Sound Waves

Definition

Sound Waves are longitudinal pressure waves produced by a vibrating object that propagate through a compressible physical medium.

It is the primary communication channel for biological hearing and sonar.

Wave Properties:
Amplitude: Maximum displacement.
Wavelength ( $\lambda$ ): Distance between crests.
How to read: “lambda.”
Meaning: One full spatial cycle of the wave; inversely related to frequency at fixed speed.
Frequency ( $f$ ): Vibrations per second (Hertz).
How to read: “f.”
Meaning: Number of complete vibrations per second; measured in hertz (Hz).
Period ( $T$ ): Time for one vibration ( $T = 1/f$ ).
How to read: “T equals one over f.”
Meaning / when to use: Period and frequency are reciprocals; higher frequency means shorter period.
Wave Speed: $v = f\lambda$ .
How to read: “v equals f times lambda.”
Meaning: Fundamental wave equation linking speed, frequency, and wavelength.
Transverse Waves: Vibration is perpendicular to motion (e.g., light).
Longitudinal Waves: Vibration is parallel to motion (e.g., sound).
Sound Characteristics:
Pitch: Subjective impression of frequency.
Resonance: Large increase in amplitude when forced vibration matches natural frequency.
Beats: Interference pattern from slightly different frequencies.