Thermal Conduction (Cambridge International IGCSE Science)

Thermal conduction in solids

Spec point — P2.3.2

Extended Tier Only

• Conduction is the transfer of heat from one region to another through particle vibrations and the movement of free electrons

• Conduction is the main method of thermal energy transfer in solids

• Metals are the best thermal conductors

  • This is because they have a high number of free electrons

Conduction: the atoms in a solid vibrate and collide, transferring energy

• Conduction can occur through two mechanisms:

  • Atomic vibrations
  • Free electron collisions

• When a substance is heated, the atoms, or ions, start to move around (vibrate) more

  • The atoms at the hotter end of the solid will vibrate more than the atoms at the cooler end
  • As they do so they bump into each other, transferring energy from atom to atom
  • These collisions transfer internal energy until thermal equilibrium is achieved throughout the substance
  • This occurs in all solids, metals and non-metals alike

• Additionally, if a solid contains free electrons, these can travel through the material freely and transfer thermal energy through collisions