Describe the manufacture of silk. Add its properties and uses.

How to lay out the answer. Follow the frame, then write it in your own words.

1 · Open in two lines. Silk is a natural protein filament spun by the silkworm. Sericulture is the rearing of silkworms to obtain raw silk.
2 · Draw the life cycle. [Cycle: egg → larva (feeds on mulberry, spins cocoon) → pupa in cocoon → moth → egg; mark where stifling stops it]
3 · Rearing and stifling. Larvae are fed mulberry leaves and spin cocoons; cocoons are heated to kill the pupa before the moth breaks the filament.
4 · Reeling and throwing.
- Cocoons soaked in hot water; ends of several unwound together into raw silk.
- Raw silk twisted and plied: organzine (warp), tram (weft), crepe.
5 · Degumming and spun silk. Soap boiling removes sericin, giving soft, lustrous silk; waste silk is cut and spun into spun silk.
6 · Properties.
- Triangular cross-section gives lustre.
- Strong for its fineness; weaker wet.
- Absorbent, light and warm.
- Damaged by alkali, chlorine bleach, sweat and sunlight.
7 · Daily-life link. Saris and wedding wear; wash with mild soap in cool water, no chlorine bleach, dry in shade.
8 · Close in one line. Lustre, strength and drape make silk the queen of fibres, and India produces all its commercial kinds.

Scoring tip: Name the Indian silks (mulberry, tasar, eri, muga) in one line each; examiners reward the local examples.