6.1.2 conservation + dissipation of energy

• What can energy be transferred as in a system?


  Energy can be transferred usefully, stored, or dissipated.
• What happens to the total energy in a closed system during energy transfers?


  There is no net change to the total energy.
• How is energy often described when it is dissipated in a system?


  It is often described as being 'wasted'.
• What are some ways to reduce unwanted energy transfers?

  • Lubrication
  • Use of thermal insulation
• How does thermal conductivity affect energy transfer?


  The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction.
• How does the thickness and thermal conductivity of walls affect the rate of cooling of a building?


  The rate of cooling is affected by both the thickness and thermal conductivity of its walls.
• What is the required practical activity related to thermal insulation?


  • Investigate the effectiveness of different materials as thermal insulators.
  • Factors affecting thermal insulation properties of a material.
• What is the equation for calculating energy efficiency?

  Efficiency = useful output energy transfer / total input energy transfer.
• What is another equation for calculating efficiency?


  Efficiency = useful power output / total power input.
• What should students be able to describe to increase the efficiency of energy transfer?


  Students should be able to describe ways to increase the efficiency of an intended energy transfer.
• In what forms may efficiency values be required to be calculated or used?


  Efficiency values may be required as a decimal or as a percentage.
• What are the main energy resources available for use on Earth?

  Fossil fuels, nuclear fuel, bio-fuel, wind, hydro-electricity, geothermal, tides, the Sun, and water waves
• What defines a renewable energy resource?


  A renewable energy resource is one that is being or can be replenished as it is used
• What are some uses of energy resources?


  Transport, electricity generation, and heating
• What should students be able to do regarding energy sources?


  • Describe the main energy sources available
  • Distinguish between renewable and non-renewable resources
  • Compare uses of different energy resources
  • Understand reliability of energy resources
  • Describe environmental impacts of energy resources
  • Explain patterns and trends in energy resource use
• What environmental issues should students consider regarding energy resources?


  • Identify environmental issues arising from energy resource use
  • Understand that science can identify issues but may lack power to address them
  • Consider political, social, ethical, or economic factors affecting solutions