Our common experience shows that the temperature of a material increases when it absorbs electromagnetic radiation. The passive solar heating of water and brewing of tea in a glass jar by sunlight are just two illustrations of this process. Is the food in a microwave oven heated by the same process? The answer is yes, to the extent that the food is heated by the absorption of electromagnetic radiation of microwave frequencies. At the same time we know that cold water kept in a thermally insulated opaque flask will not warm up by keeping it in the sun but will readily heat up in a microwave oven. So the exact mechanism of absorption of sunlight and microwaves by materials must be somewhat different. The present experiment is designed to demonstrate the fundamental aspects of microwave heating and in turn, to elucidate the dipolar dielectric loss phenomenon at the molecular level The emphasis is on the basic physics and the use of common inexpensive instrumentation and materials, rather than the accuracy of results. The students are also exposed to some of the issues dealing with the microwave processing of materials. Due to the familiarity with the experiment there is greater excitement for learning and, the students appear to remember the underlying principles more than from sophisticated experiments.