Waves

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Waves
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Wave Definition

• Traveling disturbance that carries energy from 1
  place to another (see handout)
• Wave source- an oscillation (repeated movement
  back forth) or vibration
• Medium- what a wave moves through (solids,
  liquids, and gases)

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Wave Classifications

• Mechanical Wave- must travel through a medium
  disturbs particles (sound waves).
• Electromagnetic Wave- does not need to travel
  through a medium can travel through a vacuum
  (light waves).

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Electromagnetic Waves(See handout)
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Wave Classifications

• Longitudinal
• Transverse

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Water Waves

• Water waves have transverse and longitudinal
  characteristics.
• Energy is transferred, but the particles stay
  essentially in the same place

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Parts of a Wave
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Reflection

• waves travel to the end of a medium and bounce
  back.
• 2 kinds
• Regular
• Diffuse

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Refraction

• waves bend after entering medium b/c they change
  velocity due to different mediums
• fast velocity firm medium
• slow velocity less firm medium

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Interference

• occurs when more than 1 wave passes through the
  same area
• 2 types- constructive and destructive

• constructive interference is when the wave combo
  has a greater disturbance than the individual
  waves (troughs and crests are lined up)
• destructive interference is when the combo of
  waves has less of a disturbance the individual
  waves (crests and troughs are not lined up)

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Diffraction

• Diffraction the bending of a wave around the
  edge of a barrier.

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Electromagentic Waves

• Electric fields perpendicular to Magnetic fields
• E- speed up or change direction to produce fields
• Make EM spectrum

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Radiowaves

• Transmit info from one antenna to another two
  ways.
• Amplitude Modulation
• Frequency Modulation
• Longest wavelength
• Uses Tvs radios cordless telephones RADAR

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Microwaves

• Sometimes referred to as high frequency radio
  waves.
• Uses http//science.hq.nasa.gov/kids/imagers/ems/
  micro.html

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Infrared Rays

• Classified as Far IR and Near IR
• Near infraredclose to visible light part of
  spectrum (size head of a pin)
• far infrared is close to the microwave part of
  spectrum. (microscopic)
• Uses http//science.hq.nasa.gov/kids/imagers/ems/
  infrared.html

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Ultraviolet Rays

• High frequency end of the spectrum.
• Can be beneficial (Vitamin D) yet harmful to
  humans.
• http//science.hq.nasa.gov/kids/imagers/ems/uv.htm
  l

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Visible Light

• Part of the spectrum the human eye can see.
• ROYGBIV combine to form white light
• http//science.hq.nasa.gov/kids/imagers/ems/visibl
  e.html

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X-Rays

• Discovered by German scientists named Roentgen
• Dense materials absorb them less dense do not.
• Can cause cell damage
• http//science.hq.nasa.gov/kids/imagers/ems/xrays.
  html

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Gamma Rays

• Highest frequency waves
• Most penetrating
• Released from radioactive materials
• http//science.hq.nasa.gov/kids/imagers/ems/gamma.
  html