ABSTRACT
Before starting our discussions on polymers, let us do some simple experiments with rubber bands. Get one of those wide rubber bands — those used by the post office to tie mail should work fine. Stretch the rubber band about two to three times its natural length and hold it there. Get a rough idea of its temperature by touching the rubber band with your lower lip. You may notice that it gets slightly warm. Surprised? Now, relax the rubber band quickly to its natural length and get a feel of the temperature by your lower lip again. It gets quite cool (Figure 7.1). Really surprised?
