Waves Parts, Types, and Interactions
Definition 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 Waves Medium travels parallel to direction of wave propagation. (sound, p-waves)
Transverse Waves Medium travels perpendicular to direction of wave propagation. (light, s-waves)
Types of Waves
Water Waves (swell) Water waves are the superposition of longitudinal and transverse motions of water molecules. Individual water molecules travel in circles.
Wave Parameters Wavelength ( ) length or size of one oscillation Amplitude (A) strength of disturbance (intensity) Frequency (f) repetition
Wave Parameters
Wave 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
Wavelength Measure from any identical two successive points
Wavelength Measure from any identical two successive points = 20
Wavelength Measure from any identical two successive points There are 4 complete oscillations depicted here ONE WAVE = 1 COMPLETE OSCILLATION = 20
Frequency Frequency = number of WAVES passing a stationary point per second (Hertz)
Remember… Frequency (f) = number of oscillations passing by per second Period (T) = length of time for one oscillation T = 1/ff = 1/T
Wave 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 Speed = v/f Higher frequency = shorter wavelength Lower frequency = longer wavelength
Wave Interference Waves add constructively.
Wave Interference Waves add constructively.
Wave Interference Waves cancel destructively.
Wave Interference Waves oscillate “out of phase”. ½ wavelength phase shift
Wave Interference
Waves at a Boundary Reflection: waves “bounce” off barrier.
Waves 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 Boundary Refraction of waves involves a change in the direction of waves as they pass from one medium to another
Waves 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 Boundary animations