Kinetic particle model of matter

States, particle explanations, temperature, internal energy and constant-temperature changes of state.

  • SEC G2 Science Physics component 2027
Learning goals
  • Compare physical properties of solids, liquids and gases
  • Explain state properties using particle arrangement, motion, forces and separation
  • Relate temperature rise to increased average kinetic energy of particles
  • describe internal energy as an energy store that is made up of the total kinetic energy associated with the random motion of the particles and the total potential energy between the particles in the system
  • describe melting/solidification and boiling/condensation as processes of energy transfer without a change in temperature

G2 Science (Physics) · Topic 6

Read the complete lesson from top to bottom first. Pause for its examples and independent questions, then use a short topic check to decide what to practise again.

Start topic

Before you begin

Build the idea in order

  1. Particle arrangement
  2. Particle motion
  3. Temperature and internal energy
  4. Changes of state

Lessons

Check your understanding

What to remember

  • Explain states using arrangement, motion, separation and forces.
  • Gases compress because particles are far apart.
  • Temperature tracks average particle kinetic energy.
  • Internal energy totals microscopic kinetic and potential energy.
  • At constant-temperature state change, potential energy changes while average kinetic energy stays constant.

Topic and syllabus information

Kinetic particle model of matter is Topic 6 in K223 / K224 Physics component · 2027.

The lesson stays within G2 depth and includes the explanations, examples and practice needed for this topic.

Reviewed 9 Aug 2026

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Course and syllabus information
Course
SEC G2 Science Physics component
Edition
SEC G2 Science Physics component 2027