Mehrabian - Department of Mechanical Engineering, Shahid Bahonar University of Kerman,Iran

Most of engineering students do not have a clear idea of both the second law and entropy. What they learn from the standard texts for the second law is that the entropy AF448 of the universe increases during any spontaneous process. This, however is scientifically correct, but too complex and too jargon. We will see that the second law and entropy are simple and friendly concepts. The second law is based on human experience and is not derived from complicated theories and equations. This paper deals with simple processes that everyone might experience in his daily life and focuses on what is happening in every one of these processes in terms of energy conversion. As a result of this analysis, the fundamental science behind the second law will be revealed and a lucid picture of the entropy is presented. A summary of qualitative and philosophical aspects of entropy is given and the broad application of entropy to many different disciplines is illustrated.

Entropy, Second law, Energy dispersion, Localized energy, Universe, Temperature, Probability, Availability