A wave is a disturbance or vibration that transmits energy, but not matter.

Wave Terms

Medium = material that the waves travel through

     sound waves are vibrations of air

     ocean waves are ripples in water

Crest = high point on a wave

Trough = low point on a wave

Wavelength (λ) = distance traveled by a single wave

Amplitude (A) = maximum displacement from rest

See the Pen wave properties by lilgreenland (@lilgreenland) on CodePen.

The Wave Equation

v = velocity (m/s)

  • The velocity is determined by the medium.
  • λ = wavelength (m)

    f = frequency (Hz, 1/s) = cycles per seconds

    T = Period (s) = time for one cycle

    See the Pen waves by lilgreenland (@lilgreenland) on CodePen.

    Example: Playing middle C on a piano produces a sound with a frequency of 256 Hz. What is the period of the sound wave?

    T = 1/f
    T = 1/256 s

    Example: An air horn sounds at a frequency of 220 Hz. If the speed of sound in air is 330 m/s what is the wavelength of the sound wave?

    v = λf
    λ = v/f
    λ = 330/220
    λ = 1.5m

    Example: The distance between successive crests in a series of water waves is 4.0 m, and the crests travel 8.6 m in 5.0 s. Calculate the frequency of a block of wood bobbing up and down on these water waves.

    λ = 4.0m
    v = 8.6m/5.0s = 1.72m/s
    v = λ f
    f = v / λ
    f = 1.72 / 4.0
    f = 0.43 Hz