Reducing Unwanted Energy Transfers

• What is always transferred to energy stores that are not useful?

  Some energy
• Why is it important to reduce unwanted energy transfers?

  To maximize energy in useful energy stores
• What are some methods to reduce unwanted energy transfers?

  • Thermal insulation
  • Loft insulation
  • Cavity wall insulation
  • Draught-proofing
  • Hot water tank jacket
  • Double glazing
• How do thicker walls affect the rate of energy transfer?

  They slow the rate of energy transfer
• What role does thermal conductivity play in energy transfer?

  Lower thermal conductivity slows energy transfer
• What is loft insulation made of?

  Fibreglass
• How does cavity wall insulation work?

  It fills the air gap to reduce energy transfer
• What does double glazing prevent?

  Energy transfer by conduction through windows
• How does draught-proofing reduce energy transfer?

  It stops draughts blowing in and out
• What does a hot water tank jacket do?

  Reduces energy transfer by conduction
• How do thick curtains help reduce energy loss?

  They create an air gap to stop convection
• What is the procedure to investigate thermal insulators?

  1. Boil water and pour into a container
  2. Measure initial temperature
  3. Seal and wait for five minutes
  4. Measure final temperature
  5. Wrap container in different insulating materials
  6. Compare temperature differences
• What should you find when wrapping a container in insulating materials?

  Temperature difference is reduced
• How does the thickness of insulating material affect temperature change?

  Thicker material results in smaller temperature change
• What is a risk assessment needed for in experiments?

  To identify potential hazards
• How can you prevent water temperature from decreasing too much during measurement?

  Use a cardboard disk with a cut
• What is the purpose of lubrication?

  To reduce friction between moving objects
• How do lubricants work?

  They flow between objects to reduce friction
• Where is lubrication commonly used?

  On axles in cars and turbines
• What are the effects of air resistance on falling objects?

  • Transfers energy from kinetic to thermal energy
  • Causes energy dissipation in the surroundings
• What are the benefits of streamlining in reducing energy loss?

  • Reduces air resistance
  • Increases efficiency of moving objects