ABSTRACT
Now, imagine a gas trapped in a long cylinder (tube) with a moveable piston at one end. And consider moving that piston briskly to the right and then reverse it back to its original position. As with the slinky, the movement to the right forces the molecules that the piston encounters into a tight band, and when reversed it produces a region in which the molecules are sparse-a condensation followed by a rarefaction. So it is exactly analogous to propagation in a slinky, as shown in Fig. 11.3.
