THERMAL CONDUCTIVITY BARS

Ideal for comparison of thermal conductivity of different metals quickly and conveniently. Unique, new conductivity bar set features convenient liquid crystal indicators mounted in robust holders. Comprises four identical metal bars of same shape and size, each of different metal – copper, aluminium, brass and steel, held firmly parallel to one another in a rigid moulded carrier with a hole for convenient suspension. Conductivity value of each bar is clearly marked on the back of the support. The sensitive liquid crystal temperature indicators working in low temperature range, are attached to the front of all the four metal bars. The temperatura indicators are marked at 1 cm interval to facilitate charting the movement of temperature gradients. The rate of heat flow is indicated by timing the colour change across these markers. The demonstration requires only a beaker or container of hot water, thus doing away with open flames, hotplates, or messy “melting wax” method of comparison. Within seconds of placing the ends of the bars in hot water, a visible “heat pulse” travels to the copper bar; the steel bar takes several minutes to conduct the heat to its upper end. Timing the “heat pulses” enables estimation of the relative conductivities and their comparison with the stated the,oretical values. Also demonstrates the conduction of heat from a heated bar to its end, if cooled.