WavesWaves

Parts, Types, and Interactions

Definition of a WaveDefinition of a Wave

A disturbance that travels through a medium from one location to another location.

Waves transfer energy from one place to another.

Longitudinal WavesLongitudinal Waves

Medium travels parallel to direction of wave propagation. (sound, p-waves)

Transverse WavesTransverse Waves

Medium travels perpendicular to direction of wave propagation. (light, s-waves)

Types of WavesTypes of Waves

Water Waves (swell)Water Waves (swell)

Water waves are the superposition of longitudinal and transverse motions of water molecules.

Individual water molecules travel in circles.

Wave ParametersWave Parameters

Wavelength  ()        length or size of one oscillation

Amplitude (A)          strength of disturbance (intensity)

Frequency (f)    repetition

Wave ParametersWave Parameters

Wave PropertiesWave Properties

Waves are oscillations that transport energy. The energy of a wave is proportional to its

frequency. Fast oscillation = high frequency = high energy

Slow oscillation = low frequency = low energy The amplitude is a measure of the wave intensity.

SOUND: amplitude corresponds to loudness

LIGHT: amplitude corresponds to brightness

WavelengthWavelength Measure from any identical two successive points

5 10 15 20 25 30 35 40

WavelengthWavelength Measure from any identical two successive points

5 10 15 20 25 30 35 40

30 - 10 = 20

WavelengthWavelength Measure from any identical two successive points

There are 4 complete oscillations depicted here ONE WAVE = 1 COMPLETE OSCILLATION

5 10 15 20 25 30 35 40

22.5 - 2.5 = 20

FrequencyFrequency

Frequency = number of WAVES passing a stationary point per second (Hertz)

Remember…Remember…

Frequency (f) = number of oscillations passing by per second

Period (T) = length of time for one oscillation

T = 1/f f = 1/T

Wave SpeedWave Speed

Wave speed depends on wavelength and frequency:

v = f

Which animal can hear a shorter wavelength?

Cats (70,000 Hertz) or Bats (120,000 Hertz)

= v/f

Wave SpeedWave Speed

= v/f

Higher frequency = shorter wavelength

Lower frequency = longer wavelength

Wave InterferenceWave Interference

Waves add constructively.

Wave InterferenceWave Interference

Waves add constructively.

Wave InterferenceWave Interference

Waves cancel destructively.

Wave InterferenceWave Interference

Waves oscillate “out of phase”.½ wavelength phase shift

Wave InterferenceWave Interference

Waves at a BoundaryWaves at a Boundary

Reflection: waves “bounce” off barrier.

Waves at a BoundaryWaves at a Boundary

Reflection: Waves will always reflect in such a way that the angle at which they approach the barrier equals the angle at which they reflect off the barrier

Waves at a BoundaryWaves at a Boundary

Refraction of waves involves a change in the direction of waves as they pass from one medium to another

Waves at a BoundaryWaves at a Boundary

Diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path.

Waves at a BoundaryWaves at a Boundary

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