Explain yarn twist and its effect on yarn and fabric.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in two lines. Twist is the spiral turning of fibres round the yarn axis that holds them together. It is measured in turns per inch or per metre.
2 · Draw S and Z twist. [Sketch: two upright yarns, one with spirals sloping like the middle of S, one like the middle of Z]
3 · Amount of twist.
Soft: weft, napped and knitting yarns.
Medium: most weaving yarns.
Hard: warp, voile.
Crepe: georgette, crepe.
4 · Effects of twist.
Strength rises to an optimum, then falls.
Less lustre and absorbency with more twist.
Less pilling with more twist; crepe kinks.
5 · Daily-life link. Soft-twist terry for absorbent kitchen towels; wash crepe saris cool to stop shrinkage.
6 · Close in one line. Twist direction and amount together decide a yarn's strength, look and feel.
Scoring tip: The S and Z sketch is worth drawing even in a 2-mark answer.
