Sound
Sound is mechanical vibration that travels through a material medium as waves. Audible sound is the portion of these vibrations detected by hearing.
Acoustic wave: A mechanical wave in a medium, commonly involving oscillations of pressure or particle displacement. Sound propagates through a medium as acoustic waves.
Amplitude: The maximum displacement or value of an oscillation relative to its equilibrium. Wave amplitude relates to sound pressure and often to perceived loudness.
Acoustics: The science of sound, including its production, transmission, and effects. Acoustics studies the physical behavior underlying sound.
Electromagnetic wave: A disturbance of electric and magnetic fields that propagates through space and does not require a material medium. Unlike sound, electromagnetic waves can travel through a vacuum.
Echo: A reflected sound heard after the original sound, with enough delay to be perceived separately. An echo is a distinct return of sound after reflection.
Frequency: The number of cycles of a repeating event per unit time, measured in hertz. For periodic sound, frequency helps determine perceived pitch.
Sound intensity: The acoustic power transmitted per unit area, usually measured in watts per square metre. Intensity quantifies energy flow in a sound wave.
Musical acoustics: The study of how musical sounds are produced, transmitted, and perceived. Instruments shape sound waves into tones and musical timbres.
Light: Electromagnetic radiation detectable by the human visual system. Light is often compared with sound, but it is not a mechanical wave.
Reverberation: The persistence of sound in an enclosed space as reflections continue after the source stops. Repeated reflections make sound linger in rooms and halls.