Solids, liquids and gases

• The kinetic theory


  The use of the arrangement and movement of particles to describe solids, liquids and gases
• Solids

  • close together
  • regular pattern
  • vibrate on the spot
• Liquid

  • close together
  • random arrangement
  • move around each other
• Gas

  • far apart
  • random arrangement
  • move quickly in all directions
• Solids

  • have a shape and do not flow - the particles only vibrate around a fixed point and do not move from place to place
  • cannot be squashed - the particles are touching
• Liquids

  • flow and adopt the shape of the container - the particles can roll over each other because the bonds between them are not strong enough to keep them in a fixed position
  • cannot be squashed - the particles are touching
• Gases

  • spread out to fill their container - the particles are moving quickly in all directions
  • can be squashed - there are large spaces between the particles
• Limitations of the particle theory


  Particles are hard round spheres like marbles that do not make and break new bonds when they touch. We have to imagine these bonds forming and breaking even though we do not see this when using marbles to show the difference between solids, liquids and gases.