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NIOS Class 12 Home Science Chapter 23 Year and Its Construction
Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Home Science Chapter 23 Year and Its Construction, NIOS Senior Secondary Course Home Science Solutions for All Chapter, You can practice these here.
Year and Its Construction
Chapter: 23
MODULE – V: TEXTILES AND CLOTHING
TEXTUAL QUESTIONS
INTEXT QUESTIONS 23.1
Q. 1. Fill in the blanks using the letters in the treasure chest. Each letter can be used more than once.
(i) Chemical spinning involves making a __________ solution, passing the solution through a __________ and __________ into fibre form.
Ans: spinning, spinnerette, solidifying.
(ii) Spinning can be done using a spindle, __________ or __________.
Ans: spinning wheel, spinning machine.
(iii) Spun yarns are made from __________ fibres and filament yarns from __________ fibres.
Ans: staple, filament.
(iv) Two types of blends are __________ and __________.
Ans: cotswool, terycot.
INTEXT QUESTIONS 23.2
Q. 1. Difference between the following:
(i) Single yarn and ply yarn.
Ans: A single yarn is a strand of fibres all twisted in the same direction.
A ply yarn is formed by twisting two or more single yarns together usually with a twist opposite that used in singles. A ply yarn is stronger than a single yarn.
(ii) Cord yarn and core yarn.
Ans: Cord is made by twisting ply yarns together.
In most cases fancy yarns have a multithread structure composed of such components-core, effect, and binder. The core yarn is the basis of the fancy yarn. The effects (twisted into knots, loops, etc.) are formed by effect yarn, which unites with the core yarn and it is supplied twisting field with higher speed. The yarn used parallel to the braid axis in the core or between braided layers.
(iii) Complex yarn and Textured yarn.
Ans: A fancy yarn is mostly complex in construction. It is also more costly compared to plain yarn. A fancy yarn is mostly complex in construction. Fancy yarn when made has consciously added variations in form, colour, or both for beauty.
Filament yarns may be flat or texturized complex yarn has a variable appearance along length.
(iv) Thread and Yarn.
Ans: Thread is a tightly twisted strand of two or more plys of yarn that are circular when cut in cross section. A thread and yarn are similar but not the same. A yarn is processed further to make a thread.
Q. 2. Justify the following statements giving examples where ever applicable.
(i) A high amount of twist brings in the crinkle effect in the yarn.
Ans: Effect of Twist on Staple Yarn Properties.
(i) As twist increases, yarn strength and yarn stiffness increases up to a point, level off, then begin to fall at very high twist levels.
(ii) Yarns with extremely high levels of twist are called “crepe yarns”; these yarns possess a high degree of torque.
(ii) Complex yarns give fancy effects in fabrics.
Ans: Complex (Fancy, Novelty) yarns:
(i) Complex yarns are made to create decorative effects in the fabrics into which they are woven.
(ii) Complex yarns are usually weaker than simple yarns.
(iii) Complex yarns are usually woven into the filling direction of the fabric.
(iv) Complex yarns usually exhibit more snagging and wear..
(iii) Complex yarns are uneven in their diameter
Ans: Novelty (fancy, complex) yarns- yarns that have a decorative effect; not uniform in size and appearance.
(iv) Thread is not the same as yarn.
Ans: Yarn is a long continuous length of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and rope-making.
Thread is a type of yarn intended for sewing by hand or machine.
Q. 3. Crossword puzzle:
Clue:
Down
1. Fibre good for undergarmets.
5. Strongest manmade fibre.
Across
2. Strong, finely twisted yarn.
3. Group of fibres.
4. Manmade cellulosic fibre.
Ans: 1. cotton.
2. thread.
3. yarn.
4. rayon.
5. nylon.
TERMINAL QUESTIONS
Q. 1. How will you define a yarn?
Ans: A continuous strand of textile fibres that may be composed of endless filaments or shorter fibres twisted or otherwise held together.
Q. 2. Explain the process of making yarns from staple fibres.
Ans: Yarn consists of several strands. of material twisted together. Each strand is in turn made of fibres, all shorter than the piece of yarn that they form. These short fibres are spun into longer filaments to make the yarn. Long continuous strands may only require additional twisting to make them into yarns. Sometimes they are put through an additional process called texturing.
Q. 3. Why are fabrics made from textured yarn more comfortable to wear?
Ans: (i) Fabrics made from flat continuous filament yarns show shine and are smooth with minimal surface friction.
