Chapter 3: Fibre to Fabric
रेशों से वस्त्र तक (ऊन का प्रसंस्करण, छंटाई रोग/एन्थ्रेक्स, रेशम कीट जीवन चक्र, सेरीकल्चर)
Don't Let a 20-Minute Bubbling Delay Cost You CTET Qualification
In offline CTET exams, bubbling 150 bubbles takes 18 to 22 minutes of mechanical time. A single misaligned row can trigger an 8-question domino error. Practice bubble-filling this chapter's solved MCQs inside Mentora's official OMR simulator.
- Animal Fibres Chemistry: Wool and Silk are PROTEIN fibres (unlike cotton and jute, which are plant cellulose). Burning wool or silk smells like burning hair; burning cotton smells like burning paper.
- Wool Sources: Sheep, Yak (Tibet and Ladakh), Angora goat (found in Jammu & Kashmir, yields luxurious Angora wool), Kashmiri goat (soft under-fur woven into fine Pashmina shawls), Camel, Llama, and Alpaca (South America).
- Sequential Steps in Wool Processing (Strict Chronology for CTET):
- 1. Shearing (ऊन की कटाई): Shaving the fleece of sheep along with thin uppermost dead skin layer. Painless; conducted in spring/summer so sheep survive without protective fleece.
- 2. Scouring (अभिमार्जन): Washing sheared fleece in large wash tanks with hot water and detergent to thoroughly strip away grease, perspiration, dust, and dirt.
- 3. Sorting (छंटाई): Separating hairy fleece into grades based on texture, thickness, and length.
- 4. Burr Picking (बर की छंटाई): Combing out small, fluffy tangled knots called burrs.
- 5. Dyeing (रंगाई): Natural fleece is black, brown, or white; fibres are dyed into vibrant colors.
- 6. Rolling / Spinning (लपेटकर धागा बनाना): Fibres straightened, combed, and spun into wool yarn.
- Occupational Hazard: Sorter's Disease (सॉर्टर रोग) is a fatal bacterial infection of the bloodstream caused by *Bacillus anthracis* (Anthrax bacterium) prevalent among wool processing sorters.
- Silk Life Cycle & Sericulture: Female silk moth lays eggs $ ightarrow$ Hatch into larvae called Caterpillars or Silkworms $ ightarrow$ Feed voraciously on Mulberry (*Morus alba*) leaves for 25-30 days $ ightarrow$ Silkworm moves head in figure-eight ('8') pattern and secretes liquid protein fibre that solidifies into silk on air contact $ ightarrow$ Encases itself completely into a Cocoon (कोकून) $ ightarrow$ Cocoons boiled in hot water to soften sericin gum and unwind the raw silk filament (Reeling / रीलिंग).
- Trap: What is the biological composition of silk and wool? Correct: PROTEIN. Cotton and linen are carbohydrates (cellulose).
- Trap: What causes Sorter's disease in wool industry workers? Correct: A BACTERIUM (*Bacillus anthracis*), NOT a virus or fungus.
- Trap: In which stage of the silk moth life cycle is silk fibre harvested? Correct: THE COCOON STAGE, before the adult moth emerges by breaking the continuous silk filament.
NCERT Core Facts: Animal Fibres (Wool & Silk Processing)
Every single CTET Paper 2 science section contains questions on wool production stages or the silkworm lifecycle:
1. Chronological Sequence of Wool Processing
[1. Shearing (कटाई)] ──> [2. Scouring (अभिमार्जन)] ──> [3. Sorting (छंटाई)]
│
[6. Rolling (कताई)] <── [5. Dyeing (रंगाई)] <── [4. Burr Picking (बर)]- Shearing: Cut without bleeding because the outermost skin layer consists of dead keratinized cells.
- Scouring: Machine or tank washing to strip natural greasy sebum and dirt.
- Sorter's Disease: An occupational disease caused by Bacillus anthracis affecting wool factory workers.
2. Silkworm Life Cycle & Sericulture Facts
- Silk rearing is called Sericulture (रेशम कीट पालन).
- Silkworms feed exclusively on fresh leaves of the Mulberry tree (*Morus alba*).
- The silk thread consists of structural proteins (Fibroin glued with Sericin).
- Reeling of Silk (रेशम की रीलिंग): The mechanical process of separating and unwinding fine silk threads from cocoons soaked in hot boiling water.
- A single silk filament can be over 1,000 meters long, having tensile strength comparable to steel wire of identical diameter!
Test Your Mastery: Fibre to Fabric
Authentic CBSE exam questions tested directly from this NCERT chapter.
Which of the following represents the correct sequential order of steps followed in the processing of wool from sheared fleece to yarn?
कटे हुए ऊन से धागा बनाने तक ऊन के प्रसंस्करण में अपनाए जाने वाले चरणों का सही क्रम निम्नलिखित में से कौन-सा है?
A burning test is performed on two unknown fabric strips, P and Q. Strip P burns with the distinct smell of burning hair, while strip Q burns with the smell of burning paper. Strips P and Q are most likely made of:
दो अज्ञात कपड़ों की पट्टियों P और Q पर दहन परीक्षण किया जाता है। पट्टी P जलते हुए बालों की गंध के साथ जलती है, जबकि पट्टी Q जलते हुए कागज की गंध के साथ जलती है। पट्टियाँ P और Q संभवतः किसकी बनी हैं?
What chemical substance is silk fibre made of?
Silk fibre is a natural protein secreted by the salivary glands of the silkworm caterpillar.
What is Sorter's disease, and who is at risk?
It is a severe pulmonary/systemic blood infection caused by the bacterium Bacillus anthracis, historically contracted by workers sorting infected animal wool.