Particle model
This lesson builds specific heat capacity and specific latent heat for GCSE Physics.
Use the core lesson first, then match the exam-board guidance to your school route. Many pupils meet this content through Combined Science as well as Separate Physics.
What you will learn
Exam-board fit
Exact paper labels and specification-point numbering vary by board and cohort, so match this lesson to your school route before using past-paper questions.
Heating data supplied on this page
Use water, metal block and melting examples to practise choosing between temperature-change and change-of-state equations.
Clear explanation
Specific heat capacity tells you how much energy is needed to raise 1 kg of a substance by 1 degree Celsius.
Specific latent heat tells you how much energy is needed to change the state of 1 kg of a substance without changing temperature.
The key decision is whether temperature changes. If temperature changes, use the specific heat capacity equation. If state changes at constant temperature, use latent heat.
Key graph
Worked examples
Heating water
2 kg of water is heated by 10 degrees Celsius. The specific heat capacity is 4200 J/kg degrees Celsius.
energy = mass x specific heat capacity x temperature change
energy = 2 x 4200 x 10 = 84 000
Quick checks
Choose an answer, then check your thinking.
1. Which equation is used when temperature changes but state does not?
2. What happens to temperature during melting at the melting point?
Practice questions
Question 1
A 0.5 kg block with specific heat capacity 900 J/kg degrees Celsius warms by 20 degrees Celsius. Calculate energy transferred.
Reveal answer and marking guidance
Answer: 9000 J.
Marking: Credit E = m c delta theta = 0.5 x 900 x 20 = 9000 J.
Question 2
Calculate energy needed to melt 0.2 kg of a substance with latent heat 100 000 J/kg.
Reveal answer and marking guidance
Answer: 20 000 J.
Marking: Credit E = m L = 0.2 x 100 000 = 20 000 J.
Question 3
Why is latent heat not calculated using temperature change?
Reveal answer and marking guidance
Answer: During a change of state, temperature stays constant while energy changes particle arrangement.
Marking: Credit state change and constant temperature.
Question 4
On a heating graph, what does a flat section usually show?
Reveal answer and marking guidance
Answer: A change of state.
Marking: Credit melting or boiling at constant temperature.
Exam practice ladder
Answers and marking guidance
The exact practice answers are hidden under each question so you can try first. For this lesson, marks come from using the correct physics model, choosing the right equation where needed, keeping units with values, and explaining changes with precise words such as transfer, resultant force, acceleration, evidence and uncertainty.
Common mistakes
- Using latent heat when temperature changes.
- Forgetting mass must be in kg for standard units.
- Treating degrees Celsius as the energy unit.
- Ignoring flat sections of heating graphs.
Exam-board guidance
All supported routes assess the core physics idea, but they may group topics, practicals and paper wording differently.
AQA GCSE Physics
AQA GCSE Physics: use this lesson for specific heat capacity and specific latent heat, then check whether your class is taking Separate Physics or Combined Science.
OCR GCSE Physics
OCR GCSE Physics: the core physics idea is shared, but Gateway and Twenty First Century may organise questions differently.
Pearson Edexcel GCSE Physics
Pearson Edexcel GCSE Physics: practise the concept, the equation use and the practical language because questions often connect them.
Eduqas GCSE Physics
Eduqas GCSE Physics: learn the core explanation and practise applying it to unfamiliar contexts, data and practical questions.
WJEC Wales
WJEC Wales: check whether your class is using the current GCSE Physics route or a newer science route, then use this lesson for the shared physics idea.
CCEA GCSE Physics
CCEA GCSE Physics: connect the idea to your unit and remember that practical skills are assessed directly.
Extension challenge
Write two heating questions with the same mass, one using specific heat capacity and one using latent heat.
Reveal answer
Example answer: A strong extension response names the physics model, uses accurate units and explains why the evidence supports the conclusion.
Next lesson
Next, continue with Distance-Time and Velocity-Time Graphs.