Specific heat capacity — required practical

AQA GCSE Physics

Determine the specific heat capacity of a material (e.g. a metal block).

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Method

  1. Measure the mass of the block; place a heater and thermometer into the block’s holes (add insulation).
  2. Record the starting temperature, switch on the heater and start timing.
  3. Measure the energy transferred (using a joulemeter, or power × time) and the temperature rise.

Variables

  • Independent variable: Energy transferred to the block
  • Dependent variable: Temperature of the block
  • Control variables: Mass of block, material, insulation

Results & analysis

Use E = m c Δθ, so c = E ÷ (m × Δθ). Plotting energy against temperature gives a straight line whose gradient = m × c.

Risk assessment

  • The block and heater get hot — allow to cool; keep water away from electrics.

Improving accuracy & reliability

  • Insulate the block to reduce heat loss to the surroundings.
  • Use a lid/lagging; a little oil in the thermometer hole improves thermal contact.
Exam tip: The main systematic error is heat lost to the surroundings, which makes the measured value too high — insulation reduces it.

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