The Properties of Waves and Sound

Vocabulary flashcards covering key concepts from interference, standing waves, Doppler effect, and musical sound.

Interference

The combined effect of two or more overlapping waves, which can affect the resulting amplitude or intensity.

Constructive interference

When crests (or troughs) of two waves align, producing a wave with increased amplitude.

Destructive interference

When a crest overlaps a trough, resulting in reduced amplitude.

Superposition

The combination of two or more waves; in phase, it can produce a wave with increased amplitude (and intensity for longitudinal waves).

Transverse wave

A wave in which the displacement is perpendicular to the direction of travel.

Longitudinal wave

A wave in which the displacement is parallel to the direction of travel.

Standing wave

A wave pattern formed by the interference of incident and reflected waves, featuring nodes and antinodes.

Node

A point in a standing wave with zero amplitude.

Antinode

A point in a standing wave with maximum amplitude.

Beats

Periodic variations in loudness due to interference, occurring when two frequencies are close together.

Doppler effect

A change in the observed frequency due to the motion of the source or observer.

Frequency

The number of vibrations per second; determines the pitch of a sound.

Pitch

Perceived frequency of a sound; higher frequency means higher pitch.

Wavelength

The distance between successive crests (or troughs) of a wave.

Speed of sound

The rate at which sound waves propagate through a medium.

Intensity

The perceived loudness or energy of a sound, related to amplitude.

Quality (timbre)

The characteristic that distinguishes sounds with the same pitch and loudness, influenced by harmonics and partials.

Harmonics

Frequencies that are integer multiples of the fundamental frequency, contributing to timbre.

Fundamental frequency

The lowest frequency of vibration, which determines the pitch.

Noise vs. Music

Noise has no clear repeatable pattern; music has a repeatable frequency, wavelength, and speed.

Phase

The relative position of two waves' cycles, indicating whether they are in sync.

In-phase

Waves whose corresponding points reach the same phase at the same time (constructive alignment).

Out-of-phase

Waves whose corresponding points are not aligned in time, often leading to interference.

Noise cancellation

Application of destructive interference by producing an opposite-phase signal to cancel unwanted noise.