SOUND
Vibrations, Waves, and Applications
What is Sound?
Sound is a form of energy produced by vibrating objects. These vibrations create disturbances that
travel through a medium (solid, liquid, or gas) as waves. Without vibrations, there is no sound, and
without a medium, sound cannot travel.
Sound waves are longitudinal waves, meaning the particles of the medium vibrate parallel to the
direction of wave propagation. This creates areas of compression (high density) and rarefaction
(low density) as the wave travels. Notably, sound cannot travel through a vacuum, as there are no
particles to vibrate.
Characteristics of Sound Waves
Wavelength (λ): Frequency (f):
The distance between two successive The number of vibrations or cycles per second.
compressions or rarefactions. Measured in Measured in Hertz (Hz). Higher frequency means
meters (m). higher pitch.
Amplitude (A): Speed (v):
The maximum displacement of a particle from its The distance sound travels per unit time.
resting position. Related to the loudness of the Depends on the medium's properties (e.g.,
sound. Measured in decibels (dB). temperature, density). v = fλ
The loudness of a sound depends on its amplitude - the larger the amplitude, the louder the sound.
The pitch of a sound depends on its frequency - the higher the frequency, the higher the pitch.
Quality or timbre allows us to distinguish between different sounds, even if they have the same pitch
and loudness.
Reflection of Sound
Sound waves, like light waves, can be reflected off surfaces. The laws of reflection apply: the angle
of incidence equals the angle of reflection, and the incident ray, reflected ray, and normal all lie in the
same plane.
Vibrations, Waves, and Applications
What is Sound?
Sound is a form of energy produced by vibrating objects. These vibrations create disturbances that
travel through a medium (solid, liquid, or gas) as waves. Without vibrations, there is no sound, and
without a medium, sound cannot travel.
Sound waves are longitudinal waves, meaning the particles of the medium vibrate parallel to the
direction of wave propagation. This creates areas of compression (high density) and rarefaction
(low density) as the wave travels. Notably, sound cannot travel through a vacuum, as there are no
particles to vibrate.
Characteristics of Sound Waves
Wavelength (λ): Frequency (f):
The distance between two successive The number of vibrations or cycles per second.
compressions or rarefactions. Measured in Measured in Hertz (Hz). Higher frequency means
meters (m). higher pitch.
Amplitude (A): Speed (v):
The maximum displacement of a particle from its The distance sound travels per unit time.
resting position. Related to the loudness of the Depends on the medium's properties (e.g.,
sound. Measured in decibels (dB). temperature, density). v = fλ
The loudness of a sound depends on its amplitude - the larger the amplitude, the louder the sound.
The pitch of a sound depends on its frequency - the higher the frequency, the higher the pitch.
Quality or timbre allows us to distinguish between different sounds, even if they have the same pitch
and loudness.
Reflection of Sound
Sound waves, like light waves, can be reflected off surfaces. The laws of reflection apply: the angle
of incidence equals the angle of reflection, and the incident ray, reflected ray, and normal all lie in the
same plane.
