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CAIE IGCSE Physics 2.1.2 Particle model Question Bank

Practise using the particle model to explain states, temperature, Brownian motion, gas pressure and changes in particle spacing.

Syllabus
2026–2028
Course
Physics 0625

Exam points

  • compare particle arrangement and motion in solids, liquids and gases using diagrams or tables
  • explain gas pressure from particles colliding with walls and changing momentum
  • link random motion of pollen or smoke specks to collisions with moving molecules

Covered syllabus points

2.1.2.1—Particle structure of solids, liquids2.1.2.2—Relationship between the motion of2.1.2.3—Pressure and the changes in pressure2.1.2.4—Random motion of microscopic particles2.1.2.5—And explain this motion (sometimes2.1.2.6—Forces and distances between particles2.1.2.7—Pressure and the changes in pressure2.1.2.8—Microscopic particles may be moved by

2.1.2 Particle model question 1

[Maximum number: 1]

The molecules of most liquids are, on average, slightly further apart than the molecules of a solid.

State one other difference between the molecular structures of a solid and a liquid.

2.1.2 Particle model question 2

[Maximum number: 1]

The lowest possible temperature is zero kelvin ( 0 K ).

State the name of this lowest possible temperature.

2.1.2 Particle model question 3

[Maximum number: 4]

Fig. 4.1 shows a pressure cooker on an electric heating element. The cooker has a tight-fitting lid.

Fig. 4.1

Fig. 4.1

As the water is heated, the pressure of the gas inside the cooker increases. Explain this increase in pressure in terms of particles.

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