Sound waves are mechanical waves that propagate through a medium. In general, compressions and rarefactions in sound waves travel through matter, such as gases (like air), liquids, or solids.
In the case of gases, like air, sound waves travel through the successive compression and rarefaction of air molecules. When a sound wave propagates, it causes regions of higher pressure called compressions, where air molecules are closer together, and regions of lower pressure called rarefactions, where air molecules are more spread out.
In liquids, such as water, sound waves also propagate through the compression and rarefaction of molecules. The molecules in liquids are closer together compared to gases, so sound waves travel at a higher speed in liquids than in gases.
In solids, sound waves travel through the compression and rarefaction of molecules or atoms that are closely packed together. The particles in solids are tightly bonded, allowing sound waves to propagate rapidly.
In summary, compressions and rarefactions in sound waves normally travel through matter, including gases, liquids, and solids. The specific characteristics of the medium, such as the density and elasticity, influence the speed at which sound waves propagate.