Experiment 9.1:
Aim: To study the uses of different materials as heat insulators.
Problem statement: Which is a good heat insulator, cotton, felt or aluminium foil?
Hypothesis: Cotton and felt are good heat insulators.
Variables:
(a) Constant variable: Volume of water in the flat-bottom flasks
(b) Manipulated variable: Types of insulators
(c) Responding variable: Final temperature
Materials: Cotton, felt, aluminium foil and boiling water
Apparatus: Flat-bottom flask, rubber stopper, thermometer and stopwatch
Procedure:
1. Prepare four flat-bottom flasks as shown in Figure 9.8.
2. Record the initial temperature of each flask.
3. Record the final temperature of each flask after 10 minutes.
Observation:
Conclusion:
Is the hypothesis accepted? Give your reasons.
Questions
1. State an inference for the observation made for flask N.
2. What is the use of flask K?
Answer:
1. The temperature of water decreases the most in flat-bottom flask N because aluminium is not a good heat insulator and transfers heat from the water faster.
2. Flat-bottom flask K is used as a control to be compared with the result of the experiment.
Aim: To study the uses of different materials as heat insulators.
Problem statement: Which is a good heat insulator, cotton, felt or aluminium foil?
Hypothesis: Cotton and felt are good heat insulators.
Variables:
(a) Constant variable: Volume of water in the flat-bottom flasks
(b) Manipulated variable: Types of insulators
(c) Responding variable: Final temperature
Materials: Cotton, felt, aluminium foil and boiling water
Apparatus: Flat-bottom flask, rubber stopper, thermometer and stopwatch
Procedure:
1. Prepare four flat-bottom flasks as shown in Figure 9.8.
2. Record the initial temperature of each flask.
3. Record the final temperature of each flask after 10 minutes.
Observation:
Conclusion:
Is the hypothesis accepted? Give your reasons.
Questions
1. State an inference for the observation made for flask N.
2. What is the use of flask K?
Answer:
1. The temperature of water decreases the most in flat-bottom flask N because aluminium is not a good heat insulator and transfers heat from the water faster.
2. Flat-bottom flask K is used as a control to be compared with the result of the experiment.