Thermal conductivity of four different metals (NCPQ)

A heat source (Bunsen burner) is placed under a cast iron ring to which four different metals have been rivetted. The thermal energy is conducted along each rod at different speeds and eventually melts the bead of wax at the end. You can see the wax melt in order of thermal conductivity (from highest to lowest). The slowest is for the stainless steel and it actually doesn't melt as the heat is lost by convection and radiation in a way that causes it to reach an equilibrium temperature lower than the melting point of the way. A hotter heat source would overcome this.

Reference: New Century Physics for Queensland U 1 & 2, 3rd Ed, December 2018. Oxford University Press. See Chapter 3.2 page 113.

Filmed at Moreton Bay College, Brisbane, by Dr Richard Walding, author of New Century Physics for Queensland, 3rd ed, 2019. Oxford University Press.
Website: seniorphysics.com/ncpq