Edexcel IGCSE Physics topic guide
Solids, liquids and gases questions
Use the particle model to explain heating, changes of state and gas pressure, then apply the relationships behind the observations.
Solids, liquids and gases topic overview
Solids, liquids and gases links particle behaviour to density, pressure, changes of state, thermal energy and gas laws.
Move between the particle model and measurable quantities carefully, convert temperatures to kelvin for gas laws, and keep volume and pressure units consistent.
Question types in solids, liquids and gases
- Density, pressure, specific heat capacity and gas-law calculations.
- Particle-model explanations for states, pressure, temperature and changes of state.
- Heating and cooling graph interpretation, including constant-temperature regions.
- Practical methods for density and specific heat capacity measurements.
Solids, liquids and gases subtopics
Choose a subtopic for its syllabus points, answering guidance and worked exam questions.
5.a Units
Temperature, density and pressure units, plus reading quantities from graphs.
5.b Density and pressure
Mass and volume, force and area, and pressure at different depths in liquids.
5.c Change of state
Particle energy, heating, specific heat capacity, melting, boiling and evaporation.
5.d Ideal gas molecules
Random particle motion, gas pressure, absolute temperature and gas laws.