Which statement best represents the mechanical definition of sound?

The mechanical definition of sound is accurately captured by the statement that it is transmitted through pressure waves in an elastic medium. Sound is fundamentally a mechanical wave, which means it relies on a medium, such as air, water, or solid materials, to propagate. When an object vibrates, it creates pressure variations in the surrounding medium, resulting in waves that travel outward.

Additionally, sound requires an elastic medium because the medium must be able to return to its original state after being disturbed; this is essential for the continued propagation of sound waves. In contrast, other options do not accurately describe the nature of sound. For instance, silence does not embody the vibrational activity associated with sound, and sound cannot travel through a vacuum as there are no particles to transmit the pressure waves. Similarly, sound is not visible energy; it exists as auditory sensations rather than a form of light or energy we can see. Thus, the definition highlighting the transmission of pressure waves in an elastic medium best encapsulates the mechanical aspect of how sound operates.