Iron is a metallic compound. One property of metallic compounds are that they have many loose electrons.
Consider the two rods to be a singular rod, since they touch:
An uncountable number of electrons at one end of the rod are heated, so they gain kinetic energy. Those electrons then collide with other electrons, which energize those as well (although less), which is equal to adding heat. This is a pattern that will flow all the way through the rod.
Reason: They do this to gain stability. The reason they don’t actually transfer is because the difference in electronegativity values are above a certain value.
