Question

People are able to hear footsteps because the sound made by a foot hitting the floor travels through the air to reach their ears.

Answer 1

Your sentence is basically right — airborne sound is the obvious route — but it misses an important second path. When a foot strikes a floor it produces both:

- Airborne sound: the impact launches pressure waves into the air that travel to a listener’s ears. Those waves contain higher-frequency components that are easier to hear across a room; sound level falls with distance and is shaped by room reflections and absorption.

- Structure-borne sound: the impact also excites elastic waves in the floor/structure. Those vibrations can travel through the building and either radiate back into the air at some other location (making the floor or ceiling act like a loudspeaker) or reach a listener directly via contact/bone conduction. Low-frequency energy transmits especially well through structure.

Which path dominates depends on materials, coupling and frequency: hard floors and light construction favor structure-borne transmission; carpets and soft underlay reduce airborne radiation and impact noise. Practical consequences: insulating/decoupling floors, adding rugs or underlay, and soft-soled footwear all reduce how loud footsteps are to others.