Practical: investigate the specific heat capacity of a substance
3 marks · NormalA student is recording temperature readings during a specific heat capacity experiment and finds that the measured specific heat capacity is much lower than the accepted value for the material.
State and explain two possible experimental errors that could cause the measured value to be too low.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Must show: Mentions two valid errors, e.g. not all energy goes to material (energy lost to surroundings); poor insulation; thermometer not placed properly; energy escapes; block not allowed to reach equilibrium, Explanation links error to value being too low
Show mark scheme and worked solution
Marking points
B1 · 1 mark · First valid experimental error correctly stated and explained
B2 · 1 mark · Second valid error correctly stated and explained
B3 · 1 mark · Both explanations clearly link the error to a lower measured value of specific heat capacity
Worked solution
1. Heat loss to the surroundings: If the material is not well insulated, some supplied energy escapes to the surroundings instead of heating the block. This means the calculated energy input is larger than the energy actually used, so calculated c is too low.
2. Incorrect thermometer placement: If the thermometer is not inserted correctly or not in good contact with the block, it might read a smaller temperature rise than actually occurs, leading to an underestimation of Δθ and therefore a lower c.