold and is similar to getting a haircut, not harming the animal.

After shearing, the raw wool contains a lot of grease, dust, and dirt. To clean it, the sheared fleece undergoes scouring, where it is thoroughly washed in large tanks, either manually or by machines. Once clean, the wool is sent for sorting. In this stage, wool of different textures is separated. For example, finer wool might be sorted for high-quality garments, while coarser wool might be used for carpets. Small fluffy fibres called burrs are picked out from the wool, which are then again scoured and dried. The fibres are then dyed in various colours, as the natural fleece of sheep, goats, and camels is usually white, brown, or black. Finally, the dyed fibres are straightened, combed, and rolled into yarn. The longer fibres are made into wool for sweaters, while shorter fibres are spun and woven into woollen cloth. This intricate process ensures that the soft, warm wool we wear is of the highest quality, providing comfort and protection against cold weather.

The Lifecycle of Silk: From Silkworm to Saree

1. Rearing Silkworms — Female silkworms lay hundreds of tiny eggs. These eggs are stored carefully under hygienic conditions and suitable temperature and humidity.
2. Hatching and Feeding — When the mulberry leaves are fresh, the eggs are warmed to a suitable temperature. The larvae hatch from the eggs, known as caterpillars or silkworms. They are fed on fresh mulberry leaves and grow in size over 25-30 days.
3. Cocoon Formation — After growing, the silkworms stop eating and move to a tiny chamber of bamboo in the tray to spin cocoons. They secrete a protein fibre that hardens on exposure to air, forming the silk thread. The silkworm completely covers itself with this thread, forming the cocoon.
4. Processing Cocoons — A pile of cocoons is used for obtaining silk fibres. The cocoons are kept under the sun or boiled or exposed to steam. This helps separate the silk fibres.
5. Reeling the Silk — The process of taking out threads from the cocoon for use as silk is called reeling the silk. Special machines are used, which unwind the threads or fibres of silk from the cocoon. This raw silk is then spun into silk threads.

Natural vs. Synthetic Fibres: A Quick Comparison

Exam Tip: Mastering Fibre and Fabric Questions

When answering questions about 'Fibre to Fabric,' always pay close attention to the keywords used in the question. For example, if asked about 'process of obtaining wool,' remember the sequence: Shearing → Scouring → Sorting → Drying → Dyeing → Spinning. Similarly, for silk, remember Sericulture details. Be prepared to explain why each step is important (e.g., why scouring is done). Diagrams can fetch extra marks if the question allows, so practice drawing simple flowcharts for the processes. Also, differentiate clearly between natural and synthetic fibres and provide relevant examples for each. For animal fibres like wool and silk, memorize the specific animals they come from and their unique properties. Don't confuse the larval stage of a silkworm with its cocoon, or the reeling process with weaving. Precise definitions are key to scoring full marks.

Quick Check Your Knowledge

• Q: What is sericulture? A: Sericulture is the rearing of silkworms for obtaining silk.
• Q: Name any two animals that yield wool. A: Sheep and Yak.
• Q: What are the main steps involved in processing wool after shearing? A: The main steps are scouring, sorting, dyeing, and spinning.
• Q: Differentiate between weaving and knitting. A: Weaving is the process of interlacing two sets of yarn at right angles to make fabric, while knitting is done by using a single yarn to make a piece of fabric (often done with knitting needles or machines).

Frequently Asked Questions