How is sound defined?

The definition of sound is fundamentally tied to its nature as a mechanical wave that travels through various media, primarily through particles in air, liquids, and solids. Sound is created when an object vibrates, causing disturbances in nearby particles. These vibrations create compressions and rarefactions that propagate through the medium, which we perceive as sound.

The choice surrounding noise carried through particles in the air accurately reflects this definition. Sound waves rely on particles—such as air molecules—to transfer energy from one location to another. In this case, air acts as the medium through which sound travels, making the option a clear representation of how sound operates in our environment.

Understanding why the other choices do not align with the definition of sound is vital for grasping the full concept. Vibration occurs in liquids and solids as well as air; however, defining sound solely as a vibration in liquids excludes air and solids, limiting the context of sound propagation. The statement regarding light energy converted to sound misrepresents the fundamental nature of sound, as light and sound are two distinct forms of energy with different mechanisms. Lastly, sound cannot travel in a vacuum, as there are no particles to carry the vibrations, making the reference to sound as a vibration in a vacuum inaccurate.