Fabrics Around Us — NCERT Solutions

Given: We need to state three properties of each of the listed fibres.

(i) Cotton

1. Absorbency: Cotton is highly absorbent and can absorb moisture quickly, making it comfortable to wear in hot and humid weather.
2. Strength: Cotton is a strong fibre; it becomes even stronger when wet.
3. Heat Conductivity: Cotton is a good conductor of heat, which keeps the body cool. It can withstand high temperatures and can be boiled and ironed at high heat.

(ii) Linen

1. Strength: Linen is one of the strongest natural fibres — stronger than cotton — and becomes stronger when wet.
2. Smoothness and Lustre: Linen has a natural smooth surface with a slight lustre, giving it a crisp appearance.
3. Low Elasticity: Linen has very low elasticity and creases easily; it does not recover well from wrinkles.

(iii) Wool

1. Warmth / Insulation: Wool is an excellent insulator due to its natural crimp, which traps air and retains body heat.
2. Elasticity and Resilience: Wool has good elasticity and resilience — it can stretch and return to its original shape, resisting wrinkles.
3. Absorbency: Wool can absorb a large amount of moisture (up to 30% of its weight) without feeling wet, making it comfortable to wear.

(iv) Silk

1. Lustre: Silk has a natural, brilliant lustre due to its triangular prism-like fibre structure that reflects light.
2. Strength: Silk is the strongest natural fibre; however, its strength decreases when wet.
3. Draping Quality: Silk has excellent draping quality — it falls gracefully and clings softly to the body, making it ideal for elegant garments.

(v) Rayon

1. Absorbency: Rayon is highly absorbent, even more than cotton, making it comfortable in warm weather.
2. Softness and Drape: Rayon is soft, smooth, and has good draping quality, similar to silk in appearance.
3. Weakness when Wet: Rayon loses significant strength when wet and must be handled carefully during washing.

(vi) Nylon

1. High Strength and Durability: Nylon is one of the strongest textile fibres and is highly resistant to abrasion and wear.
2. Elasticity: Nylon has excellent elasticity and recovers well from stretching, making it suitable for hosiery and sportswear.
3. Low Absorbency / Quick Drying: Nylon absorbs very little moisture and dries quickly; however, this makes it less comfortable in hot weather.

(vii) Acrylic

1. Wool-like Warmth: Acrylic is soft, lightweight, and warm, making it an excellent substitute for wool in blankets, sweaters, and children's wear.
2. High Elongation with Elastic Recovery: Acrylic fibres have high elongation (can be stretched considerably) and good elastic recovery.
3. Moderate Strength: The strength of acrylic is not very high and is similar to that of cotton; it is less strong than nylon or polyester.

Conclusion: Each fibre has unique properties that determine its suitability for specific end uses in clothing, home furnishings, and industrial applications.

Theme: Fabrics Around Us

Objective: To identify and record the fabrics and apparel used by oneself and observed in surroundings throughout a day.

Procedure:
Choose a specific day and carefully observe all the fabric-based products you use or come in contact with. Record them in the following table:

(Students should fill in their own observations based on their actual day.)

Group Activity: Form groups of 4–5 students, pool all observations, and discuss the variety of fabrics used in school and at home.

Objective: To analyse why a particular fabric is chosen for a specific product.

Analysis of Suitability of Fabrics to Products:

Conclusion: The selection of fabric for any product depends on the properties required — such as absorbency, strength, warmth, elasticity, or appearance. Understanding fabric properties helps in making wise and informed choices as a consumer.

Theme: Thermal property and inflammability of fabrics

Objective: To identify the fibre content of various fabric samples by observing their burning behaviour, and to understand the inflammability of different fabrics for consumer safety.

Materials Required:

• Narrow strips of fabric samples ($\frac{1}{2}$ cm $\times$ 5 cm each) — cotton, wool, silk, rayon, nylon, polyester, acrylic
• Forceps or tongs
• Burning candle or spirit lamp (low flame)

Procedure:

1. Cut a narrow strip of each fabric sample measuring $\frac{1}{2}$ cm $\times$ 5 cm.
2. Hold the strip firmly with forceps or tongs.
3. Bring the strip slowly near the low flame of a candle or spirit lamp and observe its behaviour.
4. Place the strip in the flame and observe.
5. Remove the strip from the flame and observe whether it continues to burn or self-extinguishes.
6. Note the odour produced and examine the residue (ash or bead).
7. Repeat for all fabric samples and record observations.

Precaution: Perform this experiment on a very low flame of a candle or spirit lamp under the supervision of a teacher only.

Observation Table:

(Students should fill in their own observations based on the actual experiment conducted.)

Key Inferences:

1. Natural cellulosic fibres (Cotton, Linen, Rayon): Burn quickly, smell like burning paper, and leave a light ash or fluffy residue. They do not self-extinguish — they are flammable and require care near open flames.

2. Natural protein fibres (Wool, Silk): Curl away from flame, burn slowly, smell like burning hair, and are self-extinguishing. They are relatively safer near flames.

3. Synthetic fibres (Nylon, Polyester, Acrylic): Shrink or melt near flame, produce acrid or plastic-like odour, and leave a hard bead as residue. They can cause serious burns as the melted fibre sticks to skin.

Conclusion:
The burning test is a simple and effective method to identify the fibre content of a fabric. It also highlights the importance of fabric inflammability for consumer safety — especially for children's clothing and nightwear, where flame-resistant fabrics should be preferred. Protein fibres (wool, silk) are the safest near flames as they are self-extinguishing, while synthetic fibres pose a risk of melting and sticking to the skin.