Heating and Cooling Graphs

• What should you be able to do by the end of the video?

  Interpret heating and cooling graphs
• What is internal energy?

  Energy stored inside a system by particles
• What types of energy are included in internal energy?

  Kinetic and potential energy of particles
• What does potential energy in particles depend on?

  Forces between particles and atomic bonds
• What happens to a solid substance when it is gradually heated?

  • Temperature rises as energy increases
  • At melting point, it changes to liquid
  • Energy weakens forces of attraction
• What is the term for the energy needed for a substance to change state?

  Latent heat
• What happens to internal energy during a change of state?

  It increases, but temperature remains constant
• How can you find the melting point from a heating graph?

  By reading off the horizontal line
• What occurs when all of the solid has melted?

  The temperature starts to rise again
• What is the term for the point where a substance boils?

  Boiling point
• What happens to the temperature during boiling?

  It stops increasing and becomes horizontal
• What does a cooling graph show when cooling a gas?

  • Temperature decreases as energy is lost
  • Change of state occurs at condensation
  • Further cooling leads to freezing
• What is the term for the change from gas to liquid?

  Condensation
• What is the term for the change from liquid to solid?

  Freezing
• Where can you find questions on heating and cooling graphs?

  • In the revision workbook
  • Available through a provided link
• What should you be able to do after watching the video?

  Interpret heating and cooling graphs