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GCSE Physics Required Practical: Investigating Thermal Insulators

Key Stage 4


Investigate the effectiveness of different thermal insulators on reducing an energy transfer by heating.



Independent Variable: Insulating material.
Dependent Variable: The temperature decrease of water after a given time.
Control Variables: The volume of water used. The initial temperature of the water. The time taken between measurements. Thickness of the insulating material.


A diagram of the apparatus used in an experiment to compare the effectiveness of different thermal insulators.
  1. Measure 100ml of hot water (around 50°C) using a measuring cylinder.
  2. Fill a can with hot water
  3. Place a thermometer in the water and wait until the temperature reaches 40°C.
  4. Begin a stopwatch when the temperature is 40°C then read the temperature every 30 seconds for 5 minutes.
  5. Repeat steps 1-3 with a can covered each type of insulating material.
  6. Plot a graph with temperature on the y-axis and time on the x-axis plotting the results for each insulating material on the same graph.

Improving Accuracy

Place the cans on a heatproof mat to reduce the thermal energy lost to the table surface by conduction.
Place a lid over the cans to reduce the thermal energy lost to the air by evaporation.
Complete the experiments with different insulators simultaneously so that a change in the temperature of the laboratory does not affect the results.
Place the measuring cylinder on a flat, level surface and read it from eye level to get an accurate reading of the volume of water.
A diagram including apparatus used improve the accuracy of an experiment to compare the effectiveness of different thermal insulators.

Improving Precision

Ensure the same amount of water (Control Variable) is used in each container to reduce the random error in repeat readings.