Question 4:
A Form 4 student found his bicycle tyre punctured on his way home from school. Then, he went to the workshop to repair his tyres. When the mechanic was repairing the tyre, the student discovered that the rubber tube of the tyre he was holding has different elasticity compared to the coagulated latex in his school laboratory.
Answer:
(a)
Aim:
To study the elasticity of natural and vulcanised rubber
(e)
Procedure:
1. Record the initial length of the rubber sheet.
2. Arrange the apparatus and materials as shown in the figure.
3. Hang a 50 g weight at the bottom of the natural rubber sheet and remove it after 1 minute.
4. Observe and record the length of the rubber sheet.
5. Repeat steps 1 to 4 by replacing the natural rubber sheet with a vulcanised rubber sheet.
(g) Tabulation of data:
A Form 4 student found his bicycle tyre punctured on his way home from school. Then, he went to the workshop to repair his tyres. When the mechanic was repairing the tyre, the student discovered that the rubber tube of the tyre he was holding has different elasticity compared to the coagulated latex in his school laboratory.
Referring to the above statement, plan an experiment in the laboratory to study the elasticity of the two types of rubber. Your plan should include the following:
(a) aim
(b) hypothesis
(c) variables
(d) materials and apparatus
(e) procedure
(f) setup of apparatus
(g) tabulation of data
Answer:
(a)
Aim:
To study the elasticity of natural and vulcanised rubber
(b)
Hypothesis:
When vulcanised rubber is used, change in the length of the rubber sheet does not happen
(c)
Variables:
• Manipulated: Type of rubber sheet
• Responding: Change in the length of rubber
• Constant: Mass of weight/length and the original thickness of the rubber
(d)
Materials and apparatus:
Natural rubber sheet, vulcanised rubber sheet, weight 50 g, retort stand and clamps
(e)
Procedure:
1. Record the initial length of the rubber sheet.
2. Arrange the apparatus and materials as shown in the figure.
3. Hang a 50 g weight at the bottom of the natural rubber sheet and remove it after 1 minute.
4. Observe and record the length of the rubber sheet.
5. Repeat steps 1 to 4 by replacing the natural rubber sheet with a vulcanised rubber sheet.
(f) Setup of apparatus:
(g) Tabulation of data: