Conduction Through a Composite Wall
This Demonstration calculates temperature profiles and the heat flux for steady-state conduction through four walls in series; the total wall thickness is 10 cm. The temperature of the left wall can be changed with a slider; the temperature of the right wall is fixed at 45°C. The thicknesses of the first three walls are changed with sliders, and the composition of the end wall (fiberglass, brick, or lead) is selected with buttons. The heat flux is the same through each wall. 

Download the CDF file to view the simulation using the free Wolfram CDF player.