Metals are good conductors of heat, as compared to wood, glass and plastic. In heat transfer, the thermal conductivity of a material is the property that determines its ability to conduct heat. However, a difference in thermal conductivities can be influenced by certain factors such as temperature, magnetic field, electrical conductivity and thermal anisotropy.
Metals have a high thermal conductivity and are therefore good conductors of heat. This is due to their structure. The atoms are close together and tightly packed. This is because the forces between the atoms are strong; therefore, energy is easily transferred between the atoms.
Wood and plastic have a low thermal conductivity, so they are poor conductors of heat because their atoms are far apart, and energy cannot easily be transferred between them.
Heat transfer across materials of high thermal conductivity occurs at a higher rate than across materials of low thermal conductivity. Materials with high thermal conductivity are used in heat sink applications, whereas, those with low thermal conductivity are used as insulators.
There are different modes of heat transfer. These include conduction, convection and radiation. Radiation is the simplest mode of heat transfer, because heat is not carried by moving atoms but by electromagnetic waves.