Ch. 14 Waves and Energy Transfer

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Ch. 14 Waves and Energy Transfer

• Milbank High School

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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.

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Waves

• Waves are everywhere!
• Sound, light, radio, microwave, water, sine,
  cosine, telephone, earthquake, stadium, slinky
• Waverhythmic disturbance that carries energy
  through matter or space

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Mechanical Waves

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

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Waves Cont

• Wave Pulse
• Continuous Wave
• Transverse Wave
• Longitudinal Wave
• Compressions and rarefactions

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Surface Waves

• Combination of both(water)

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Wavelengths

• Crests
• Troughs
• Wavelength (?)
• Frequency f 1/T
• Hertz
• Speed of wave v ?f
• Ex Pg. 333

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Sec. 14.2Wave Behavior

• Objectives
• Relate a waves 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

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Wave Behavior

• Waves can be reflected
• Incident wave
• Reflected wave
• Sometimes passed on, sometimes reflected back,
  sometimes both

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Superposition of Waves

• Principle of superposition
• A wave meets a reflected wave
• Interference

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Destructive Interference

• Superposition of waves with equal but opposite
  amplitudes

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Constructive Interference

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

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Waves and Boundaries

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

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Waves in two dimensions

• Water waves
• Reflection
• Law of reflection
• Angle of incidence angle of reflection

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Refraction of waves in two dimensions

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

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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