We know, heat transfer in a material happens due to vibration or vigorous to and fro movement of particles. Also, the density of wood is much more less than the density of iron i.e, distance between particles is more. Thus, particles in wood has more space to vibrate vigorously than the particles of iron. Why is iron better conductor of heat than wood? Does conduction of heat depend on density of a material? (OR) On what exactly does the conduction of heat depend on?