As an expert in the field of acoustics, I can explain that sound waves are typically longitudinal waves when they travel through gases, plasmas, and liquids. These are also known as compression waves because they cause the particles in the medium to move back and forth in the same direction as the wave is traveling. Sound waves require a medium to propagate, and in these mediums, the particles cannot move sideways, only longitudinally. However, in solids, sound waves can be transmitted as both longitudinal waves and transverse waves. In solids, the particles are closely packed and can move in different directions, allowing for the possibility of transverse wave propagation as well. In summary, sound waves are longitudinal in gases, plasmas, and liquids, and can be either longitudinal or transverse in solids. read more >>

Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves. It requires a medium to propagate. Through solids, however, it can be transmitted as both longitudinal waves and transverse waves.read more >>