As the atoms depicted are no longer bonded to one another, information (motion) can no longer be transmitted as efficiently between atoms. Since the electrons in the atoms repel one another, P-wave motion can still be transmitted by interference between one atom and the next. Sound waves are one good example of a P-wave, as sound moves through the air quite efficiently.

S-waves on the other hand, cannot travel through fluids, since shear motion in one atom has no effect on the next atom in line.