# Ch. 14 Waves and Energy Transfer Milbank High School.

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Ch. 14 Waves and Energy Transfer Milbank High School

Sec. 14.1 Wave Properties Objectives  Identify how waves transfer energy without transferring matter.  Contrast transverse and longitudinal waves.  Relate wave speed, wave-length, and frequency.

Waves Waves are everywhere!  Sound, light, radio, microwave, water, sine, cosine, telephone, earthquake, stadium, slinky… Wave—rhythmic disturbance that carries energy through matter or space

Mechanical Waves Require a medium  Water, air, ropes Will not occur in a vacuum Non-mechanical waves  Electromagnetic  light

Waves Con’t Wave Pulse Continuous Wave Transverse Wave Longitudinal Wave  Compressions and rarefactions

Surface Waves Combination of both…(water)

Wavelengths Crests Troughs Wavelength (λ) Frequency f = 1/T  Hertz Speed of wave v = λf Ex: Pg. 333

Sec. 14.2 Wave Behavior Objectives  Relate a wave’s speed to the medium in which the wave travels  Describe how waves are reflected and refracted at boundaries between media, and explain how waves diffract  Apply the principles of superposition to the phenomenon of interference

Wave Behavior Waves can be reflected Incident wave Reflected wave  Sometimes passed on, sometimes reflected back, sometimes both

Superposition of Waves Principle of superposition  A wave meets a reflected wave Interference

Destructive Interference Superposition of waves with equal but opposite amplitudes

Constructive Interference Amplitudes are in the same direction Creates a larger wave Antinode Node

Waves and Boundaries Boundaries change speed and wavelength Frequency stays the same Type of barrier determines amount of change

Waves in two dimensions Water waves Reflection  Law of reflection  Angle of incidence = angle of reflection

Refraction of waves in two dimensions Change in direction of waves at the boundary between two different media

Diffraction Spreading of waves around a barrier Water waves around a coral reef Or more than one object  Interference would occur Long wavelengths diffract the least  AM vs FM radio

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