In order for sound to travel, it requires a medium through which it can propagate. Sound is a mechanical wave, which means it needs a material medium to transmit its energy. This medium can be a solid, liquid, or gas, but it cannot travel through a vacuum (an empty space devoid of matter).
When a sound is produced, such as by vibrating objects or vocal cords, it creates pressure waves in the surrounding medium. These pressure waves cause particles in the medium to oscillate back and forth, transferring energy from one particle to the next. This transfer of energy allows the sound wave to propagate through the medium.
For example, in the case of air as the medium, sound travels by compressing and expanding air particles as the wave moves through it. Similarly, in a liquid or solid, the sound wave travels by causing vibrations in the molecules or atoms of the material.
It's important to note that sound travels at different speeds depending on the medium. For instance, sound generally travels faster in solids than in liquids, and faster in liquids than in gases.