Notes on Source, Medium, Receptor, and Transmission

Source: a sound-producing event, e.g., me talking describes the origin of sound.
Medium: the air through which the sound travels.
Receptor: the ears that receive the sound.
Transmission: the energy is carried as vibrations through the air from source to receptor.
Brain processing: the brain translates these energy signals into what we understand as sound.
Visual cue described: a graphic illustrating that sound is composed of frequencies and cycles.
The concept that sound consists of cycles and frequencies, with cycles measured over time, is foundational knowledge (fresh from high school).