P2 Energy Transfer by Heating

• What does thermal conductivity indicate about a material?

  How quickly energy is transmitted through it
• How can you test the thermal conductivity of metals?

  Using rods of equal diameter and length
• What happens to the wax on the rod during the thermal conductivity test?

  The faster it melts, the higher the conductivity
• What factors affect the rate of heat loss from buildings?

  1. Thickness of walls and roof
  2. Thermal conductivity of walls and roof
  3. Temperature difference between sides
• How does thermal conductivity relate to heat loss?

  Lower thermal conductivity equals lower heat loss
• What is a thermal insulator?

  A material with low thermal conductivity
• What determines the rate of energy transfer through a material?

  Thermal conductivity, temperature difference, thickness
• What is specific heat capacity?

  Energy needed to raise 1 kg by 1 °C
• How can you calculate the change in thermal energy?

  Using ∆E = m c ∆T
• What does infrared radiation belong to?

  Electromagnetic spectrum
• How does temperature affect infrared radiation emission?

  Higher temperature means more radiation emitted
• What happens when an object absorbs and emits infrared radiation equally?

  It remains at a constant temperature
• What occurs when an object absorbs more infrared radiation than it emits?

  Its temperature increases
• What is a black body in terms of radiation?

  A theoretical object absorbing all radiation
• How do greenhouse gases affect Earth's temperature?

  They absorb and re-emit infrared radiation
• Name three greenhouse gases.

  Water vapour, carbon dioxide, methane
• What human activities increase greenhouse gas levels?

  Deforestation, burning fossil fuels, livestock farming
• Why do greenhouse gases contribute to climate change?

  They trap heat by re-emitting radiation
• What must you measure to determine specific heat capacity?

  Mass, temperature rise, and time taken
• What are the key terms related to energy transfer by heating?

  • Absorb
  • Black body
  • Electromagnetic spectrum
  • Emit
  • Greenhouse gas
  • Infrared radiation
  • Specific heat capacity
  • Thermal conductivity
  • Thermal insulator