Describe matter with particles
A solid has particles in fixed positions, a liquid has particles that move past one another, and a gas has particles far apart moving randomly. The particles themselves do not expand when a substance is heated.
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AQA GCSE Particle model of matter
AQA GCSE Particle model of matter Revision
Use a particle model to explain density, changes of state, internal energy and gas pressure. Keep particle spacing, particle motion and energy separate.
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Use the resource cards below to revise one idea at a time. Each page includes worked examples, mini quizzes, practice questions, exam language and a visual or simulation when it adds learning value.
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Use this overview to find the part of the topic that needs attention; the focused guides below teach and assess each idea in depth.
Link temperature to energy
Heating changes the internal energy of a system. During a change of state, energy changes the separation of particles while the temperature remains constant for a pure substance.
Explain pressure with collisions
Gas pressure comes from particles colliding with the container walls. Increasing temperature increases average kinetic energy; compressing a fixed mass increases collision frequency.
Focused revision
Choose one idea at a time
Each guide combines explanation, a diagnostic check, misconception repair, worked examples and exam-style practice.
PM-01
Density and Particle Arrangement
Density compares mass in an equal volume. A larger object need not be denser: its mass and volume may rise in the same ratio.
PM-02
Internal Energy and Heating Curves
A temperature rise and a change of state both increase internal energy, but they require different equations and different particle explanations.
PM-03
Gas Pressure and Temperature
Gas pressure comes from repeated molecular impacts on a surface. Keep the amount of gas, volume and temperature conditions explicit before predicting a change.
PM-04
Density Required Practical
The density practical includes regular solids, irregular solids and liquids. Each needs an appropriate volume measurement and a mass that excludes its container.
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AQA GCSE Physics Density Calculations and Required Practical WorksheetFree printable questions and a separate solutions PDF.
AQA GCSE Physics Particle Model, Changes of State and Specific Latent Heat WorksheetFree printable questions and a separate solutions PDF.
AQA GCSE Physics Gas Pressure Volume and Boyle Law WorksheetFree printable questions and a separate solutions PDF.
AQA GCSE Physics Heating and Cooling Curves Mixed Calculations WorksheetFree printable questions and a separate solutions PDF.
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