Demonstrates very simply the difference in heat conductivity between four different metals – iron, copper, brass and aluminium. Each metal is embossed with either an ‘Fe’ (iron), ‘Cu’ (copper), ‘Br’ (brass) and an ‘Al’ (aluminium) respectively to identify them. The four 20 x 125mm metal strips are attached to a 113mm outside diameter aluminium ring. At the outer end of each metal strip is a round depression in which a piece of wax about the size of a pea is placed. When a point heat source, e.g. bunsen burner or spirit lamp, is placed where the metals meet in the centre of the ring heat is conducted along each metal strip. By observing the differing time it takes to melt the wax the heat conductivity of each metal can be compared.