ABSTRACT
The pressure inside the balloon is much higher, though, and the molecules are compressed much more tightly together . . . like people packed into a crowded subway car (Figure 2.1a). When the balloon is popped . . . ‘‘POW!’’ (Figure 2.1b), the tightly compressed molecules under high pressure begin to exert an outward force upon their neighbors in an effort to move toward areas of lower pressure. When the neighboring set of molecules has been compressed, they will continue to exert an outward force upon the next set of lower-pressured neighbors (Figure 2.1c) . . . in an ongoing outward motion that continues until the molecules have used up their energy in the form of heat.
