If the temperature of the system increases, the increase in temperature depends on the mass of the substance heated, the type of material and the energy input to the system.
BEEZYREVISOR
GCSE Physics Revision
Learn it. Recall it. Revise it.
GCSE Physics revision
Temperature changes in a system and specific heat capacity
Internal energy and energy transfers
Your specification
AQA student objectives
Learning pathway
All · Most · Some
Apply the specified scientific knowledge of temperature changes in a system and specific heat capacity to a relevant example.
Analyse an unfamiliar example of temperature changes in a system and specific heat capacity using the specified scientific ideas.
Revision summary
Key knowledge
Read on screen, then print for Cornell-style active revision.
Factors Affecting Temperature Change
- The temperature change of a substance depends on three key factors: the mass of the substance, the type of material, and the amount of energy input.
- As the mass of a substance increases, the number of particles increases, making it harder to raise the temperature.
- Different materials heat up at different rates — conductors are relatively easy to heat, whilst insulators are more difficult to heat.
- As the amount of energy input increases, there is more energy available to be converted into kinetic, potential, and thermal energies, raising the temperature more.
The Thermal Energy Equation
- The change in thermal energy can be calculated using the formula: Δ E = m × c × Δθ, where m is mass, c is specific heat capacity, and Δθ is the temperature change.
- The unit for change in thermal energy is joules (J), mass is in kilograms (kg), and temperature change is in degrees Celsius (°C).
- Specific heat capacity has the unit joules per kilogram per degree Celsius (J/kg/°C).
Worked Example: Calculating Thermal Energy
- To find the change in thermal energy for 2 kg of iron (specific heat capacity = 450 J/kg/°C) heated by 5°C, substitute into the equation: Δ E = 2 × 450 × 5.
- The correct answer is Δ E = 4{,}500 J, showing all working clearly is essential to gain full marks in an exam.
- Even without the correct final answer, marks can be awarded for correctly writing out the substitution, such as 2 × 450 × 5.
Definition of Specific Heat Capacity
- Specific heat capacity is defined as the amount of energy required to raise the temperature of one kilogram of a substance by one degree Celsius.
- Water has a specific heat capacity of 4,200 J/kg/°C, meaning it requires 4,200 joules to raise 1 kg of water by 1°C.
- Different substances have different specific heat capacities, which is why some materials heat up or cool down more quickly than others.
Exam Tips & AQA Specification
- AQA exam questions may ask you to discuss the factors affecting the temperature change of a substance and apply this to a real-life context.
- Always write out the full equation, substitute values clearly, and include units in your final answer to maximise marks.
- This topic links to the broader AQA specification on internal energy and energy transfers, so understanding the connections between concepts is important.