Australian Content descriptors - Year 7 the particle and kinetic theories of matter can be used to describe the arrangement and motion of particles in a substance, including the attraction between particles, and to explain the properties and behaviour of substances, including melting point, boiling point, density, compressibility, gas pressure, viscosity, diffusion, sublimation, and expansion and contraction (VC2S8U05). use particle theory to describe the arrangement of particles in a substance,