The apparatus consists of two small test cylinders of same size but different material. Each cylinder is fitted with a temperature sensor in the center to observe the temperature of cylinder when is under study. Any one of them is heated by a constant temperature water bath, till steady state is reached. During heating, temperature of the cylinder is a function of time and hence, heating of cylinder is under unsteady state heat transfer. A digital temperature indicator is provided. The hot water bath is provided with a heater and is controlled by digital temperature controller. A fixed speed agitator is also provided to maintain the constant bath temperature.