Changes in State

• Melting


  • temperature of solid substance increases until it reaches its melting point
  • Forces of attraction between the particles in the solid are overcome by the motion of the particles
  • melting occurs, the substance changes state from solid to liquid
  • temperature remains constant during melting
• Boiling


  • Temperature of the liquid substance increases until it reaches its boiling point
  • forces of attraction between the particles in the liquid are overcome by the motion of the particles
  • boiling occurs, the substance changes from a liquid to a gas
  • temperature remains constant during boiling
• Condensation


  • temperature of the gaseous substance decreases until it reaches its condensation point
  • forces of attraction between the gas particles increase, condensation occurs and the substance changes from gas to liquid
  • temperature remains constant as condensation occurs
• Freezing

  • temperature of the liquid decreases until it reaches its freezing point
  • forces of attraction between the particles in liquid increase further, the particles become closer and are arranged in a more orderly manner
  • freezing occurs, substance changes from liquid to solid
  • temperature remains constant throughout freezing