Required Practical - Investigating Insulation
Physics: AQA GCSE Higher, topic 1.2.5
Investigating Different Insulating Materials
The aim of this experiment is to investigate how well different materials reduce heat loss from a container of hot water, and identify which material is the most effective thermal insulator.
Apparatus
- Two beakers (one large, one small)
- Kettle or hot water source
- Stopwatch
- Thermometer
- Measuring cylinder
- Cardboard lid with a hole for the thermometer
- Various insulating materials (e.g. bubble wrap, cotton wool, foil, felt)
Variables
- Independent variable:
- Type of insulating material
- Dependent variable:
- Temperature change over time
- Control variables:
- Starting temperature, volume of water, type of beakers, room temperature
Method
- Place a smaller beaker inside a larger beaker.
- Measure a fixed volume of hot water and pour it into the smaller beaker.
- Cover the beaker with the cardboard lid and insert a thermometer through the hole so it rests in the hot water.
- Record the starting temperature of the water.
- Start the stopwatch and record the temperature every two minutes for a total of 20 minutes.
- Repeat the experiment using different insulating materials in the space between the two beakers.
Results
- Create a table showing temperature readings at each time interval.
- Use a line graph to plot temperature (°C) on the y-axis and time (minutes) on the x-axis.
- Draw a smooth curve for each material on the same graph to show how the temperature changes over time.
- Compare the cooling curves:
- The line that drops the slowest indicates the best insulator.
- The line that drops quickly represents a poor insulator.
Conclusion
- When the water is very hot, the temperature difference between the beaker and the air is large, so heat is lost quickly.
- Heat transfer is reduced when materials trap air, as air is a poor conductor of heat.
- The material that kept the water hottest for the longest time is the most effective thermal insulator.
Safety and Precautions
- Hot water may cause burns or scalds:
- Pour carefully and never overfill the beaker.
- Beaker tipping over:
- Keep equipments away from edges and perform the experiment while standing.
- Steam from kettle:
- Possible burns allow water to cool slightly before pouring. Do not lean directly over the beaker
Test yourself on Required Practical - Investigating Insulation
What does a slowly falling line on the cooling curve indicate?