(ii) Continuous filament yarns are often texturized, in order to produce fabrics with spun yarn aesthetics. Texturizing processes all increase yarn bulk, and most increase yarn stretch.
Characteristics Texturized Filaments:
• More absorbent.
• Better bulk, cover, elasticity.
• Not pill or shed.
Q. 4. Which additional properties make a yarn into a thread?
Ans: Continuous strand of fibres grouped or twisted together and used to construct textile fabrics. Yarns are made from both natural and synthetic fibres, in filament or staple form. Filament is very long fibre, including the natural fibre silk and the synthetic fibres. Most fibres that occur in nature are fairly short, or staple and synthetic fibres may be cut into short, uniform lengths to form staple. Spinning is the proces of drawing out and twisting a mass of cleaned, prepared fibres. Filament yarns generally require less twist than do staple yarns. More twist produces stronger yarn; low twist produces softer, shinier yarn. Two or more single strands may be twisted together to form ply yarn. Knitting yarns have less twist than weaving yarns. “Thread”, used for sewing, is a tightly twisted ply yarn. A yarn is a continuous strand made up of a number of fibres which are twisted together.
• fibres are created into yarns.
• yarns are then woven or knit into fabrics.
Thread: Machine sewing thread (of any fibre type) has too high a twist and therefore is too abrasive to be used on most natural fibre textiles, especially if they are old and/or already weakened. Hand sewing thread as thin as a single strand of hair is available in cotton, silk and wool (and in a wide variety of colours).
Difference between thread and yarn
The difference is not only in what both of these types are made out of, but mostly in the size. Yarn is thicker than thread. Each one has its own sizes. You sew with thread and you either knit or crochet with yarn. Yarn made from wool can be from sheep or alpaca or other fibres that can be spun. Yarn can be acrylic, wool, cotton, silk or a blend of these. It comes in various ply (meaning strands the more strands, the thicker the yarn). Thread is usually cotton, but can also be silk or a blend of both. It is used for sewing by hand or machine, embroidery or cross stitch. Thread is a tightly twisted strand of two or more ply of yarn that is circular when cut in cross section. It is used for hand sewing and in home sewing machines.
Sewing thread is distinguished from yarn by the fact that thread is used to sew together garments or other products, but yarn is thet collection of fibres used to weave or knit into a textile fabric, thread can be made of yarn, but yarn is not made of threads.
Q. 5. What kind of properties will you look for when you purchase “terewool fabric”?
Ans: Fabrics have observable properties.
Blends: You all must have heard of fabrics with names like terecot and cotswool. These are the names of mixed fabrics. Cotswool is a mixture of cotton and wool and terewool of wool and terene. Blends are made from more than one kind of fibres. At the yarn stage itself, two types of fibres are mixed, pulled out and twisted together to form the yarn. Check the fabric quality for these characteristics:
1. Grain: Grain is very important in fabric. Woven fabrics are “on-grain,” if the lengthwise and crosswise yarns are at right angles. Knit fabrics are “on-grain,” if the lengthwise rows of loops in the knit are straight. Fabrics must be “on-grain” so the clothes you make will hang straight and look right.
2. Wrinkle or crease resistant: Crush a corner of the fabric and hold it tightly for several seconds. Then look for wrinkles. Fabrics that wrinkle easily will require extra care.
3. Colourfastness: Rub the fabric against your skin or a light coloured fabric. Check to see if colour rubbed off.
4. Flaws in construction and dyeing: As fabric is unrolled from the bolt, look closely for obvious flaws in construction. Also, check for fading. Sometimes fading will occur along the fold or where the fabric has been exposed to sunlight.
5. Odour: Although chemical finishing odours usually are removed by the first laundering, it is wise to avoid fabrics with strong odours.
6. Care requirements: Read the information on the end of the fabric bolt. It should tell you what fibre the fabric is made from, the width of the fabric, the price, if the fabric will shrink, if there are special finishes and how to care for it.
7. Finishes: A finish is any process the fabric goes through (after it is woven) to give it additional characteristics that will make it wear longer, be easier to care for or add beauty. You can’t identify a finish by looking at the fabric or feeling it. The label must tell you the kind of finish.
8. Finishes, like fibres, have trademarks. You may find trademarks on the label instead of the general classifications of finishes. Some finishes you want to look for on the labels of the clothes you buy are given.
