Sound waves

Wave

A disturbance that propagates or moves from the place it was created

Characteristics of Waves

Amplitude, period, frequency, and energy

Period

the time it takes for one complete up and down motion (T)

from one trough to trough or crest to crest

Trough

the lowest point of a wave; the minimum

Crest

the highest point of a wave; the maximum

Frequency

f= 1/T

unit: Hz

SI unit: cycle/seconds or 1/s or s^-1

^{the number of cycles in a second of the waveform}

Amplitude

Distance from the zero line to the trough or crest

Wavelength (λ)

the distance from trough to trough or crest to crest

wave velocity (v_w)

the speed at which the disturbance moves; aka propagation velocity or speed

v=distance/time

v=wavelength/period= λ/T

v=λ*f

Transverse wave

• waveform moving in a different direction than the individual waves

• the disturbance is perpendicular to the direction of propagation

  • Ex: the wave propagates in the horizontal direction while the surface is disturbed in the vertical direction

Longitudinal wave

Aka compressional wave

• the waveform and individual waves move in the same direction

• the distrubance is parallel to the direction of propagation

Superposition

Constructive interference

Destructive interference

Standing wave

Nodes

A

Antinodes

Fundamental frequency

Overtones

Beat frequency