Synthetic Fibres and Plastics Activity Solution Chapter 3 Class 8 Science
Activity 3.1
Activity 3.1 asks us to gauze the strength of various fibres viz. Cotton, wool, silk, nylon.
Procedure:
- Extract fibres from the fabric of the aforementioned type.
- pull out the fibre of equal thickness and length.
- Add fibre to the stand one by one and check with the various weights.
- Note down the highest weight handled in the sheet
Observation:
Wool holds the lowest weight while nylon shows it is strongest. The tensile strength of the following four in ascending order is:
Wool<Silk<Cotton<Nylon.
Note: Strength depends on the thickness of the wire and its length. If you take longer thin fibre the weight required to break the fibre will be lesser and vice-a-versa.
Extend of weighing of the following material with reference of 1kg will be in the order of :
0.1kg<0.15kg<0.3kg<0.8kg (approx averages)
Explanation:
Different fibres show different properties. These properties depend on their polymer. If the polymer is more stable its threads will be stronger. In the experiment, we get that wool and silk are much fragile than cotton and nylon is the strongest.
Application:
Nylons are very strong. So, they found use in parachute ropes and ropes of rock climbing.
Activity 3.2
Activity 3.2 asks us to soak artificial and natural fabric pieces in water and check which absorbs water most.
Observation:
Natural fabrics like wool, cotton, silk etc absorb more water than nylon and polyester.
Application:
Nylons and plastics are more durable on the exposure to water. So, they form long-lasting materials like electric wire, toys, many types of equipment and utensils etc.
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Activity Solution Synthetic Fibres and Plastics Chapter 3 Class 8 Science
Ref: NCERT ch3
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