A simple, effective apparatus demonstrates the heat conductivity of various metals. Four metals bars (Copper, Aluminum, Brass and Steel) are mounted on a base with a hole for suspension. Every metal bar has same cross-sectional area and its conductivity value is marked on the back of the base. The sensitive temperature indicators are attached to the front of each of the four metal bars. The color of the temperature indicator changes with the change in temperature. Place the bars in a beaker of hot water and compare their relative conductivities. With instructions.