energy transfer by heating

• The thermal conductivity of a material tells you how quickly energy is transmitted through it by thermal conduction.
• Heating bills can be expensive so it is important to reduce the rate of heat loss from buildings.
• Some factors that affect the rate of heat loss from a building include:

  1. the thickness of its walls and roof

  2. the thermal conductivity of its walls and roof.
• lower thermal conductivity = lower rate of heat loss
• The thermal conductivity of the walls and roof can be reduced by using thermal insulators.
• A thermal insulator is a material which has a low thermal conductivity
• The rate of energy transfer through an insulator is low.
• The energy transfer per second through a material depends on:

  1 the material’s thermal conductivity

  2 the temperature difference between the two sides of the material

  3 the thickness of the material.
• When a substance is heated or cooled the temperature change depends on:

  • the substance’s mass

  • the type of material

  • how much energy is transferred to it.
• Every type of material has a specific heat capacity
• specific heat capacity – the amount of energy needed to raise the temperature of 1 kg of the substance by 1 °C.