As a seismologist with expertise in the study of seismic waves, I can explain the behavior of different types of waves in various media. P waves, also known as primary or compressional waves, are a type of longitudinal wave that can indeed travel through solids, liquids, and gases. This is because P waves involve the particles of the medium moving back and forth in the same direction as the wave's motion. Since gases have particles that can move in these manners, P waves can propagate through them. On the other hand, S waves, or secondary or shear waves, are transverse waves where the particle motion is perpendicular to the direction of wave propagation. Shear waves require a medium that can withstand shear stress, which is something that only solids can provide. Therefore, S waves cannot travel through liquids or gases, as these states of matter lack the rigidity necessary to support shear stress. In summary, P waves can travel through gases, but S waves cannot. read more >>

This explains why sound waves (which are a type of compressional wave) can travel through solids, liquids and gases. P waves are compressional waves. Therefore, they too can travel through solids, liquids and gases. Shear waves can travel only through solids.read more >>